Porous polymer materials for li+ adsorbents and battery cathodes

Abstract

Herein disclosed is a covalent organic framework comprising: polymer chains configured to form a covalently crosslinked polymer network, wherein each of the polymer chains comprises monomeric units each comprising a pyrrole-based moiety, wherein the pyrrole-based moiety is absent of any metal and comprises: a porphyrin moiety having an optionally substituted meso carbon, or a pyrrole moiety having an optionally substituted methylene group, or a mixture thereof; and a linker comprising two halogens, wherein the linker, if present, renders a non-covalent halogen bond which couples one nitrogen bond of one pyrrole-based moiety and one halogen of the linker and another non-covalent halogen bond which couples one nitrogen of another pyrrole-based moiety and the other halogen of the linker, and the linker, when removed or if absent, renders a void which defines a pore in the covalently crosslinked polymer network. A method for forming the covalent organic framework is also disclosed.

Description

POROUS POLYMER MATERIALS FOR LI+ADSORBENTS AND BATTERY CATHODESCross-Reference to Related Application

[0001] This application claims the benefit of priority of Singapore Patent Application No. 10202500339R, filed 6 February 2025, the content of it being hereby incorporated by reference in its entirety for all purposes.Technical Field

[0002] The present disclosure relates to a covalent organic framework, and a method for forming the covalent organic framework.Background

[0003] Seawater reverse osmosis (SWRO) may be one of Singapore’s key strategic thrusts, as desalinated water may be expected to meet up to 30% of Singapore’s future water needs by 2060. With growing demand for desalinated water in Singapore and other countries, a massive amount of SWRO brine (concentrates rejected from the process) may be produced in the world and its amount appears to be rapidly increasing. Ions present in SWRO brine, such as Li+ions, may be valuable metal ions. The recovery of such high-value resources may bring economic benefit and hence sustainable desalination.

[0004] Therefore, there is a need for an effective method for recovery of precious metals from SWRO brine. Li recovery potentially amounts to an economic benefit of >300 million SGD per year in Singapore. Li is highly demanded in batteries, for instance. Li is currently mined on land (from salt lakes and rocks) in particular countries, and those countries govern Li trading. Harnessing Li from seawater may be borderless and may offer great market potential.

[0005] Lithium ion batteries may be widely used. Batteries may consist of inorganic cathodes made of critical metals such as cobalt, nickel and manganese. Thus, batteries rely heavily on these critical metals. Their sources may be controlled by a limited number of countries and companies globally, potentially leading to unexpected price fluctuations and supply chain disruptions due to geopolitical tensions. Thedevelopment of critical materials -free cathodes may be a solution to overcome this problem in batteries.

[0006] There is thus a need to provide for a solution that addresses one or more of the limitations mentioned above.Summary

[0007] In a first aspect, there is provided for a covalent organic framework comprising: polymer chains configured to form a covalently crosslinked polymer network, wherein each of the polymer chains comprises monomeric units each comprising a pyrrole-based moiety,wherein the pyrrole-based moiety is absent of any metal and comprises:a porphyrin moiety having an optionally substituted meso carbon, ora pyrrole moiety having an optionally substituted methylene group, ora mixture thereof;anda linker comprising two halogens, wherein the linker, if present, renders a non-covalent halogen bond which couples one nitrogen bond of one pyrrole-based moiety and one halogen of the linker and another non-covalent halogen bond which couples one nitrogen of another pyrrole-based moiety and the other halogen of the linker, and the linker, when removed or if absent, renders a void which defines a pore in the covalently crosslinked polymer network.

[0008] In another aspect, there is provided for a method for forming the covalent organic framework of various embodiments of the first aspect, the method comprising:providing a mixture comprising:a monomer or an oligomer, wherein the monomer or the oligomer comprises a pyrrole-based moiety, wherein the pyrrole-based moiety is absent of any metal and comprises:a porphyrin moiety having an optionally substituted meso carbon,ora pyrrole moiety having an optionally substituted methylene group;a linker comprising two halogens; anda photo-initiator;co-crystallizing the monomer or the oligomer, with the linker, to form a cocrystal comprising the linker coupled to the monomer or the oligomer via halogen bond; andsubjecting the co-crystal to solid phase polymerization to form a covalently crosslinked polymer network.Brief Description of the Drawings

[0009] The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the present disclosure. In the following description, various embodiments of the present disclosure are described with reference to the following drawings, in which:

[0010] FIG. 1A shows the synthesis of multi-vinyl methylene pyrrole oligomer (MPO). The MPO may be referred to as a “MPO monomer” in the present disclosures, as the MPO may be deemed a basic unit for forming the covalent organic frameworks. FIG. 1A also shows porphyrin (multi-vinyl calix[4]pyrrole, also denoted as CP monomer) synthesized.

[0011] FIG. 1B shows various “MPO monomers” of the present disclosure.

[0012] FIG. 1C shows various CP monomers of the present disclosure. P(PPR-MAH), P(PPR-C3A) and P(PPR-CPK) are some of the polymers showing better uniformity in the nanoporous structures. P(PPR-CsK). P(PPR-C8K), P(PPR-C4K), and P(PPR-CPK) arc some of the polymers showing better performance of metal ion adsorption and selectivity.

[0013] FIG. 1D shows synthesis of MPO-based covalent organic frameworks (COFs) via halogen-bonding-based free radical solid phase polymerization (XB-based SPP).

[0014] FIG. IE show synthesis of the porphyrin-containing monomers (CP monomers).

[0015] FTG. 2 is a table showing polymerizations of MPO-containing monomers in solid phase (SPP) with XB linker, solid phase (SPP) without XB linker, and solution (liquid) phase without XB linker under UV light ( = 365 nm) at room temperature. “SPP with XB denotes polymerization of three component cocrystal of monomer, I-C6F4-I (XB linker), and DMPA (photo initiator), SPP without XB denotes polymerization of two component cocrystal of monomer and DMPA, and Solution denotes polymerization of three component solution of monomer, dichloromethane (solvent), and DMPA.bPolystyrene-calibrated DMF-GPC peak-top molecular weight (Mp) of the soluble polymer. Because of the presence of oligomers and possible clusters of LiBr contained in the DMF eluent, the GPC baseline was not horizontal for all cases. Thus, the number-average molecular weight and dispersity could not be determined accurately, and hence the Mpvalue was determined instead.

[0016] FIG. 3 shows illustrations of possible network structures in COFs from MPO monomers.

[0017] FIG. 4 shows illustration of possible pores in COFs formed from MPO monomers.

[0018] FIG. 5A shows TEM images of exfoliated MPO-C5K.

[0019] FIG. 5B shows TEM images of exfoliated MPO-CeK.

[0020] FIG. 5C shows TEM images of exfoliated MPO-CPK.

[0021] FIG. 5D shows TEM images of exfoliated MPO-CsK.

[0022] FIG. 5E show s TEM images of exfoliated MPO-C4K.

[0023] FIG. 6A is an AFM image of exfoliated MPO-C5K.

[0024] FIG. 6B is an AFM image of exfoliated MPO-CPK.

[0025] FIG. 7 is a table showing metal ion adsorption and desorption using model brine water (containing Li+, Na+, and Mg2+) with Li mass ratio of 340 mg of Li ion per 1 g of adsorbent.aBecause of the very high concentrations of Na+and Mg2+in the brine, the decrease in the Na+and Mg2+concentrations in the brine via the adsorption was negligibly small and unable to be detected using ICP-OES. Thus, the adsorption of Na+and Mg2+was indirectly detected from the desorbed amounts of Na+and Mg2+in the subsequent desorption process, because Na+and Mg2+were fully eluted out after the desorption process.

[0026] FIG. 8 is a table showing metal ion adsorption and desorption in mixture of ions Li++Na++Mg2+system in model brine (with Li mass ratio of 340 mg of Li ion / 1 g of P(MPO-CsK) adsorbent) in ten cycles.[a]Because of the very high concentrations of Na+and Mg2+in the brine, the decrease in the Na+and Mg2+concentrations in the brine via the adsorption was negligibly small and unable to be detected using ICP-OES. Thus, the adsorption of Na+and Mg2+was indirectly detected from the desorbed amounts of Na+and Mg2+in the subsequent desorption process, because Na+and Mg2+were fully eluted out after the desorption process.

[0027] FIG. 9 shows a table comparison of Li+ion adsorption capacity among P(MPO-CsK) adsorbent and traditional adsorbents with high adsorption records.aBecause of the very high concentrations of Na+and Mg2+in the brine, the decrease in the Na+and Mg2+concentrations in the brine via the adsorption was negligibly small and unable to be detected using ICP-OES. Thus, the adsorption of Na+and Mg2+was indirectly detected from the desorbed amounts of Na+and Mg2+in the subsequent desorption process, because Na+and Mg2+were fully eluted out after the desorption process. " HMO was delithiumed from lithium manganese oxide (LMO) that was purchased from Sigma Aldrich. HTO was delithiumed from lithium titanate (LTO) that was purchased from Sigma Aldrich. PPDA was obtained.

[0028] FIG. 10A is an XPS spectra image for three cycles of adsorption-desorption of P(MPO-C5K).

[0029] FIG. 10B is a set of SEM-EDX images for three cycles of adsorption-desorption of P(MPO-CsK).

[0030] FIG. 11 is a table showing metal ion adsorption and desorption using model brine water (containing Li+, Na+, and Mg2+) with Li mass ratio of 340 mg of Li ion per 1 g of P(MPO-CsK) in four cycles (without desorption and neutralization after each circle). “ Because of the very high concentrations of Na+and Mg2+in the brine, the decrease in the Na+and Mg2+concentrations in the brine via the adsorption was negligibly small and unable to be detected using ICP-OES. Thus, the adsorption of Na+and Mg2+was indirectly detected from the desorbed amounts of Na+and Mg2+in the subsequent desorption process, because Na+and Mg2+were fully eluted out after the desorption process.

[0031] FIG. 12 is a table showing metal ion adsorption and desorption using brine water (containing Li+, Na+, and Mg2+) with Li mass ratio of 340 mg of Li ion per 1 g of MPO-C5K monomer adsorbent. “ Because of the very high concentrations of Na+and Mg2+in the brine, the decrease in the Na+and Mg2+concentrations in the brine via the adsorption was negligibly small and unable to be detected using ICP-OES. Thus, the adsorption of Na+and Mg2+was indirectly detected from the desorbed amounts of Na+and Mg2+in the subsequent desorption process, because Na+and Mg2+were fully eluted out after the desorption process.

[0032] FIG. 13 shows general chemical structure of the MPO monomers that can be used in such polymerization of the present disclosure, “n” denotes a positive integer and can be at least 1.

[0033] FIG. 14A shows the synthesis of the COF from porphyrin-containing monomers (CP monomers) via XB-SPP.

[0034] FIG. 14B shows a hierarchical porous polymer structure based on a poly(porphyrin) network. The structure defines a nanopore (secondary void) having an effective diameter in the range of about 5 nm to 30 nm, as indicated at the center of the figure. The poly(porphyrin) framework can be configured in a radially symmetric, star-like architecture, in which porphyrin units are interconnected to form a rigid, crosslinked network. This network encloses and stabilizes the nanopore, which is spatially distinct from smaller primary pores present within the polymer framework.

[0035] FIG. 15 is a table showing polymerization of porphyrin-containing monomers in solid phase (SPP) with XB linker, in solid phase (SPP) without XB linker, and in solution (liquid) phase without XB linker under UV light (λ = 365 nm) at room temperature.aPolystyrene-calibrated DMF-GPC peak-top molecular weight (Mp) of the soluble polymer. Because of the presence of oligomers and possible clusters of LiBr contained in the DMF eluent, the GPC baseline was not horizontal for all cases. Thus, the number- average molecular weight and dispersity could not be determined accurately, and hence the Mpvalue was determined instead.

[0036] FIG. 16A illustrates a possible one-dimensional structure of CP-based COFs.

[0037] FIG. 16B illustrates a possible two-dimensional structure of CP-based COFs.

[0038] FIG. 16C illustrates a possible three-dimensional structure of CP-based COFs.

[0039] FIG. 17 illustrates possible pores in a porphyrin-based COF.

[0040] FIG. 18A shows an AFM image of exfoliated PPR-C5K.

[0041] FIG. 18B shows an AFM image of exfoliated PPR-CPK.

[0042] FIG. 19A shows TEM images of exfoliated PPR-C6K.

[0043] FIG. 19B shows TEM images of exfoliated PPR-CsK.

[0044] FIG. 19C shows TEM images of exfoliated PPR-CPK.

[0045] FIG. 19D shows TEM images of exfoliated PPR-CsK.

[0046] FIG. 19E shows TEM images of exfoliated PPR-MPC.

[0047] FIG. 19F shows TEM images of exfoliated PPR-C4K.

