Metal organic framework

Abstract

A porous metal organic framework (MOF) comprising metal ions coordinated to linkers wherein one or more of the linkers have the general formula wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or fused polycyclic system; wherein when A is a 6-membered ring, the side chain of carboxylate is positioned at 2 and 5 positions; and n1 and n2 are independently integers selected from the range of 0 to 20. Preferably, the MOF comprises two kinds of chemically different linkers. # imgabs0 #

Description

Technical Field

[0001] The present invention generally relates to water absorption driven applications. More specifically, the present invention relates to metal organic frameworks for water absorption driven applications. Background Art

[0002] Providing fresh water to a rapidly growing world population is a global challenge, with more than half the world's regions projected to face water scarcity by 2050. Only 2.5% of all water on Earth is freshwater, with only a small fraction available directly from rivers and lakes (0.4%). The majority is locked up in glaciers (68.7%) or stored in groundwater (30.1%). With two-thirds of the world's population facing water stress, these freshwater resources are unlikely to address global water challenges in an energy-efficient manner.

[0003] Atmospheric water is a recoverable natural resource with the potential to provide water to arid regions of the world. However, the concentration of water in the air is very low, so finding a way to capture this water is a challenge.

[0004] Current technologies for producing water from humid air and fog include collecting fog through large networks, cooling the air below its dew point (the temperature at which air becomes saturated with water), and capturing the water with the aid of adsorbents.

[0005] However, fog collectors require permanently high relative humidity (RH≈100%) levels and a light breeze to promote condensation on the fine mesh, which severely limits the geographical areas suitable for fog collector applications. In addition, while condensation has wider geographical applicability, its energy efficiency and water productivity depend heavily on the local climate. In order to initiate condensation, the humid air needs to be cooled below the dew point by removing the associated sensible heat (the energy transfer required to cool the air). On the other hand, the concept of adsorption-based devices has a high potential for collecting water, even from dry air, but this depends largely on the performance of the adsorbent. Traditional desiccants used in such devices (such as CaCl2, silica gel or zeolites) have high water absorption capacity, but their strong affinity for water requires regeneration, which leads to energy-intensive operation and thus a low operating capacity of autonomous devices, especially when powered by low-grade energy.

[0006] Therefore, a first, non-exclusive object of the present invention is to efficiently collect water from air.

[0007] It has been previously proposed that metal-organic frameworks (MOFs) could be used to harvest water. Therefore, it would be beneficial to develop MOFs with better adsorption properties and / or that can more efficiently harvest and supply water. Summary of the Invention

[0008] It is an object of the present invention to provide a MOF that exhibits improved adsorption and / or has faster (or lower energy) desorption and / or can operate over many adsorption / desorption cycles without degradation.

[0009] Thus, a first aspect of the present invention provides a porous metal organic framework comprising metal ions coordinated to linkers, wherein one or more of the linkers has the general formula:

[0010]

[0011] wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system;

[0012] wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and

[0013] n1 and n2 are independently integers selected from the range 0 to 20.

[0014] In one embodiment, the metal organic framework may include a mixture of different ions and / or linkers. For example, the metal organic framework may include one or more first linkers of the formula:

[0015]

[0016] wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system;

[0017] wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and

[0018] n1 and n2 are independently integers selected from the range of 0 to 20; and one or more second linkers, the first linker and the second linker having different structures.

[0019] For example, the metal organic framework may include one or more second linkers of the formula:

[0020]

[0021] wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system;

[0022] wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and

[0023] n1 and n2 are independently integers selected from the range 0 to 20;

[0024] wherein the one or more first linkers and the one or more second linkers have different structures.

[0025] In this specification, "different structures" refers to chemically distinct structures. Thus, it encompasses situations where the linkers include or consist of different chemical entities, for example, one linker may have a 5-membered ring while the other has a 6-membered ring; and / or one linker may include a single heteroatom, such as N, while the other includes a different heteroatom, such as S or O; or the first and second linkers may be isomers of each other. For example, the first linker may include a pyrazine moiety and the second linker may include a pyrimidine moiety.

[0026] A second aspect of the present invention provides a porous metal-organic framework, wherein the metal-organic framework comprises one or more first linkers of the following formula:

[0027]

[0028] wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system;

[0029] wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and

[0030] n1 and n2 are independently integers selected from the range 0 to 20;

[0031] and a second linker, wherein the first linker has a different structure from the second linker.

[0032] The second linker may have the formula:

[0033]

[0034] wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system;

[0035] wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and

[0036] n1 and n2 are independently integers selected from the range 0 to 20;

[0037] wherein the one or more first linkers and the one or more second linkers have different structures.

[0038] The possibility to use different (chemical) linkers in MOFs offers a large number of possible options for tailoring the properties of MOFs to specific tasks or environments.

[0039] Specifically, the use of different ligands may provide MOFs with different and / or extended moisture range functionality and / or may facilitate more energy-efficient water harvesting procedures (e.g., as evidenced by lowered regeneration temperatures).

[0040] A may be selected from two 5-membered fused rings or two 6-membered fused rings, or a 5-membered and a 6-membered fused ring.

[0041] The metal ion can be coordinated with one or more linkers to form a cluster, such as a metal carboxylate cluster.

[0042] The metal ions may be selected from zirconium, nickel, iron, copper, manganese, aluminum, magnesium, calcium, strontium, barium, titanium, zinc, indium, cadmium, hafnium, lead, cobalt and / or chromium.

[0043] Alternatively, the metal ion may be a metal compound or a metal-containing complex.

[0044] In one embodiment, all linkers may comprise the same overall structure.

[0045] The heteroaryl or heterocycloalkyl ring A may include multiple heteroatoms. The heteroatoms may be selected from nitrogen, sulfur and oxygen.