[0048] FIG. 20 is a table showing metal ion adsorption and desorption in mixture of ions Li++Na++Mg2+system in model brine (with Li mass ratio of 340 mg of Li ion / 1 g of adsorbent).aChanges of Na+and Mg2+concentrations in the adsorption solution were out of detection limit of ICP-OES, hence it was unable to detect the adsorption of Na+and Mg2+directly. The Na+and Mg2+adsorption was measured in the desorption solution, assuming that Na+and Mg2+were totally eluted out after desorption.

[0049] FIG. 21 is a table comparing Li+ion adsorption capacity between P(PPR-CsK) adsorbent and the traditional highest records. ° Changes of Na+and Mg2+concentrations in the adsorption solution were out of detection limit of ICP-OES, hence it was unable to detect the adsorption of Na+and Mg2+directly. The Na+and Mg2+adsorption was measured in the desorption solution, assuming that Na+and Mg2+were totally eluted out after desorption.

[0050] FIG. 22 shows the XPS spectra and SEM-EDS images for three cycles of adsorption-desorption of P(PPR-C5K).

[0051] FIG. 23 is a table showing metal ion adsorption and desorption in mixture of ions Li++Na++Mg2+system in model brine (with Li mass ratio of 340 mg of Li ion / 1 g of P(PPR-CsK) adsorbent) in four cycles (without desorption and activation after each circle).

[0052] FIG. 24 is a table showing metal ion adsorption and desorption in mixture of ions Li++Na++Mg2+system in model brine with treatments (with Li mass ratio of 340 mg of Li ion / 1 g of porphyrin-CsK monomer adsorbent.

[0053] FIG. 25 shows the chemical structure of a porphyrin-based (CP) monomer that can be used in polymerization of the present disclosure.

[0054] FIG. 26 shows anchoring of the porous COFs adsorbent on fibers.

[0055] FIG. 27 shows a setup for forming a membrane made using COFs of the present disclosure.

[0056] FIG. 28 is a table showing the metal ion adsorption and desorption in mixture of ions Li++Na++Mg2+system in real SWRO brine (with Li mass ratio of 340 mg of Li ion / 1 g of P(MPO-C5K(Et) adsorbent) in two cycles using a mixture of 1M HCl and methanol (MeOH) (HCl / MeOH 7 / 3 %v / %v) as the eluent.aBecause of the very high concentrations of Na+and Mg2+in the brine, the decrease in the Na+and Mg2+concentrations in the brine via the adsorption was negligibly small and unable to be detected using ICP-OES. Thus, the adsorption of Na+and Mg2+was indirectly detected from the desorbed amounts of Na+and Mg2+in the subsequent desorption process, because Na+and Mg2+were fully eluted out after the desorption process.

[0057] FIG. 29 is a table showing the metal ion adsorption and desorption in mixture of ions Li++Na++Mg2+system in real SWRO brine (with Li mass ratio of 340 mg of Li ion / 1 g of P(MPO-C5K(CHO) adsorbent) in two cycles using a mixture of 1M HCl and methanol (MeOH) (HCl / MeOH 7 / 3 %v / %v) as the eluent.aBecause of the very high concentrations of Na+and Mg2+in the brine, the decrease in the Na+and Mg2+concentrations in the brine via the adsorption was negligibly small and unable to be detected using ICP-OES. Thus, the adsorption of Na+and Mg2+was indirectly detected from the desorbed amounts of Na+and Mg2+in the subsequent desorption process, because Na+and Mg2+were fully eluted out after the desorption process.Detailed Description

[0058] The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the present disclosure may be practised.

[0059] Features that are described in the context of an embodiment may correspondingly be applicable to the same or similar features in the other embodiments. Features that are described in the context of an embodiment may correspondingly be applicable to the other embodiments, even if not explicitly described in these other embodiments. Furthermore, additions and / or combinations and / or alternatives as described for a feature in the context of an embodiment maycorrespondingly be applicable to the same or similar feature in the other embodiments.

[0060] The present disclosure relates to a covalent organic framework (COF). The covalent organic framework, advantageously, may be porous polymer material usable as adsorbents of lithium (Li+) ions with considerably high adsorption capacity and considerably excellent adsorption selectivity and may potentially serve as organic cathodes of batteries, such as lithium-ion batteries.

[0061] Covalent organic frameworks of the present disclosure can be derived from and / or include vinyl methylene pyrrole oligomer (e.g., multi-vinyl methylene pyrrole oligomer-containing porous polymer materials), which may be abbreviated MPO-containing or MPO-derived porous polymer material, wherein MPO denotes the vinyl methylene pyrrole oligomer. The MPO may be referred to as a “MPO monomer” in the present disclosures, as the MPO may be deemed a basic unit for forming the covalent organic frameworks. Covalent organic frameworks of the present disclosure can also be derived from and / or include multi-vinyl calix[4]pyrrole-containing (also referred to as “porphyrin-containing” in the present disclosure) porous polymer material, which may be abbreviated CP-containing or CP-derived polymer material, wherein CP denotes the multi-vinyl calix[4]pyrrole. Such polymer materials, which are covalent organic frameworks of the present disclosure, can be electron non-conductive and / or conductive. The electron non-conductive COFs can be used as low-cost adsorbents of Li+from SWRO brine. The electron conductive COFs can be used for organic cathodes of batteries.

[0062] Advantageously, the MPO-based monomers and CP-based monomers can be utilised in halogen-bonding-based free radical solid phase polymerization (XB -based free radical SPP), which enables the synthesis of the covalent organic frameworks (COFs) of the present disclosure. Such COFs can be used as adsorbents, which were tested to adsorb 21 mg of Li+per 1 g of adsorbent (2.1 wt% Li+adsorption) under simulated SWRO brine containing 0.34 ppm Li+, 20000 ppm Na+, and 2000 ppm Mg2+. This value (2.1 wt%) is one of highest record of Li+adsorption capacity in the field of Li+adsorption using the simulated SWRO brine. The maximum Li+adsorption capacity traditionally reported was 1.88 wt% using polyvinylpyrrolidone (PVP) electrospun fibers (loaded with hydrogen manganese oxide (HMO)) adsorbent.Hence, the COF adsorbents of the present disclosure with >1.88 wt% Li+adsorption capacity is advantageous. Traditionally, for the recovery of ions from SWRO brine, four main methods were considered, i.e., (a) solar evaporation, (b) electrodialysis, (c) membrane distillation crystallization, and (d) adsorption / desorption. The first three methods tend to be suitable only for high-concentration ions in brine. The adsorption / desorption method may be suitable for low-concentration ions such as Li+(0.34 mg / L) in brine. Thus, the COF adsorbents of the present disclosure can serve as efficient adsorbents of Li+.

[0063] Such COFs (adsorbent) showed selective Li+adsorption from a mixture of Li+and other ions; namely, the COF adsorbents of the present disclosure adsorbed Li+with high selectivity up to Li+ / Na+= 9 and Li+ / Mg2+> 1000 under the simulated SWRO brine condition containing 0.34 ppm Li+, 20000 ppm Na+, and 2000 ppm Mg2+.

[0064] Moreover, the COF adsorbents of the present disclosure can be easily recycled for use, and the electron-conductive COFs may be used as organic cathodes of batteries, such as in lithium ion and sodium ion batteries. The present COFs (adsorbents) are organic in the sense that they do not contain metals. Traditional metal-containing adsorbents have a potential problem that metals in the adsorbents may leak and contaminate both water and the recovered Li+. Thus, the organic (non-metal) adsorbents of the present disclosure are desirable.

[0065] Advantages of the present COFs involved in adsorption / desorption method also include providing a low capital investment and operational (energy) cost. Adsorbents can be integrated into membranes, which can be established as low-cost operational processes in water treatment and do not require costly heat treatment. Ions can be desorbed by adjusting pH, which can also be an established low-cost process exemplified by ion exchange. Desorption regenerates the original adsorbents, enabling recycled use of the adsorbents and resulting in further cost reduction.

[0066] Details of various embodiments of the covalent organic framework, its method of forming and use, and advantages associated with the various embodiments are now described below and / or with reference to the drawings. Where advantages of the embodiments and features are already demonstrated in one or more examples below and / or in the drawings, they shall not be reiterated for brevity.

[0067] In the present disclosure, there is provided for a covalent organic framework.

[0068] In various embodiments, the covalent organic framework may comprise polymer chains configured to form a covalently crosslinked polymer network, wherein each of the polymer chains may comprise monomeric units (or oligomeric units dervied from such monomeric units) each comprising a pyrrole-based moiety, wherein the pyrrole-based moiety is absent of any metal and may comprise a porphyrin moiety having an optionally substituted meso carbon, or a pyrrole moiety having an optionally substituted methylene group, or a mixture thereof. Porphyrins of the present disclosure may be interchangeably referred to as “calix[4]pyrrole”.

[0069] As mentioned above, it is described that the pyrrole-based moiety may comprise a porphyrin moiety. In general, it is understood that a pyrrole and a porphyrin are not equivalent. However, in the context of the present disclosure, the pyrrole-based moiety may be described as comprising the porphyrin moiety, as the pyrrole-based moiety may be a pyrrolic macrocycle comprising a porphyrin moiety, wherein the porphyrin moiety may be described as being structurally derived from pyrrole units, i.e., the porphyrin moiety comprises multiple pyrrole units linked to form a macrocyclic aromatic system. With this understanding, it is described in the present disclosure, in various embodiments, that the pyrrole-based moiety may comprise the porphyrin moiety.

[0070] In various embodiments, the covalent organic framework may comprise a linker comprising two halogens, wherein the linker, if present, renders a non-covalent halogen bond which couples one nitrogen bond of one pyrrole-based moiety and one halogen of the linker and another non-covalent halogen bond which couples one nitrogen of another pyrrole-based moiety and the other halogen of the linker, and the linker, when removed or if absent, renders a void which defines a pore in the covalently crosslinked polymer network.

[0071] It is to be noted that pyrrole has a five-membered aromatic ring with one nitrogen. Also, the compounds (COFs) can have multiple vinyl groups, and are thus able to form crosslinked (networked) polymer structures due to the multiple vinyl groups, as opposed to specifically linear (non-crosslinked) polymer structures. Advantageously, the crosslinked (networked) structure defines pores for adsorbing lithium ions.

[0072] In various embodiments, the porphyrin moiety may be derived from a compound represented by formula (I):(I)

[0073] wherein R and / or R’ may contain a polymerizable functional group; and / or wherein R, R’, R”, and R’” may be each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide. In various embodiments, where R and / or R’ may contain a polymerizable functional group, R” and R”’may be as defined above.

[0074] In the present disclosure, the term “polymerizable functional group” refers to a chemical moiety that contains a reactive site capable of undergoing chain-growth or step-growth polymerization to render a polymer through covalent bond formation. Non-limiting examples of the “polymerizable functional group” may include one or more carbon-carbon multiple bonds (such as vinyl or alkenyl groups), one or more strained rings capable of ring-opening polymerization, and / or one or more functional groups capable of condensation reactions.

[0075] In various embodiments, in relation to formula (I), R and R’ may form a ring structure having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide, and R” and R’”, may each independently be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde- containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide.

[0076] In various embodiments, the porphyrin moiety may be derived from a compound represented by formula (la):

[0077] wherein R1, R2, R3, R4, and / or R5may contain a polymerizable functional group; and / or wherein R1may be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, and wherein R2may be a bond or a methylene group or wherein R2is (i) alkylene, alkenylene, alkynylene, oxyalkylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted, or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group, and wherein R3, R4, and R may each independently be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group. In various embodiments, w'here R1, R2, R3, R4, and / or R5may contain a polymerizable functional group, R1, R2, R3, R4, and / or R5may include a carbon–carbon multiple bond (such as vinyl or alkenyl group), a strained ring capable of ring-opening polymerization, and / or a functional group capable of condensation reactions.

[0078] In various embodiments, in relation to formula (la), R1and R3may form a ring structure containing a (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, and wherein R2may be a bond or a methylene group or wherein R2may be (i) alkylene, alkenylene, alkynylene, oxyalkylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted, or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus- containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group, and wherein R4and R5may each independently be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen -containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group.

[0079] In various embodiments, the porphyrin moiety may be derived from one of the following compounds:

[0080] In various embodiments, the pyrrole-based moiety may comprise the porphyrin moiety and each of the monomeric units may be defined by one of the 5 following:

[0081] wherein n can be a positive integer. In various embodiments, n can be 1 or more, 2 or more, 5 or more, 10 or more, 20 or more, etc.

[0082] In various embodiments, the pyrrole moiety may be represented by formula (11):(II)

[0083] wherein R”” and / or R’”” may contain a polymerizable functional group; and / or wherein R””, R’””, R”””, and / or R’””” may be each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide. In various embodiments, where R”” and / or R’”” may contain a polymerizable functional group, R””” and R’””” may be as defined above. In various embodiments, where R”” and / or R’”” may contain a polymerizable functional group, R”” and / or R’”” may include a carbon-carbon multiple bond (such as vinyl or alkenyl group), a strained ring capable of ring-opening polymerization, and / or a functional group capable of condensation reactions.

[0084] In various embodiments, in relation to formula (II), R”” and R””’ may form a ring structure having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide, and R””” and / or R’””” may each independently be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide.

[0085] In various embodiments, the pyrrole -based moiety may comprise the pyrrole moiety and each of the monomeric units is represented by formula (Ila):(IIa)

[0086] wherein n can be a positive integer (n can be 1 or more, 2 or more, 5 or more, 10 or more, 20 or more, etc.), and wherein R6, R7, R8, R9, and / or R10may contain a polymerizable functional group. In various embodiments, where R6, R7, R8, R9, and / or R10may contain a polymerizable functional group, R6, R7, R8, R9, and / or R10may include a carbon-carbon multiple bond (such as vinyl or alkenyl group), a strained ring capable of ring-opening polymerization, and / or a functional group capable of condensation reactions.

[0087] In various embodiments, in relation to formula (Ila), n may be as defined above, and R6may be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, and wherein R7may be a bond or a methylene group or wherein R7may be (i) alkylene, alkenylene, alkynylene, oxyalkylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted, or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group, and wherein R8, R9, and R10may each independently be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containingaliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group.

[0088] In various embodiments, in relation to formula (Ila), n may be as defined above, and R6and R8form a ring structure containing a (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, and wherein R7may be a bond or a methylene group or wherein R7may be (i) alkylene, alkenylene, alkynylene, oxyalkylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted, or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group, and wherein R9and R10may each independently be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group.

[0089] In various embodiments, the pyrrole-based moiety may comprise the pyrrole moiety and each of the monomeric units is defined by one of the following:

[0090] wherein n can be a positive integer (n may be as defined in various embodiments above, wherein n can be 1 or more, 2 or more, 5 or more, 10 or more, 20 or more, etc.).

[0091] In various embodiments, the pyrrole-based moiety may comprise the pyrrole moiety and each of the monomeric units is defined by one of the following:

[0092] wherein n can be a positive integer (n can be 1 or more, 2 or more, 5 or more, 10 or more, 20 or more, etc.).

[0093] In various embodiments, the linker may comprise 1,4-diiodotetralluorobenzene, 1,2-diiodotetrafluorobenzene, 1,3-diiodotetralluorobenzene, 1,3,5-triiodotrifluorobenzene, 1,2,4-triiodotrifluorobenzene, 1,2,3-triiodotrifluorobenzene, 1,2,4,5-tetraiododifluorobenzene, 1,2-diiodobenzene, 1,3-diiodobcnzcnc, 1,4-diiodobcnzcnc, 1,3,5-triiodobcnzcnc, 1,2,4-triiodobcnzcnc, 1,2,3-triiodobenzene, 1,2,4,5-tetraiodobenzene, hexaiodobenzene, 1,2-diiodoethane, 1,3-diiodopropane, 1,4-diiodobutane, 1,5-diiodoheptane, 1,6-diiodohexane, or an α,ω-diiodoalkane.

[0094] In various embodiments, the covalent organic framework may be crystalline or amorphous.

[0095] The present disclosure also provides for a method for forming the covalent organic framework of various embodiments of the first aspect. Embodiments and advantages described for the present covalent organic framework of the first aspect can be analogously valid for the present method subsequently described herein, and vice versa. As the various embodiments and advantages have already been described above and in the examples demonstrated herein further below, they shall not be iterated for brevity.

[0096] In various embodiments, the method may comprise: providing a mixture comprising: a monomer (e.g., the CP monomer) or an oligomer (e.g., the MPO), wherein the monomer or the oligomer comprises a pyrrole-based moiety, wherein the pyrrole-based moiety is absent of any metal and comprises: a porphyrin moiety having an optionally substituted meso carbon, or a pyrrole moiety having an optionally substituted methylene group; a linker comprising two halogens; and a photo-initiator; co-crystallizing the monomer or the oligomer, with the linker, to form a co-crystal comprising the linker coupled to the monomer or the oligomer via halogen bond; and subjecting the co-crystal to solid phase polymerization to form a covalently crosslinked polymer network.

[0097] In various embodiments, the method may further comprise removing the linker to generate pores in the covalently crosslinked polymer network, wherein removing the linker may comprise washing the co-crystal with an alcohol after subjecting the co-crystal to solid phase polymerization.

[0098] In various embodiments, providing the mixture may comprise dissolving the monomer or the oligomer, the linker, and the photo-initiator, in an organic solvent to form the mixture.

[0099] In various embodiments, co-crystallizing the monomer or the oligomer, with the linker, may comprise removing the organic solvent from the mixture.

[0100] In various embodiments, providing the mixture may comprise forming the monomer or the oligomer, wherein forming the monomer or the oligomer may comprise: mixing a pyrrole with a carbonyl compound in the presence of a catalyst in a solvent to form the monomer and / or the oligomer.

[0101] In various embodiments, the carbonyl compound may comprise a ketone, an aldehyde, a carboxylic acid, an ester, or a mixture thereof.

[0102] In various embodiments, the catalyst may comprise methanesulfonic acid or trifluoroacetic acid.

[0103] In various embodiments, the monomer may comprise the porphyrin moiety, wherein the porphyrin moiety may be a compound represented by formula (1):R’ R R'"(I)

[0104] wherein R and / or R’ may contain a polymerizable functional group; and / or wherein R, R’, R”, and R’”, may be each independently be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldchydc-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide. In various embodiments, where R and / or R’ may contain a polymerizable functional group, R” and R”’may be as defined above.

[0105] In various embodiments, in relation to formula (I), R and R’ may form a ring structure having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, anamide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide, and R” and R’”, may each independently be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide.

[0106] In various embodiments, the monomer may comprise the porphyrin moiety, wherein the porphyrin moiety may be a compound represented by formula (Ta):

[0107] wherein R1, R2, R3, R4, and / or R5, may contain a polymerizable functional group; and / or wherein R1may be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, aphosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, and wherein R2may be a bond or a methylene group or wherein R2may be (i) alkylene, alkenylene, alkynylene, oxyalkylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted, or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group, and wherein R3, R4, and R5may each independently be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group. In various embodiments, w'here R1, R2, R3, R4, and / or R5may contain a polymerizable functional group, R1, R2, R3, R4, and / or R5may include a carbon–carbon multiple bond (such as vinyl or alkenyl group), a strained ring capable of ring-opening polymerization, and / or a functional group capable of condensation reactions.

[0108] In various embodiments, R1and R3may form a ring structure containing a (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygencontaining aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, and wherein R2may be a bond or amethylene group or wherein R2may be (i) alkylene, alkenylene, alkynylene, oxyalkylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted, or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde- containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group, and wherein R4and R5may each independently be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen -containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group.

[0109] In various embodiments, the monomer may comprise the porphyrin moiety comprising:

[0110] In various embodiments, the oligomer may comprise the pyrrole moiety, wherein the pyrrole moiety is represented by formula (II):(II)

[0111] wherein R”” and / or R’”” may contain a polymerizable functional group; and / or wherein R””, R’””, R”””, and / or R’””” may be each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide. In various embodiments, wherein R”” and / or R’”” may contain a polymerizable functional group, R””” and / or R”’”” may be as defined above.

[0112] Tn various embodiments, in relation to formula (IT), R”” and R””’ may form a ring structure having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde- containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide, and R””” and / or R’””” may each independently be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur- containing group, or an alkylhalide.

[0113] In various embodiments, the oligomer may comprise the pyrrole moiety, wherein the pyrrole moiety may be represented by formula (IIa):R6

[0114] wherein n can be a positive integer (n can be 1 or more, 2 or more, 5 or more, 10 or more, 20 or more, etc.); and wherein R6, R7, R8, R9, and / or R10may contain a polymerizable functional group; and / or wherein R4may be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic oraromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen -containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron -containing aliphatic or aromatic group, and wherein R7may be a bond or a methylene group or wherein R7may be (i) alkylene, alkenylene, alkynylene, alkoxylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogencontaining divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group, and wherein R8, R9, and R10may each independently be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group. In various embodiments, where R6, R7, R8, R9, and / or R10may contain a polymerizable functional group, R6, R7, R8, R9, and / or R10may include a carbon-carbon multiple bond (such as vinyl or alkenyl group), a strained ring capable of ring-opening polymerization, and / or a functional group capable of condensation reactions.

[0115] In various embodiments, in relation to formula (Ila), n may be as defined above, and R6and R8may form a ring structure containing a (i) hydrogen, hydroxyl, aldehye, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, an aromatic group, a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromaticgroup, or a boron-containing aliphatic or aromatic group, and wherein R7may be a bond or a methylene group or wherein R7may be (i) alkylene, alkenylene, alkynylene, alkoxylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group, and wherein R9and R10may each independently be (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group.

[0116] In various embodiments, the oligomer may comprise the pyrrole moiety comprising:

[0117] wherein n can be a positive integer as defined in various embodiments above.

[0118] In various embodiments, the oligomer may comprise the pyrrole moiety 5 comprising:H o H 4, OM: <nX A-b^n ", I Qi HH

[0119] wherein n can be a positive integer (n can be 1 or more, 2 or more, 5 or more, 10 or more, 20 or more, etc.).

[0120] In various embodiments, subjecting the co-crystal to solid phase polymerization may comprise exposing the co-crystal to ultraviolet light in an inert environment. In various embodiments, residual photo-initiator may be removed by washing with ethanol after UV exposure.

[0121] The term “hour” may be abbreviated as “hr” or “hrs” in the present disclosure.

[0122] The word “substantially” does not exclude “completely” e.g. a composition which is “substantially free” from Y may be completely free from Y. Where necessary, the word “substantially” may be omitted from the definition of the present disclosure.

[0123] In the context of various embodiments, the articles “a”, “an” and “the” as used with regard to a feature or element include a reference to one or more of the features or elements.

[0124] In the context of various embodiments, the tilde symbol the term “about”, and the term “approximately”, as applied to a numeric value encompasses the exact value and a reasonable variance. The variance may be ±20%, ±10%, ±5%, ±1%, ±0.5%, ±0.1%, etc.

[0125] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0126] Unless specified otherwise, the terms "comprising" and "comprise", and grammatical variants thereof, arc intended to represent "open" or "inclusive" languagesuch that they include recited elements but also permit inclusion of additional, unrecited elements.Examples

[0127] Examples of the present disclosure relate to the covalent organic frameworks. The covalent organic frameworks may be porous polymer materials, which may be derived from pyrroles (i.e., the MPO monomers) or porphyrins (i.e., the CP monomers). The porphyrins of the present disclosure may be interchangeably referred to as “calix[4]pyrrole”.

[0128] Various examples may relate to pyrrole -based covalent organic frameworks, which may be used for building blocks in the polymers and organic synthesis. Pyrroles have been connected to form conjugated polypyrroles and porphyrin macrocycles. Pyrroles have also been connected via non-conjugated sp3meso-carbon bridges to form non-conjugated pyrrole -containing polymers and calix[4]pyrrole macrocycles, having tailorable non-conjugated bridges for higher solubility, flexibility, and processability compared to rigid conjugated polypyrroles.

[0129] Both conjugated polypyrroles and non-conjugated pyrrole-bearing polymers and macrocycles may often leverage hydrogen bonding between the pyrrole NH and the external molecules and ions for capturing other compounds or molecules. Functionalization at the p-pyrrolic carbon for both polymers and the meso-carbon for non-conjugated polymers can further enhance molecular and ionic selectivity due to the tailored electronic affinity and pre -structured spatial conformation. Their integration into porous materials and crosslinked networks can further enhance selectivity and permeability of external molecules and ions. These materials can have broad applications in ion adsorption, catalysis, and water purification (removing organic pollutants such as dyes and ions such as Cr4+, Pb2+, and Cd2+from water).

[0130] Various examples may also relate to porphyrin (herein also termed “calix[4]-pyrrole”), which is a tetrapyrrolic macrocycle and can have a rigid and porous structure. The porous structure can effectively capture micropollutants and dyes. Porphyrin derivatives can be used as building blocks for supramolecular assemblies of the present disclosure. The reversible supramolecular approach, as observed in biological systems, is an effective way to construct well-ordered nanostructures,which facilitate efficient energy or electron transfer in light harvesting and catalysis. Non-covalent interactions such as hydrogen bonds, metal coordination, and π–π interactions are used to self-assemble porphyrin derivatives into a supramolecular architecture.

[0131] In summary, the “MPO monomers” and “CP monomers” were used in halogen-bond (XB)-assisted radical solid phase polymerization (SPP) to generate network polymers. The monomers were cocrystallized with additional XB linker molecules, and the obtained cocrystals were polymerized in the solid phase, for forming covalent organic frameworks of the present disclosure. Because of the alignment of such “monomers” in the cocrystals, the adjacent vinyl groups were close enough to undergo radical polymerization effectively, enabling the formation of highly crosslinked network polymers that are hardly obtainable in liquid (solution) phase polymerization. After removal of the liner, the obtained porous polymers served as highly efficient and selective adsorbents of lithium ion (Li+) from a model sea water reverse osmosis (SWRO) brine at a low Li concentration (0.34 mg L-1), adsorbing up to 21 mg of Li+(2.1 wt%) per 1 g of adsorbent, which is a very high Li+adsorption capacity in the field of Li+adsorption from SWRO brine.

[0132] The covalent organic frameworks, and its method of forming, are described in further details, by way of non-limiting examples, as set forth below.

[0133] Example 1A: Introductory Discussion for MPO-derived COFs

[0134] Herein, examples 1A to IE demonstrate for the first radical solid phase polymerization (SPP) of pyrrole-bearing vinyl monomers (FIG. 1A and FIG. 1B), wherein various new monomers with multiple vinyl groups were synthesized. The radical SPP enabled efficient formation of network structures that are inaccessible via radical liquid (solution) phase polymerization (LPP) (as demonstrated below). The resultant network polymers arc non-conjugatcd pyrrolc-containing polymers. Because of the presence of sp3-hybridized meso-carbon between pyrroles, use of this carbon to introduce spacers and functional groups and diversify the polymer and resultant porous structures were enabled.

[0135] Halogen-bond (XB)-assisted radical SPP of sterically unhindered mono-vinyl monomers, such as vinyl pyridines, were developed. The vinyl monomers and additional XB linkers w'ere combined to form solid cocrystals via XB, and theresultant alignment of the monomers facilitated polymer growth (propagation) to yield high-molecular-weight polymers. In the present examples, taking advantage of the efficient propagation, XB-assisted radical SPP of sterically hindered and multi-vinyl methylene pyrrole oligomer (MPO) monomers to generate network structures were conducted. Because of the alignment of MPO monomers in the cocrystals, the adjacent vinyl groups can be close enough to undergo effective polymerization (FIG. ID), which is hardly attainable in the liquid phase. Because the linker is non-covalently bonded with the monomer, the linker can be removed after the polymerization, providing pores (cavities) between MPO and CP units (FIG. ID).

[0136] The obtained network polymers (COFs) have high surface areas and freestanding interconnected pores, which may allow facile access and diffusion of external molecules and ions into the networks. Hence, the obtained COFs may serve as high-capacity adsorbents. In the present examples, lithium ion (Li+) adsorption from a model sea water reverse osmosis (SWRO) brine was used for studies. Adsorption can be a low-cost and low energy-consuming technique for Li+collection. Because of a high value of lithium, the collection of Li+from SWRO brine is an urgent demand in desalination and is a promising application. Notably, the obtained COFs exhibited the highest capacity of Li+adsorption from SWRO brine in this field and excellent adsorption selectivity of Li+from two other major metal ions (Na+and Mg2+) dominant in seawater. The obtained COFs were highly resistant to strong acids and bases, and thus durable for recycled use in the Li+collection. The network structures and pore sizes can be tuneable by configuring the monomers that are incorporated, which potentially allow selective adsorption of specific molecules and ions for wider applications. The materials involved are purely organic (free from toxic metals), which is hence environmentally attractive.

[0137] Example IB: Preparations of MPO-based Monomers

[0138] Fourteen multi-vinyl MPO monomers (FIG. IB), denoted MPO-AA, MPO-MAA, MPO-MAH, MPO-DMAEMA, MPO-DEGMA, MPO-MPC, MPO-CsK, MPO-C6K, MPO-PGA, MPO-C8K, MPO-TFEMA, MPO-C3A, MPO-C4K, MPO-CPK, MPO-C5K(Et), and MPO-CsK(CHO) were synthesized. MPO-CPK contains a cyclopropane group as a polymerizable group (viewed as a vinyl analogue). For brevity, the description and discussion of methods and characterisations from thisexample to example IE regarding MPO monomers can be applicable to CP monomers described in examples 2A to 2E.

[0139] The MPO monomers were synthesized in one pot at room temperature (22 °C) using no metal by linking pyrroles with vinyl-containing ketones (FIG. 1A). Ketone (1 eq.) and pyrrole (1.1 eq.) reacted in the presence of methane sulfonic acid (0.11 eq.) to generate a substituted MPO with a moderate yield (25-66%) in most cases (except 13% for MPO-TFEMA).

[0140] A MPO (used as a monomer) was combined with 1,4-diiodotetrafluorobenzene (I–C6F4–I) (used as an XB linker) to obtain a cocrystal (FIG. ID). A nitrogen (N) atom in the MPO unit (monomer) and an iodine (1) atom in the linker can form XB (FIG. ID). A monomer (2 eq. of pyrrole unit (hence 2 eq. of vinyl unit)), a linker (1 eq.), and a photo -initiator (2,2-dimethoxy-2-phenyl-acetophenone (DMPA)) (0.005 eq.) were dissolved in dichloromethane (solvent), where equimolar atoms of N and I were used for stoichiometric XB formation. The solvent was evaporated from the solution to obtain a three-component (monomer, linker, and initiator) cocrystal (called monomer cocrystal below) on a gram scale.

[0141] Example 1C: Results and Discussion on MPO-based Monomers

[0142] Free-radical SPP of the monomer cocrystals were carried out under UV light (λ = 365 nm) in an argon atmosphere for 16-65 hr at room temperature to obtain MPO-based network polymers (FIG. ID). DMPA were likely to be located between monomer / linker cocrystal grains. Upon UV irradiation, the radicals generated from DMPA (generated outside the grains) entered the monomer / linker grains through the grain surfaces. The propagation occured from one face to the center and to the counter face in the monomer / linker grains.

[0143] The monomer conversion reached approximately 100% in most cases except for MPO-MPC (71%) (FIG. 2, entries la- 14a (part a)). After the polymerization, the generated polymers were dispersed in ethanol and divided into ethanol-insoluble (network) polymers and ethanol-soluble (linear or branched (partly crosslinked)) polymers. The polymers were mainly insoluble network polymers (51-100%) in most cases except for MPO-MPC (22%) and MPO-MAH (46%) (Table 1, entries la-14a). Notably, MPO-C5K and MPO-PGA resulted in a 100% insoluble polymer (FIG. 2, entries 7a and 9a). The ethanol-soluble polymers were analyzed using polystyrene-calibrated gel permeation chromatography (GPC) (*N*,*N*-dimethyl formamide (DMF) eluent), showing moderately large molecular weights, i.e., peak-top molecular weights (Mp) of 6000-43000. These primary polymers were further crosslinked to form insoluble polymers (22-100%) as mentioned. The ethanol-soluble polymers contained low molecular weight oligomers, and the GPC baseline was not horizontal. Hence, it was not easy to accurately determine the number-average molecular weights and the peak-top Mp values were determined instead.

[0144] In the present examples, XB was used to align MPO monomers in the cocrystals to obtain network polymers (FIG. ID). Because of the alignment, the adjacent vinyl groups can be close enough to undergo effective polymerization, which was hardly attainable in solutions. For comparison, SPP of monomer / DMPA crystals without XB linker (FIG. 2, entries lb- 14b (part b)) and liquid (solution) phase polymerization (LPP) of monomer, DMPA, and dichloromethane (solvent) without XB linker (FIG. 2, entries lc-14c (part c)) were conducted. For both comparison polymerizations, no insoluble network polymers were generated in most cases (except MPO-MAA and MPO-PGA). A highlighting case was MPO-C5K, which resulted in a 100% insoluble polymer via SPP with the XB linker, a 100% soluble polymer via SPP without the XB linker, and even no polymerization via LPP (FIG. 2, entry 7). Thus, insoluble network polymers were solely obtainable via SPP with XB linker, highlighting the uniqueness of XB -based SPP for synthesizing MPO network polymers. Various MPO network polymers including those with functional hydroxyl (MPO-AA and MPO-MAA), dialkylamine (MPO-DMAEMA), ether (MPO-DEGMA), twitter ionic (MPO-MPC), alkyne (MPO-PGA), fluorinated (MPO-TFEMA), aldehyde (MPO-CsK(CHO)), and V- substituted alkyl (MPO-C5K(Et)) groups were obtained, demonstrating a large monomer scope for MPO network polymers, although non-functional PMO network polymers efficiently worked for Li+adsorption application as described below. Functional network polymers may find other applications in the future. MPO-CPK contains a cyclopropane group instead of a vinyl group as a polymerizable group. A possible polymerization mechanism is a radical ring-opening of the cyclopropane group. A high fraction (76%) of the insoluble polymer was generated (FIG. 2, entry 14a), which served as an efficient Li+adsorbent (as described below).

[0145] Presumably, when the substituents that were attached on MPO monomers were not very sterically hindered, vinyl groups in the monomer were easily polymerized. As the substituents become sterically hindered, a less number of the vinyl groups may be polymerized, forming split structures such as 2D sheet structures (FIG. 3). When the substituents were even more sterically hindered, an even less number of the vinyl groups may be polymerized to form more split linear (columnar) or branched (gyroid) structures.

[0146] After the linker removal, porous polymers were obtained. The first type of (smallest) pore (FIG. 4) was generated by the linker removal and was nano-sized space between MPOs which are covalently fixed via the polymerization (primary pores between MPOs). The second type of pore may be nano-sized space between 2D sheets or gyroids which are non-covalently associated via van der Waals interaction after the linker removal (interlayer nanopores). The third type of pores may be nanometer to micrometer- sized space among the polymer grains which correspond to the original cocrystal grains (intergrain micropores).

[0147] To probe the network structures, five selected polymers (purified polymers) were exfoliated as much as possible by dispersing the polymers (0.1 wt%) in DMF (99.9 wt%) under sonication for 1 hr and subsequent stirring for a few days. The five polymers were selected because they exhibited particularly high Li+adsorption capacity and selectivity as discussed below'. After exfoliation, sheet structures were observed for P(MPO-C5K), P(MPO-C6K), and P(MPO-CPK) using TEM (FIG. 5A to FIG. 5C). P(MPO-X) denotes a polymer of MPO-X monomer, where X is can be a substituent understood from FIG. IB. The observed free-standing individual sheets could give large intrinsic surface areas, w'hich were advantageous for achieving high adsorption capacity of Li+as discussed below. The AFM analysis (FIG. 6A and FIG.6B) of P(MPO-C5K) and P(MPO-CPK) showed that the sheet thickness was approximately 7.2 nm and 6.0 nm, respectively, which were larger than the assumed primary pore sizes (approximately 1-2 nm) (FIG. 3 and FIG. 4), indicating that each sheet actually consisted of multiple pore layers over the sheet thickness for these cases. A branched (gyroid-like) structure w'ith a periodic interval of approximately 3 nm was observed for more sterically hindered P(MPO-CgK) with using TEM (FIG.5D), as anticipated. A branched (gyroid-like) structure with a larger periodic intervalof 11-14 nm was also observed for a less sterically hindered P(MP0-C4K) using TEM (FIG. 5E). The monomer cocrystal lattice of MPO-C4K seemed to particularly fit the branched structure.

[0148] Example ID: Demonstration on Use of MPO Monomers

[0149] Li+adsorption of purified non-exfoliated network polymers was studied. The pyrrole units contain electron-donating nitrogen atoms and conjugated C=C bonds, which can coordinate Li+. Twelve polymers out of the fourteen polymers (FIG. 7) were studied because MPO-DEGMA and MPO-MPC were exfoliated or split into very small pieces during the Li+adsorption tests and could not be collected. The polymer (3 mg) was immersed in a model SWRO brine solution (3 L) containing Li+(0.34 mg L-1), sodium ion (Na+) (20000 mg L-1), and magnesium ion (Mg2+) (2000 mg L-1), which was sonicated for 1 hr and subsequently left overnight at room temperature for reaching adsorption equilibrium. The concentrations of Na+(20000 mg L-1) and Mg2+(2000 mg L-1) were much larger than that of Li+(0.34 mg L-1). The Li+concentrations in the aqueous solution phase were measured before and after the adsorption using inductively coupled plasma optical emission spectrometry (ICP-OES) and the adsorbed amount of Li+was calculated by subtracting the non-adsorbed amount of Li+from the initial amount of Li+(FIG. 7). Among the studied twelve polymers (adsorbents), P(MPO-C5K), P(MPO-C6K), P(MPO-C4K), P(MPO-C8K), and P(MPO-CPK) adsorbed as large as 21.0, 22.1, 23.5, 23.8, and 21.4 mg of Li+per 1 g of adsorbent, meaning 2.10, 2.21, 2.35, 2.38, and 2.14 wt% Li+adsorption per adsorbent, respectively (FIG. 8, entry la, and FIG. 7, entries 5, 6, 8, 11, and 12,). These values (2.10-2.38 wt% Li+adsorption) are among some of the highest records of adsorption capacity in the area of Li+adsorption using model SWRO brine solutions (FIG. 9). One of the highest records was 1.88 wt% for hydrogen manganese dioxide (HMO) adsorbent using natural seawater (with 0.17 mg L-1of Li+), and HMO was also tested and observed 1.29 wt% Li+adsorption under test condition using the model SWRO brine solution (with 0.34 mg L-1of Li+). A possible reason for the slightly lower adsorption in the test condition is a difference in the HMO morphology (HMO nanofiber (literature) and HMO powder (present test)), but the exact reason is unclear at this moment. Poly(3,5-diethynyl pyridine) (PPDA) adsorbent that exhibited high Li+adsorption from a concentrated Li+solution (1000 mg L-1) was also studied,but PPDA exhibited only 0.08 wt% Li+adsorption from the diluted Li+solution (0.34 mg L-1) (the present model SWRO brine) and did not suit the diluted system.

[0150] Also, markedly, P(MPO-C5K) showed excellent selective Li+adsorption from the mixed solution of Li+, Na+, and Mg2+. large Li+adsorption (2.10 wt% Li+adsorption) with little Na+(0.16 wt%) and Mg2+(0.0022 wt%) adsorption was observed despite the much higher concentrations of Na+and Mg2+than that of Li+in the model SWRO brine solution (FIG. 8, entry 1). The adsorbed amount ratios of Li+ / Na+and Li+ / Mg2+were as large as 13 (= 2.10 / 0.16) and 950 (= 2.10 / 0.0022), respectively. Because of the very high concentrations of Na+and Mg2+in the brine, the decrease in the Na+and Mg2+concentrations in the brine by the adsorption was negligibly small and unable to directly be detected using ICP-OES. Thus, the adsorption of Na+and Mg2+was indirectly detected from the desorbed amounts of Na+and Mg2+in the subsequent desorption process, because Na+and Mg2+were fully eluted out after the desorption process, as explained in detail below.

[0151] The observed selectivity is probably because the Li+---N coordination (distance = ca. 2.062 A) was stronger than the Na+-N (ca. 2.464 A) and Mg2+---N (ca. 2.123 A) coordination due to the high charge density (charge per atomic volume) of Li+. The observed 2.10 wt% Li+adsorption empirically means that 0.4 Li+ions were adsorbed per the pyrrole unit probably via Li+---N coordination and also Li+- C=C (conjugated carbon) coordination. The coordination of Li+with C=C was previously observed in electrochemical systems. The atomic diameter of Li+(0.31 nm) is small enough for Li+to be incorporated in MPO pores (approximately 1-2 nm (the smallest pores in FIG. 4)). Li+was also inserted (located) between the sheets (interlayer nanopores (FIG. 4)). The atomic diameters of Na+(0.38 nm) and Mg2+(0.32 nm) are also small enough, but very little incorporation was observed, suggesting weak coordination of Na+and Mg2+with P(MPO-C5K). Thus, P(MPO-C5K) had notably high adsorption capacity and excellent selectivity to Li+adsorption from the model SWRO brine.

[0152] P(MPO-CPK) exhibited even better selectivity (15 for Li+ / Na+and 2100 for Li+ / Mg2+) as well as slightly higher Li+adsorption (2.14 wt%) than P(MPO-C5K) (FIG. 7, entry 12). However, P(MPO-CPK) was not fully networked in its synthesis (24% soluble and 76% insoluble in ethanol) (FIG. 2, entry 14a). P(MPO-C5K) wasfully networked (100% insoluble in ethanol) (FIG. 2, entry 7a), offering the lowest synthetic cost of the network polymers. Hence, P(MPO-C5K) was chosen as a representative sample for the following adsorption-desorption recycle test (FIG. 8). P(MPO-C5K) was immersed in the model brine for 24 hr for adsorption of metal ions, taken out of the model brine, immersed in an aqueous HCl (1 M) solution for 24 hr for desorption of metal ions, rinsed with ethanol, and then sonicated in an aqueous ammonia (28%) solution for 30 min for neutralization prior to the next circle. It was observed that 2.10 wt% of Li+adsorption but only 0.0006 wt% of Li+desorption in the first cycle (FIG. 8, entry la), showing a significantly smaller amount of the desorbed Li+than that of the absorbed Li+. The Li binding affinity in the polymer might be too strong to fully release Li+even in the strongly acidic (1 M HCl solution) condition. In the second cycle, it was observed that another (additional) 2.07 wt% of Li+adsorption and again only 0.0005 wt% of Li+desorption (FIG. 8, entry 2a). In the third cycle, it was observed that another 2.11 wt% of Li+adsorption and only 0.0007 wt% of Li+desorption (FIG. 8, entry 3a).

[0153] The X-ray photoelectron spectroscopy (XPS) spectra of the adsorbent after the first, second, and third cycles (FIG. 10A) showed that the Li Is peak still remained even after the desorption process (acid treatment), meaning that Li+was hardly desorbed and the majority of Li+still remained in the absorbent. On the other hand, the scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) images of Na and Mg in the three cycles (FIG. 10B) demonstrated the presence (some adsorption) of Na+and Mg2+after the adsorption process but the complete disappearance (complete desorption) of Na+and Mg2+after the desorption process in each cycle. Thus, Na+and Mg2+if any adsorbed were nearly completely desorbed through the desorption process.

[0154] The Li+adsorption was approximately 2 wt% in each cycle and accumulated to approximately 6 wt% after the three cycles but was not 6 wt% at one time in the first cycle. This is probably because of the significant interference of the high concentrations of Na+(20000 mg L-1) and Mg2+(2000 mg L-1) in the model brine. These larger ions at high concentrations can easily block the nanopores near the polymer particle surface, preventing Li+from further diffusing deep into the innerporous area. In fact, without the desorption process, the adsorbent was not able to further adsorb Li+from the second cycle (FIG. 11).

[0155] Over ten cycles, the adsorption (hence desorption) of Na+and Mg2+were constantly as low as 0.0001-0.16 wt% for Na+and 0.0001-0.0022 wt% for Mg2+in each cycle (FIG. 8), keeping high selectivity in the Li+ / Na+(>13) and Li+ / Mg2+(>950) adsorption. The Li+adsorption gradually decreased from 1.97 wt% to 0.884 wt% from the fourth to seventh circles and was further lowered to 0.374-0.442 wt% in the eighth to tenth circles, probably because the pores were occupied with Li+over the cycles. After ten cycles, P(MPO-C5K) accumulated 13.0 wt% of Li+in total (cumulative Li+uptake) with keeping high Li+ / Na+and Li+ / Mg2+selectivity. For desorption, because of the strong binding affinity of Li+, Li+virtually started to desorb only from the fourth circle (FIG. 8, entry 4a) after the accumulated adsorption. The desorption in each cycle increased from 0.0007 wt% to 0.012 % from the third to seventh cycles but turned to decrease from 0.012 wt% to 0.0018 wt% from the seventh to tenth cycles partly because the amount of newly (relatively weakly) absorbed Li+(0.374-0.442 wt%) was small in the eighth to tenth cycles. The total recovery of Li+over the ten cycles was 0.3 % of all adsorbed Li+(= [cumulative 0.0385 wt% of desorbed Li+] / [cumulative 13.0 wt% of adsorbed Li+]).

[0156] The Li adsorption mechanism was further studied by the comparison between the Li adsorption of P(MPO-C5K) polymer and its original MPO-C5K monomer using the model brine. The Li adsorption in the monomer was 0.0136 wt% (FIG. 12), which was much lower than that (2.10 wt%) of the polymer (FIG. 8, entry la). The result indicates that the adsorption of Li+did not only occur in a single pyrrole unit but also occurred in sandwiched manners between two neighbouring pyrrole units by constructing network sheet structures and also between the generated sheet layers. Without the polymer network structures, not only Li+(0.0136 wt%) but also Mg2+(0.151 wt%) was unselectively adsorbed to the pyrrole unit in the monomer (FIG. 12). Thus, the polymer network structure also provided the high selectivity.

[0157] The surface area of non-exfoliated P(MPO-C5K) (after removal of linkers but not exfoliation) was determined using the BET method. The estimated specific surface area (*S*BET) was 1.13 m2g-1. The estimated pore size (*d*BET) was 2.0 nm, which is close to that (approximately 1-2 nm) of the assumed primary pore (the smallestpore in Figure 3)). Thermal stability of P(MPO-C5K) was studied with thermogravimetric analysis (TGA). The 5% weight-loss decomposition temperatures (*T*d,5%) was 238°C, demonstrating high thermal stability. The high thermal stability and chemical resistance to acid and base (as observed in adsorption-desorption recycle test) can be beneficial for various adsorption applications.

[0158] Example IE: Further Discussion - Applicable Monomers

[0159] FIG. 13 shows the structure of an MPO-based monomer that can be used. The MPO-based monomer shown in FIG. 13 contain multiple polymerizable vinyl (C=C) groups. The vinyl group can be replaced by cyclopropane. MPO-based monomer can contain 1 polymerizable vinyl group, more preferably 2 polymerizable vinyl groups, further preferably 3 polymerizable vinyl groups, or most preferably 4 or more polymerizable vinyl groups.

[0160] R6, R7, R8, R9, and R10in FIG. 13 can be any atoms or any groups suitable for the context of the present disclosure.

[0161] R6can be hydrogen (H) and methyl group (CH3). R6can be halogen such as fluorine, chloride, bromide, and iodide and oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group, other group such as hydroxyl group, aldehyde group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid, alkoxy group, ester group, ketone group, ether group, epoxide group, amide group, and ionic group. R6can be C2 to C20 linear, branched, and cyclic alkyl, alkene, and alkyne group that is unsubstituted or substituted by one or more of halogen such as fluorine, chloride, bromide, and iodide and oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group, or other group such as hydroxyl group, aldehyde group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid, alkoxy group, ester group, ketone group, ether group, epoxide group, amide group, ionic group, and unsubstituted or substituted aromatic or heteroaromatic ring system. R6can be aromatic ring system that is unsubstituted or substituted by one or more ofhalogen such as fluorine, chloride, bromide, and iodide and oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group, or other group such as hydroxyl group, aldehyde group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid, alkoxy group, ester group, ketone group, ether group, epoxide group, amide group, and ionic group.

[0162] In certain non-limiting examples, R7can be eliminated, and the vinyl (C=CR1) group can be directly attached to the porphyrin ring. R7can be CH2 group. R7can be oxygen atom and sulfur atom. R7can be oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group such as unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, ester group, ketone group, ether group, epoxide group, amide group, unsubstituted or unsubstituted aromatic or heteroaromatic ring system, and ionic group. R7can be C2 to C20 linear, branched, and cyclic alkyl, alkene, and alkyne group that is unsubstituted or substituted by one or more of halogen such as fluorine, chloride, bromide, and iodide and oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group such as hydroxyl group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid, alkoxy group, ester group, ketone group, ether group, epoxide group, amide group, ionic group, and unsubstituted or substituted aromatic or heteroaromatic ring system.

[0163] R8, R9, and R10can independently be hydrogen (H), methyl group (CH3), ethyl (C2H4), heptyl (C5H10), vinyl (C=C), cyclopropyl, ether, and oxyketone (O-(C=O)) group. R8, R9, and R10can be halogen such as fluorine, chloride, bromide, and iodide and oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group, or other group such as hydroxyl group, aldehyde group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid,alkoxy group, ester group, ketone group, ether group, epoxide group, amide group, and ionic group. R8, R9, and R10can be C2 to C20 linear, branched, and cyclic alkyl, alkene, and alkyne group that is unsubstituted or substituted by one or more of halogen such as fluorine, chloride, bromide, and iodide and oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group, or other group such as hydroxyl group, aldehyde group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid, alkoxy group, ester group, ketone group, ether group, epoxide group, amide group, ionic group, and unsubstituted or substituted aromatic or heteroaromatic ring system. R8, R9, and R10can be aromatic ring system that is unsubstituted or substituted by one or more of halogen such as fluorine, chloride, bromide, and iodide and oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group, or other group such as hydroxyl group, aldehyde group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid, alkoxy group, ester group, ketone group, epoxide group, amide group, and ionic group.

[0164] R6and R8can be covalently connected to from a cyclic structure.

[0165] The monomers in examples 1A to IE are not limited to those described above, other porphyrin compounds that can be polymerized in radical polymerization can also be applicable.

[0166] Example 2A: Introductory Discussion for CP-derived COFs

[0167] Examples 2A to 2E demonstrate the first radical solid-phase polymerization (SPP) of porphyrin-based monomers, which successfully enables efficient formation of network polymer structures that are inaccessible via radical liquid phase polymerization (LPP) at room temperature without using metals. Various porphyrinbased monomers bearing multiple (four) vinyl groups were synthesized relatively easily in one pot under a mild condition at room temperature without using metals with relatively high yields (50-100%) in most cases (FIG. 1C and FIG. IE). Themonomers contained multiple vinyl groups and provided 2D or 3D network polymers via SPP (FIG. 14A).

[0168] In these examples, the efficient propagation as mentioned in example 1 A was relied on and porphyrin-based monomers were used in the XB-assisted free-radical SPP for facilitating chain growth (network formation) of such sterically hindered multi-vinyl monomers. Because of the alignment of porphyrin-based monomers in the cocrystals, the adjacent C=C groups can be close enough and minimize the steric hindrance to undergo effective polymerization (FIG. 14A), which was hardly attainable in liquid phase. This opens up unprecedented efficient syntheses of porphyrin-based network polymers via radical polymerization. After the polymerization, the XB linker was removed, providing network porphyrin-based polymers with regulated nanometer-size pores (FIG. 14A). Notably, the network structures such as 3D gyroid structures and multi-layered 2D sheets and the pore sizes can be modulated by the monomer structures (substituents in the porphyrin-based monomers).

[0169] The obtained polymers (i.e., the COFs) had the same resultant properties and characteristics as described in example 1A (porous network polymers with freestanding interconnected pores, low-cost and effective for Li+adsorption and selectivities over other ions, highly resistant against acids and bases, and insoluble in most solvents and thus durable for recycled use, as well as having configurable pore sizes, metal free and environmentally friendly, etc.) As the advantages and uses are described in example 1 A, they shall not be reiterated for brevity.

[0170] Example 2B: Preparations of CP-based Monomers and their Cocrystals via XB

[0171] Fourteen porphyrin-based tetra-vinyl monomers (FIG. 1C), i.e., PPR-AA, PPR-MAA, PPR-MAH, PPR-DMAEMA, PPR-DEGMA, PPR-MPC, PPR-C5K, PPR-C6K, PPR-PGA, PPR-C8K, PPR-TFEMA, PPR-C3A, PPR-C4K, PPR-CPK, PPR-C5K(Et), and PPR-C5K(CHO) were synthesized. These monomers are also referred to as multi-vinyl CP monomers, which may be termed CP-AA, CP-MAA, CP-MAH, CP-DMAEMA, CP-DEGMA, CP-MPC, CP-C5K, CP-C6K, CP-PGA, CP-C8K, CP-TFEMA, CP-C3A, and CP-C4K, CP-CPK, CP-C5K(Et), and CP-C5K(CHO) respectively, in the present disclosure.

[0172] For synthesis, the same one pot method described in example IB was used, except this was carried out for 18 hrs to generate a porphyrinogen intermediate. An excess of triethylamine (0.17 eq.) was subsequently added, yielding the aimed porphyrin-based tetra-vinyl monomers in moderate to high yields (30-100%) in most cases (except 13% for PPR-TFEMA).

[0173] Cocryslals were prepared in the same manner described in example IB, wherein CP monomers were used instead of MPO-based monomers. In these examples, 0.01 eq. of DMPA was used instead of 0.005 eq.

[0174] Example 2C: Results and Discussion on CP-based Monomers

[0175] Free-radical SPP of the monomer cocrystals were carried in the same manner described in example 1C, but in this instance to obtain porphyrin-based network polymers (FIG. IE).

[0176] Similarly, the other monomers and linkers wered studied for SPP. The obtained polymers were purified by washing with ethanol. The obtained polymers were divided into two fractions, namely, polymers insoluble and soluble in ethanol. The linker was also soluble in ethanol and was removed from the ethanol-soluble polymer using hexane (non-solvent of the ethanol- soluble polymer). Due to the crosslinked network structures, a part to full portion of the polymers (22-100% (FIG.15)) were insoluble in organic solvents. The SPP of PPR-C5K resulted in a 100% monomer conversion and generated a 100% insoluble polymer (FIG. 15 (entry 7)), for example. The soluble polymers (0-78% (FIG. 15)) were non-crosslinked liner or partly crosslinked branched polymers. The soluble polymers were analyzed using polystyrene-calibrated GPC (DMF eluent) to determine the molecular weights (FIG.1C and FIG. 15). The soluble polymers had moderately large molecular weights, i.e., peak-top molecular weights (Mp) of 6000-43000, demonstrating the formation of polymers. These primary polymers were further crosslinked to form insoluble polymers (22-100% (FIG. 15)) for all cases, as mentioned. The molecular weight distribution of the soluble polymer was broad towards the low molecular weight side, and the GPC baseline was not horizontal for all cases. Thus, the Mp values were determined instead of the number average molecular weights and dispersities.

[0177] In the present examples, XB was used to align the porphyrin-based monomers in the cocrystals to obtain network polymers (FIG. 14A). Because of thealignment, the adjacent C=C groups can be close enough and minimize the steric hindrance to undergo effective polymerization, which is hardly attainable in solutions. For comparison, SPP without the XB linker (SPP of pure monomer mono-crystals) and liquid phase polymerization of pure monomer without the XB linker in solution were also conducted (FIG. 15). For all cases, none or the only small fraction (13% for PPR-MAA and 0% for all other cases (FIG. 15)) of the obtained polymers were insoluble crosslinked polymers, and most of the obtained polymers (87% for PPR-MAA and 100% for all other cases (FIG. 15)) were soluble. A highlighting case was PPR-C5K, which resulted in 100% insoluble polymer via SPP with the XB linker, 100% soluble polymer via SPP without the XB linker, and even no polymerization via solution (liquid) phase polymerization (FIG. 15 (entry 7)). Thus, insoluble crosslinked polymers were solely obtainable via SPP with the XB linker, highlighting the uniqueness and advantage of the use of XB-based SPP for synthesizing crosslinked porphyrin-based network polymers. This demonstrates the synthesis of 3D porphyrinbased polymers via such radical polymerization.

[0178] When the substituents attached on the porphyrin ring are not largely sterically hindered, all of the four vinyl groups in the porphyrin monomer may be polymerized, ideally forming 3D close-packing columnar network structures (FIG.16C). As the substituents become sterically hindered, a less number (two to three) of the vinyl groups may be polymerized, forming split structures such as 2D sheet (layer) structures (FIG. 16B). Sheets are likely formed when two vinyl groups in the monomer at the opposite positions are polymerized, and some sheets may further be connected via the polymerization of the third vinyl group in part. When the substituents are even more sterically hindered, an even less number (one to two) of the vinyl groups may be polymerized to form branching (gyroid) or linear (columnar) single chain structures (FIG. 16A to FIG. 16C).

[0179] After the SPP and XB linker removal, porous polymers were obtained. The first type of (smallest) pore (FIG. 17) is the nano-sized porphyrin ring cavity. The second type of pore (FIG. 17) is nano-sized space between porphyrin-porphyrin planner layers that are fixed covalently by the polymerization. The third type of pore (FIG. 17) may be nano-sized space among columns, between sheets, and through gyroid that are fixed covalently by the polymerization or noncovalently via van derWaals interaction after the linker removal. The fourth type of pores (FIG. 17) may be nanometer to micrometer- sized space among the polymer grains that originally correspond to the cocrystal grains.

[0180] To probe the porous structures, the obtained purified polymers (0.1 wt%) were exfoliated as much as possible by dispersing the polymers in DMF (99.9 wt%) under sonication for 1 hr and subsequent stirring for a few days. After exfoliation, sheet structures were observed for P(PPR-C5K), P(PPR-C6K), and P(PPR-CPK) using AFM (FIG. 18A and FIG. 18B) and TEM (FIG. 19A to FIG. 19F). P(PPR-X) denotes a polymer of PPR-X monomer, where X indicates a chemical structure as given in FIG. 1C. According to the AFM images, the thickness of the sheet was 1.8-7.2 nm and 6.0 nm for P(PPR-C5K) and P(PPR-CPK), respectively, which corresponded to 3-12 and 10 pieces of planar porphyrin layer thickness (approximately 0.6 nm). The sheet structure was also observed for P(PPR-C5K), P(PPR-C6K), and P(PPR-CPK) using TEM (FIG. 19A to FIG. 19C). These free-standing individual sheets could retain large intrinsic surfaces, which were advantageous for achieving maximum adsorption capacity of Li+as discussed below. 3D network (gyroid-like) structures were observed for more sterically hindered P(PPR-C8K) and P(PPR-MPC) using TEM (FIG. 19D and FIG. 19E). The diameter of the networking structure was approximately 3 and 8-10 nm for P(PPR-C8K) and P(PPR-MPC), respectively. A gyroid-like structure (with a diameter of 11-14 nm) was also observed for a less sterically hindered P(PPR-C4K) using TEM (FIG. 19F). Its monomer cocrystal structure renders a gyroid like- structure in this particular case.

[0181] Thermal stability of a few selected polymers, i.e., P(PPR-MAA), P(PPR-CPK), and P(PPR-C5K) polymers was analyzed with thermogravimetric analysis (TGA). P(PPR-CPK) and P(PPR-C5K) were selected because they exhibited particularly high Li+adsorption capacity and selectivity as discussed below. The 5% weight-loss decomposition temperatures (Td,5%) of P(PPR-MAA), P(PPR-CPK), and P(PPR-C5K) were 208, 237, and 238°C, respectively, demonstrating their high thermal stability. The high thermal stability and chemical resistance to acid and base (as described below) of these porous materials can be beneficial to future possible fabrication of recyclable adsorption membranes via embedment of these porous materials in membranes.

[0182] Example 2D: Demonstration on Use of CP Monomers

[0183] The same studies described in example ID were carried out for CP monomers, i.e,. Li+adsorption of non-exfoliated polymers (purified ethanol-insoluble fraction polymers). Twelve polymers out of the fourteen synthesized polymers because PPR-DEGMA and PPR-MPC were exfoliated or split into very small pieces during the Li+adsorption tests. The porphyrin-based polymers contain electrondonating nitrogen atoms and conjugated C=C bonds in the porphyrin ring, which can coordinate metal cations. Similar to example ID, the Li+concentrations in the aqueous solution phase before and after the adsorption were measured using inductively coupled plasma optical emission spectrometry (ICP-OES) and the adsorbed amount of Li+was calculated by subtracting the non-adsorbed amount of Li+from the initial amount of Li+(FIG. 20). Among the studied twelve polymers (adsorbents), P(PPR-C5K), P(PPR-C6K), P(PPR-C4K), P(PPR-C8K), and P(PPR-CPK) adsorbed as much as 21.0, 22.1, 23.5, 23.8, and 21.4 mg of Li+per 1 g of adsorbent, meaning 2.10, 2.21, 2.35, 2.38, and 2.14 wt% Li+adsorption per adsorbent, respectively (FIG. 8, entry la, and FIG. 20, entries 5, 6, 8, 11, and 12). These values (2.10-2.38 wt% Li+adsorption) are among the highest records of adsorption capacity in the area of Li+adsorption using model SWRO brine solutions (FIG. 21). HMO was also tested and 1.46 wt% Li+adsorption using a model SWRO brine solution was observed.

[0184] Also, markedly, P(PPR-C5K) showed excellent selective Li+adsorption from a mixed solution of Li+, Na+, and Mg2+in the studied model SWRO brine solution. It was virtually observed that only Li+adsorption (2.10 wt% Li+adsorption) with very little Na+(0.30 wt%) adsorption and Mg2+(0.0022 wt%) adsorption despite the much higher concentrations of Na+and Mg2+than that of Li+ in the model SWRO brine solution (FIG 8, entries la-lc). The adsorbed amount ratios of Li+ / Na+and Li+ / Mg2+were as large as 7 (= 2.10 / 0.30) and 950 (= 2.10 / 0.0022), respectively. For the determination of the adsorbed amounts of Na+and Mg2+, because of the significantly higher concentrations of Na+and Mg2+in the brine solution, the decrease in the Na+and Mg2+concentrations in the brine solution before and after the adsorption was negligibly small and could not be detected using ICP-OES (out of the detection limit of ICP-OES). Thus, the adsorption of Na+and Mg2+were unable to be detecteddirectly, but were instead indirectly detected from the desorbed amounts of Na+and Mg2+in the subsequent desorption process, because Na+and Mg2+were fully eluted out after the desorption process, as explained in detail below.

[0185] The observed selectivity is probably because the Li+- N coordination (distance = ca. 2.062 A) was stronger than the Na+---N (ca. 2.464 A) and Mg2+---N (ca. 2.123 A) coordination due to the higher charge density of Li+and also because porphyrin rings (or conjugated carbons) might have Li+capacities as observed in electrochemical systems. The atomic diameter of Li+(0.31 nm) is small enough for Li+to be incorporated in porphyrin pores (ca. 0.485 nm) and in single-chain 3D network pores (with < 3.0 nm pore sizes according to the TEM analysis) and to be inserted between physically associated porphyrin 2D interlayers (via van der Waals force), rationalizing the Li+adsorption. The atomic diameters of Na+(0.38 nm) and Mg2+(0.32 nm) are also small enough, but very little incorporation was observed, suggesting weak coordination of Na+and Mg2+with P(PPR-C5K). Thus, P(PPR-C5K) had the notably high adsorption capacity of Li+and excellent adsorption selectivity to Li+adsorption in model SWRO brine solution. The observed 2.1 wt% Li+adsorption (FIG. 8, entry la) empirically means 2 Li+ions are adsorbed per the monomer unit (PPR-C5K unit), while the observed 0.3 wt% Na+adsorption and 0.0022 wt% Mg2+adsorption (FIG. 8, entries lb and 1c) empirically mean only 0.07 Na+ions and 0.0005 Mg2+ions are adsorbed per the monomer unit, showing high selectivity.

[0186] P(PPR-CPK) exhibited even slightly higher Li+adsorption (2.14 wt%) and even slightly better selectivity (15 for Li+ / Na+and 2100 for Li+ / Mg2+) (FIG. 20). While P(PPR-CPK) was only partially insoluble in ethanol (24% soluble and 76% insoluble in ethanol), P(PPR-C5K) was completely (100%) insoluble in ethanol, offering the lowest synthetic cost of the insoluble network polymers and ease of recovering after adsorption. Hence, P(PPR-C5K) was chosen as a representative sample for a further adsorption-desorption recycle test. P(PPR-C5K) (adsorbent) was immersed in the model brine for 24 hrs. After adsorption, the adsorbent was taken out of the model brine solution, immersed in an aqueous HCl (1 M) solution for desorption of metal ions for 24 hrs, rinsed with ethanol, and sonicated in ammonia solution (28 % in water) for 30 min for neutralization prior to the next circle (FIG. 8). It was observed that 2.1 wt% of Li+adsorption but only 0.0006 wt% of Li+desorptionin the first cycle (FIG. 8, entry la), where only 0.006 mg of Li+was desorbed out of 2.1 mg of the adsorbed lithium per 1 g of the adsorbent, showing significantly smaller amount of the desorbed Li+than that of the absorbed Li+. The Li binding affinity in the polymer might be too strong to fully release Li+even in the strongly acidic (1 M HCl solution) condition. In the second cycle, it was observed that another (additional) 2.07 wt% of Li+adsorption and again only 0.0005 wt% of Li+desorption, and in the third cycle, it was observed that a further 2.11 wt% of Li+adsorption and only 0.0007 wt% of Li+desorption (FIG. 8, entries 2a and 3a).

[0187] The XPS spectra of the adsorbent after the first, second, and third cycles (FIG. 22) showed that the Li Is peak at 52.5 eV (binding energy) still remained even after the desorption process (acid treatment) in all cycles, demonstrating that Li+was hardly desorbed and the majority of Li+still remained in the absorbent under the acid treatment. On the other hand, the SEM-EDS images of Na and Mg in the cycles (FIG.22) demonstrated the presence (some adsorption) of Na+and Mg2+after the adsorption process but the complete disappearance (complete desorption) of Na+and Mg2+after the desorption process in each cycle. Thus, Na+and Mg2+, if any were adsorbed, were nearly completely desorbed through the desorption process (acid treatment).

[0188] Li+was adsorbed approximately 2 wt% in each cycle and accumulated approximately 6 wt% after the three cycles but was not able to adsorb 6 wt% in the first cycle. This is probably because of the significant interference of the high concentrations of Na+(20000 mg L-1) and Mg2+(2000 mg L-1) in the model brine. These larger ions at high concentrations easily block the nanopores near the polymer particle surface, preventing Li+from further diffusing deep into the inner porous area. In fact, without the desorption process, the adsorbent was not able to further adsorb Li+from the second cycle (FIG. 23).

[0189] Over ten cycles, the adsorption (hence desorption) of Na+and Mg2+were constantly as low as 0.0001-0.34 wt% for Na+and 0.0001-0.0022 wt% for Mg2+in each cycle (FIG. 8), keeping high selectivity in the Li+ / Na+(>5) and Li+ / Mg2+(>950) adsorption. The Li+adsorption in each cycle remained as high as 1.97-2.11 wt% in the first four circles. The Li+adsorption gradually dropped from 1.97 wt% to 0.884 wt% from the fourth to seventh circles and was significantly lowered to 0.374-0.442 wt% in the eighth to tenth circles. The decrease in the Li+adsorption can be becausethe pores were gradually occupied with Li+over the cycles. After ten cycles, P(PPR-C5K) accumulated 13.0 wt% of Li+in total (cumulative Li+uptake) with noticeably high Li+ / Na+and Li+ / Mg2+selectivity. For desorption, because of the strong binding affinity of Li+- • • N coordination, Li+only started to desorb from the fourth circle (FIG.8, entry 4a) after accumulated adsorption, and the total recovery of Li+over the ten cycles was 0.3 % of all adsorbed Li+(= [cumulative 0.0385 wt% of desorbed Li+] / [cumulative 13.0 wt% of adsorbed Li+]). The desorption in each cycle increased from 0.0007 wt% to 0.012 wt% from the third to seventh cycles (corresponding to 0.03 % to 1.4 % recovery of Li+in each cycle) and turned to decrease to 0.0018 wt% (corresponding to 0.5 % to 1.4 % recovery of Li+in each cycle) from the seventh to tenth cycles, probably because the amount of absorbed Li+was relatively small (0.374-0.442 wt%) in the eighth to tenth cycles, leading to the proportionally low amount of desorbed Li+, whereas the recovery of Li+in each circle remained similar (0.5-1.4 %). Considering the relatively low desorption efficiency, a possible practical way to collect all adsorbed Li+may be to bum the Li+-adsorbed adsorbent for removing all polymer components. This way may be practically considered due to the large amount of Li+that can be adsorbed, high value of lithium, and relatively low cost of monomers and ease of polymer synthesis.

[0190] The Li adsorption mechanism was further studied by the comparison between the Li adsorption of P(PPR-C5K) polymer and its original porphyrin-C5K monomer using the model brine. The Li adsorption in the monomer was 0.0136 wt% (FIG. 24), which was much lower than that (2.10 wt%) of the polymer (Table 3, entry la). The result indicates that the adsorption of Li+did not only occur in a single porphyrin ring but also occurred in a sandwiched manner between two neighbouring porphyrin rings by constructing layered polymer porous network structures. Without the layered polymer porous network structures, not only Li+but also Na+and Mg2+might be unselectively adsorbed in a single porphyrin ring (in a monomer). The layered polymer porous network structure would provide the observed high selectivity, resulting in the significantly enhanced Li+adsorption.

[0191] Example 2E: Further Discussion - Applicable Monomers

[0192] FIG. 25 shows the structure of porphyrin-based (CP-based) monomer that can be used. The CP-based monomer shown in FIG. 25 contain multiplepolymerizable vinyl (C=C) groups. The vinyl group can be replaced by cyclopropane. MPO-based monomer can contain 1 polymerizable vinyl group, more preferably 2 polymerizable vinyl groups, further preferably 3 polymerizable vinyl groups, or most preferably 4 or more polymerizable vinyl groups. R1, R2, and R3in FIG. 25 can be any atoms or any groups as described in example IE.

[0193] In general, various examples may relate to a covalent organic framework (COF) comprising monomeric units of porphyrin crosslinked to form a polymer network, wherein each monomeric unit of porphyrin comprises a core which is absent of a metal, wherein each monomeric unit of porphyrin comprises methine bridges which are substituted, wherein each methine bridge comprises a substituent which is bonded to a linker comprising a halogen, and wherein one monomeric unit of porphyrin is crosslinked to another monomeric unit of porphyrin via the linker, wherein the monomeric units of porphyrin are polymerizable in radical polymerization, preferably free-radical solid-phase polymerization. In various embodiments, each monomeric unit may be represented by a chemical structure as shown in FIG. 25, wherein R1, R2, R3, R4, and R5in FIG. 25 can be any atoms or any groups suitable for the context of the present disclosure.

[0194] In various examples of FIG. 25, R1may comprise hydrogen (H) or methyl group (CH3). In various examples, R1may comprise a halogen such as fluoride, chloride, bromide, or iodide. In various examples, R1may comprise oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group, or other group such as hydroxyl group, aldehyde group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid, alkoxy group, ester group, ketone group, ether group, epoxide group, amide group, or ionic group.

[0195] In various examples of FIG. 25, R1may comprise C2 to C20 linear, branched, and cyclic alkyl, alkene, and alkyne group that is unsubstituted or substituted by one or more of halogen such as fluorine, chloride, bromide, and iodide and oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group, or other group such as hydroxyl group, aldehyde group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted orunsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid, alkoxy group, ester group, ketone group, ether group, epoxide group, amide group, ionic group, and unsubstituted or substituted aromatic or heteroaromatic ring system.

[0196] In various examples of FIG. 25, R1may comprise an aromatic ring system that is unsubstituted or substituted by one or more of halogen such as fluoride, chloride, bromide, and iodide and oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group, or other group such as hydroxyl group, aldehyde group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid, alkoxy group, ester group, ketone group, ether group, epoxide group, amide group, or ionic group.

[0197] In various examples of FIG. 25, R2may comprise a direct bond and the vinyl (C=CR1) group is directly attached to the porphyrin ring.

[0198] In various examples of FIG. 25, R2comprise a CH2 group, an oxygen atom or a sulfur atom, or a oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group such as unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, ester group, ketone group, ether group, epoxide group, amide group, unsubstituted or unsubstituted aromatic or heteroaromatic ring system, or ionic group.

[0199] In various examples of FIG. 25, R2may comprise a C2 to C20 linear, branched, and cyclic alkyl, alkene, and alkyne group that is unsubstituted or substituted by one or more of halogen such as fluoride, chloride, bromide, and iodide and oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group, or other group such as hydroxyl group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid, alkoxy group, ester group, ketone group, ether group, epoxide group, amide group, ionic group, and unsubstituted or substituted aromatic or heteroaromatic ring system.

[0200] In various examples of FIG. 25, R3may comprise hydrogen (H), methyl group (CH;). ethyl (C2H4), heptyl (C5H10), vinyl (C=C), cyclopropyl, ether, or oxyketone (O-(C=O)) group.

[0201] In various examples of FIG. 25, R3, R4, and R5may comprise a halogen such as fluoride, chloride, bromide, or iodide, or a oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group, or other group such as hydroxyl group, aldehyde group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid, alkoxy group, ester group, ketone group, ether group, epoxide group, amide group, or ionic group.

[0202] In various examples of FIG. 25, R3, R4, and R may comprise C2 to C20 linear, branched, and cyclic alkyl, alkene, and alkyne group that is unsubstituted or substituted by one or more of halogen such as fluoride, chloride, bromide, and iodide and oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group, or other group such as hydroxyl group, aldehyde group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid, alkoxy group, ester group, ketone group, ether group, epoxide group, amide group, ionic group, and unsubstituted or substituted aromatic or heteroaromatic ring system.

[0203] In various examples of FIG. 25, R3, R4, and R5may comprise an aromatic ring system that is unsubstituted or substituted by one or more of halogen such as fluoride, chloride, bromide, and iodide and oxygen-, sulfur-, nitrogen-, phosphorus-, silicon-, and boron-containing aliphatic and aromatic group, or other group such as hydroxyl group, aldehyde group, carboxylic acid group, thiol group, sulfonic acid, unsubstituted or substituted amino group, unsubstituted or unsubstituted phosphorus group, unsubstituted or substituted silane or alkoxy silane group, unsubstituted or substituted boron group, boronic acid, alkoxy group, ester group, ketone group, epoxide group, amide group, or ionic group.

[0204] In various examples of FIG. 25, R1and R3can be covalently connected to form a cyclic structure.

[0205] Tn various examples relates to FTG. 25, there is a method for forming the covalent organic framework, the method may comprise forming a porphyrin-based monomer comprising methine bridges which are substituted, and mixing the porphyrin-based monomer and a linker to form the covalent organic framework, wherein the porphyrin- based monomer remains in a solid phase, and wherein the linker may comprise a halogen.

[0206] Example 3: Further Examples

[0207] P(MPO-C5K(Et)) and P(MPO-C5K(CHO)) were used for the adsorption-desorption recycle test (FIG. 28 and FIG. 29). Also, real SWRO brine was used for adsorption. P(MPO-C5K(Et)) and P(MPO-C5K(CHO)) was immersed in the real SWRO brine for 24 hr for adsorption of metal ions, taken out of the real SWRO brine, immersed in an HCl (1 M) solution of water (30 vol%) and methanol (70 vol%) for 24 hr for desorption of metal ions, rinsed with ethanol, and then sonicated in an aqueous ammonia (28%) solution for 30 min for neutralization prior to the next circle. For P(MPO-C5K(Et)), it was observed that 0.84 wt% of Li+adsorption and 0.090 wt% of Li+desorption in the first cycle (FIG. 28, entry la) and 2.94 wt% of Li+adsorption and 0.10 wt% of Li+desorption in the second cycle (FIG. 28, entry 2a). Over the two cycles, the adsorption of Na+and Mg2+were constantly as low as <0.0001 in each cycle (FIG. 28). After the two cycles, P(MPO-C5K(Et)) accumulated 3.78 wt% of Li+in total (cumulative Li+uptake) with keeping high Li+ / Na+and Li+ / Mg2+selectivity and released 0.19 wt% of Li+in total (cumulative Li+release). For desorption, the total recovery of Li+over the two cycles was 5.0 % of all adsorbed Li+(= [cumulative 0.19 wt% of desorbed Li+] / [cumulative 3.78 wt% of adsorbed Li+]). For P(MPO-C5K(CHO)), it was observed that 1.44 wt% of Li+adsorption and 0.91 wt% of Li+desorption in the first cycle (FIG. 29, entry la) and 1.80 wt% of Li+adsorption and 0.50 wt% of Li+desorption in the second cycle (FIG. 28, entry 2a). Over the two cycles, the adsorption of Na+and Mg2+were constantly as low as <0.0001 in each cycle (FIG. 29). After the two cycles, P(MPO-C5K(CHO)) accumulated 3.24 wt% of Li+in total (cumulative Li+uptake) with keeping high Li+ / Na+and Li+ / Mg2+selectivity and released 1.41 wt% of Li+in total (cumulative Li+release). For desorption, the total recovery of Li+over the two cycles was 43.5 % of all adsorbedLi+(= [cumulative 1.41 wt% of desorbed Li+] / [cumulative 3.24 wt% of adsorbed Li+]), showing high recovery.

[0208] Example 4: Commercial Applications

[0209] The COFs adsorbents of the present can be highly useful for Li+recovery from SWRO brine. Seawater contains -2600 billion tons of Li, which is about 15,000 times the amount on land. Mining this high-value Li can bring huge economic benefits. A massive amount of SWRO is readily available in Singapore. Li+capture by adsorption is a compelling technology and may lead to its commercialization.

[0210] Lithium-ion batteries are widely used, and the market is rapidly growing for electric vehicles and other applications. Thus, accessibility to huge amounts of critical metals such as cobalt, nickel and manganese is a global issue. The alternative organic cathodes (COFs in the present disclosure) may be a promising solution and may lead to its commercialization.

[0211] While the present disclosure has been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims. The scope of the present disclosure is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced.

Claims

CLAIMS1. A covalent organic framework comprising:polymer chains configured to form a covalently crosslinked polymer network, wherein each of the polymer chains comprises monomeric units each comprising a pyrrole-based moiety,wherein the pyrrole-based moiety is absent of any metal and comprises:a porphyrin moiety having an optionally substituted meso carbon, ora pyrrole moiety having an optionally substituted methylene group, ora mixture thereof;anda linker comprising two halogens, wherein the linker, if present, renders a non- covalent halogen bond which couples one nitrogen bond of one pyrrole-based moiety and one halogen of the linker and another non-covalent halogen bond which couples one nitrogen of another pyrrole-based moiety and the other halogen of the linker, andthe linker, when removed or if absent, renders a void which defines a pore in the covalently crosslinked polymer network.

2. The covalent organic framework of claim 1, wherein the porphyrin moiety is derived from a compound represented by formula (I):R’ R R'"(I)wherein R and / or R’ contains a polymerizable functional group; and / orwherein R, R’, R”, and R’”, are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide; orwherein R and R’ form a ring structure having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide, andR” and R’”, are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide.

3. The covalent organic framework of claim 1 or 2, wherein the porphyrin moiety is derived from a compound represented by formula (la):R1(la)wherein R1, R2, R3, R4, and / or R, contains a polymerizable functional group; and / orwherein R1is (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, aphosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, andwherein R2is a bond or a methylene group or wherein R2is (i) alkylene, alkenylene, alkynylene, oxyalkylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted, or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group,andwherein R3, R4, and R are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group;orwherein R1and R3form a ring structure containing a (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen -containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, andwherein R2is a bond or a methylene group or wherein R2is (i) alkylene, alkenylene, alkynylene, oxyalkylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted, or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group, andwherein R4and R5are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containingaliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen -containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group.

4. The covalent organic framework of any one of claims 1 to 3, wherein the porphyrin moiety is derived from one of the following compounds:H5. The covalent organic framework of any one of claims 1 to 4, wherein the pyrrole-based moiety comprises the porphyrin moiety and each of the monomeric 5 units is defined by one of the following:, orwherein n is a positive integer.

6. The covalent organic framework of any one of claims 1 to 5, wherein the pyrrole moiety is represented by formula (11):(II)wherein R” ” and / or R” ” ’ contains a polymerizable functional group; and / or wherein R””, R’””, R”””, and / or R”’”” are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide; orwherein R”” and R”’” form a ring structure having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, anether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide, and R”””, and / or R’””” are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide.

7. The covalent organic framework of any one of claims 1 to 6, wherein the pyrrole-based moiety comprises the pyrrole moiety and each of the monomeric units is represented by formula (Ila):R6wherein n is a positive integer; andwherein R6, R7, R8, R9, and / or R10contains a polymerizable functional group; and / orwherein R6(i) is hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, aphosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, andwherein R7is a bond or a methylene group or wherein R7is (i) alkylene, alkenylene, alkynylene, oxyalkylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted, or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group,andwherein R8, R9, and R10are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group;orwherein R6and R8form a ring structure containing a (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, andwherein R7may be a bond or a methylene group or wherein R7is (i) alkylene, alkenylene, alkynylene, oxyalkylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted, or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group, andwherein R9and R10are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen -containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group.

8. The covalent organic framework of any one of claims 1 to 7, wherein the pyrrole-based moiety comprises the pyrrole moiety and each of the monomeric units is defined by one of the following:wherein n is a positive integer.

9. The covalent organic framework of any one of claims 1 to 8, wherein the linker comprises 1,4-diiodotetrafluorobenzene, 1,2-diiodotetrafluorobenzene, 1,3-diiodotetrafluorobenzene, 1,3,5-triiodotrifluorobenzene, 1,2,4-triiodotrifluorobenzene, 1,2,3-triiodotrifluorobenzene, 1,2,4,5-tetraiododifluorobenzene, 1,2-diiodobenzene, 1.3-diiodobenzene, 1,4-diiodobenzene, 1,3,5-triiodobenzene, 1,2,4-triiodobenzene, 1.2.3-triiodobenzene, 1,2,4,5-tetraiodobenzene, hexaiodobenzene, 1,2-diiodoethane, 1.3-diiodopropane, 1,4-diiodobutane, 1,5-diiodoheptane, 1,6-diiodohexane, or an α,ω-diiodoalkane.

10. A method for forming the covalent organic framework of any one of claims 1 to 9, the method comprising:providing a mixture comprising:a monomer or an oligomer, wherein the monomer or the oligomer comprises a pyrrole-based moiety, wherein the pyrrole-based moiety is absent of any metal and comprises:a porphyrin moiety having an optionally substituted meso carbon,ora pyrrole moiety having an optionally substituted methylene group;a linker comprising two halogens; anda photo-initiator;co-crystallizing the monomer or the oligomer, with the linker, to form a cocrystal comprising the linker coupled to the monomer or the oligomer via halogen bond;andsubjecting the co-crystal to solid phase polymerization to form a covalently crosslinked polymer network.

11. The method of claim 10, further comprising removing the linker to generate pores in the covalently crosslinked polymer network, wherein removing the linker comprises washing the co-crystal with an alcohol, after subjecting the co-crystal to solid phase polymerization.

12. The method of claim 10 or 11, wherein providing the mixture comprises dissolving the monomer or the oligomer, the linker, and the photo-initiator, in an organic solvent to form the mixture.

13. The method of claim 12, wherein co-crystallizing the monomer or the oligomer, with the linker, comprises removing the organic solvent from the mixture.

14. The method of any one of claims 10 to 13, wherein providing the mixture comprises forming the monomer or the oligomer, wherein forming the monomer or the oligomer comprises:mixing a pyrrole with a carbonyl compound in the presence of a catalyst in a solvent to form the monomer and / or the oligomer.

15. The method of claim 14, wherein the carbonyl compound comprises a ketone, an aldehyde, a carboxylic acid, an ester, or a mixture thereof.

16. The method of claim 14 or 15, wherein the catalyst comprises methanesulfonic acid or trifluoroacetic acid.

17. The method of any one of claims 10 to 16, wherein the monomer comprises the porphyrin moiety, wherein the porphyrin moiety is a compound represented by formula (I):R’ R R'"(I)wherein R and / or R’ contains a polymerizable functional group; and / or wherein R, R’, R”, and R’”, are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide; orwherein R and R’ form a ring structure having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatomselected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus- containing group, a zwitterionic group or an ionic group, silicon or a silicon- containing group, a sulfur-containing group, or an alkylhalide, andR” and R’”, are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde- containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide.

18. The method of any one of claims 10 to 16, wherein the monomer comprises the porphyrin moiety, wherein the porphyrin moiety is a compound represented by formula (Ia):wherein R1, R2, R3, R4, and / or R5, contains a polymerizable functional group; and / orwherein R1is (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which areoptionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, andwherein R2is a bond or a methylene group or wherein R2is (i) alkylene, alkenylene, alkynylene, oxyalkylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted, or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group,andwherein R3, R4, and R5are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group;orwherein R1and R3form a ring structure containing a (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic oraromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, andwherein R2is a bond or a methylene group or wherein R2is (i) alkylene, alkenylene, alkynylene, oxyalkylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted, or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group, andwherein R4and R5are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group.

19. The method of any one of claims 10 to 18, wherein the monomer comprising the porphyrin moiety comprises:

20. The method of any one of claims 10 to 19, wherein the oligomer comprises the pyrrole moiety, wherein the pyrrole moiety is represented by formula (II):(II)wherein R”” and / or R”’” contains a polymerizable functional group; and / or wherein R””, R’””, R”””, and / or R’””” are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionallysubstituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide; orwherein R”” and R”’” form a ring structure having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide, and R”””, and / or R’””” are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, having one or more carbon atoms optionally substituted with a halogen, a hydroxyl-containing group, a heteroatom selected from O, N, or S, an amine, an amide, an ammonium group, a carboxylic acid or a carbonate group, boron or a boron-containing group, an ester, an ether, an epoxide, a ketone, an aldehyde-containing group, phosphorus or a phosphorus-containing group, a zwitterionic group or an ionic group, silicon or a silicon-containing group, a sulfur-containing group, or an alkylhalide.

21. The method of any one of claims 10 to 20, wherein the oligomer comprises the pyrrole moiety, wherein the pyrrole moiety is represented by formula (Ila):R6(IIa)wherein n is a positive integer; andwherein R6, R7, R8, R9, and / or R10contains a polymerizable functional group; and / orwherein R6is (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, andwherein R7is a bond or a methylene group or wherein R7is (i) alkylene, alkenylene, alkynylene, alkoxylene, cycloalkylene, cyclo alkenylene, or a divalent aromatic group, which are optionally substituted or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group,andwherein R8, R9, and R10are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group;orwherein R6and R8form a ring structure containing a hydrogen, hydroxyl, aldehyde, alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, an aromatic group, a halogen-containing aliphatic or aromatic group, a hydroxyl -containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group, andwherein R7is a bond or a methylene group or wherein R7is (i) alkylene, alkenylene, alkynylene, alkoxylene, cycloalkylene, cycloalkenylene, or a divalent aromatic group, which are optionally substituted or (ii) a halogen-containing divalent aliphatic or aromatic group, a hydroxyl-containing divalent aliphatic or aromatic group, an aldehyde-containing divalent aliphatic or aromatic group, an oxygen-containing divalent aliphatic or aromatic group, a sulfur-containing divalent aliphatic or aromatic group, a nitrogen-containing divalent aliphatic or aromatic group, a phosphorus-containing divalent aliphatic or aromatic group, a silicon-containing divalent aliphatic or aromatic group, or a boron-containing divalent aliphatic or aromatic group, andwherein R9and R10are each independently (i) hydrogen, hydroxyl, aldehyde, or halogen, or (ii) alkyl, alkenyl, alkynyl, alkoxyl, cycloalkyl, cycloalkenyl, or an aromatic group, which are optionally substituted, or (iii) a halogen-containing aliphatic or aromatic group, a hydroxyl-containing aliphatic or aromatic group, an aldehyde-containing aliphatic or aromatic group, an oxygen-containing aliphatic or aromatic group, a sulfur-containing aliphatic or aromatic group, a nitrogen-containing aliphatic or aromatic group, a phosphorus-containing aliphatic or aromatic group, a silicon-containing aliphatic or aromatic group, or a boron-containing aliphatic or aromatic group.

22. The method of any one of claims 10 to 21, wherein the oligomer comprising the pyrrole moiety comprises:

23. The method of any one of claims 10 to 22, wherein subjecting the co-crystal to solid phase polymerization comprises:exposing the co-crystal to ultraviolet light in an inert environment.

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