[0046] Where multiple heteroatoms are present, they may all be the same. Alternatively, one or more of the heteroatoms may be different from the other heteroatoms.

[0047] The heteroaryl or heterocycloalkyl ring A may be fully saturated. The heteroaryl or heterocycloalkyl ring A may be unsaturated. The heteroaryl or heterocycloalkyl ring A may include at least one double bond. The heteroaryl or heterocycloalkyl ring A may include 1, 2, 3, 4, or 5 double bonds.

[0048] One or more of the linkers may have the following structure:

[0049]

[0050] wherein at least one of Z1, Z2, Z3, Z4, Z5 and Z6 is a heteroatom;

[0051] Z1, Z2, Z3, Z4, Z5 and Z6 are selected from N, NH, O, S, C(R1) or C(R1)(R2); wherein R1 and R2 are selected from H or alkyl, such as lower alkyl; and

[0052] n1 and n2 are independently integers selected from the range 0 to 20.

[0053] In the porous metal organic framework according to the present invention, n1 and n2 can be independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20. In one embodiment, n1 and n2 can be the same. Alternatively, n1 and n2 can be different.

[0054] In an embodiment of the present invention, one or more of the linkers comprises a 6-membered ring with the carboxylate side chains at positions 2, 5. We believe that such positions ensure larger pore sizes in the MOF, thereby improving water absorption.

[0055] The one or more linkers may have one of the following overall structures:

[0056] wherein X1, X2, X3 and X4 are selected from N, NH, S or O;

[0057] Y1, Y2, Y3 and Y4 are selected from C(R1)(R2) or C(R1);

[0058] wherein R1 and R2 are selected from H or alkyl, such as lower alkyl; and n1 and n2 are independently integers selected from the range of 0 to 20.

[0059] For example, one or more of the linkers may have the following structure:

[0060]

[0061] In an embodiment of the invention, one or more of the linkers comprises two 6-membered fused rings.

[0062] The one or more linkers may have one of the following overall structures:

[0063]

[0064] wherein X1, X2, X3, X4, X5 and X6 are selected from N, NH, O and S;

[0065] Y1, Y2, Y3, Y4, Y5 and Y6 are selected from C(R1)(R2) or C(R1);

[0066] wherein R1 and R2 are selected from H or alkyl, such as lower alkyl; and

[0067] n1 and n2 are independently integers selected from the range 0 to 20.

[0068] In an embodiment of the invention, one or more of the linkers comprises two 5-membered fused rings.

[0069] The one or more linkers may have one of the following overall structures:

[0070]

[0071] wherein X1, X2, X3 and X4 are selected from N, NH, O and S;

[0072] Y1, Y2, Y3 and Y4 are selected from C(R1)(R2) or C(R1);

[0073] wherein R1 and R2 are selected from H or alkyl; and

[0074] n1 and n2 are independently integers selected from the range 0 to 20.

[0075] The one or more linkers may have one of the following overall structures:

[0076]

[0077] wherein X1 and X4 are selected from NH, O and S;

[0078] X2 and X3 are selected from NH, N, O and S; and n1 and n2 are independently integers selected from the range of 0 to 20.

[0079] The one or more linkers may have one of the following overall structures:

[0080] wherein X1, X2 and X3 are selected from N, NH, O and S;

[0081] X4 is selected from NH, O and S; and n1 and n2 are independently integers selected from the range of 0 to 20.

[0082] For example, one or more of the linkers may have the following structure:

[0083] One or more of the linkers may include a 5-membered or 6-membered fused ring. The one or more linkers may have one of the following overall structures:

[0084]

[0085]

[0086] wherein X1 is selected from NH, O or S;

[0087] X2, X3, X4 and X5 are selected from NH, N, O and S; Y1 is C(R1)(R2);

[0088] Y2, Y3, Y4, Y5 and Y6 are selected from C(R1)(R2) or C(R1);

[0089] wherein R1 and R2 are selected from H or alkyl, such as lower alkyl; and

[0090] n1 and n2 are independently integers selected from the range 0 to 20.

[0091] The porous metal-organic framework may have permanent porosity.

[0092] Adsorbates such as water, fuels or gases (eg, SOx, NOx, hydrocarbons, flue gas, methane, hydrogen) may be able to be accommodated in the pores of the porous metal-organic framework.

[0093] The porous metal organic framework may have a pore volume greater than 0.20 cm 3 g -1 , for example, greater than 0.25, 0.30, 0.35, 0.40, 0.45, 0.50 or 0.55 cm 3 g -1 , for example, the porous metal organic framework has a range of 0.20 to 2.00 cm 3 g -1 The pore volume within, for example, 0.20 to 1.50 or 0.25 to 1.00 or 0.30 to 0.70, 0.40 to 0.60 or 0.50 to 0.65 cm 3 g -1 .

[0094] The porous metal organic framework may include a Brunauer-Emmett-Teller (BET) surface area in the range of 500 to 6000 m 2 g -1 , for example, 500 to 5500, 500 to 5000, 500 to 4500, 500 to 4000, 500 to 3500, 500 to 3000, 500 to 2500, 500 to 2000, 500 to 1500, 800 to 1500 or 900 to 1400 m 2 g -1 .

[0095] The porous metal-organic framework can have a gravimetric water uptake of greater than 20 wt %, such as greater than 25 wt %, 30 wt %, 35 wt %, 40 wt %, 45 wt %, 50 wt %, 55 wt %, 60 wt %, 65 wt % or 70 wt %, such as in the range of 20 to 80 wt %, such as 20 to 70 wt %, 30 to 65 wt %, 40 to 60 wt % or 45 to 60 wt %, at a relative humidity of 90% and an adsorption temperature of 25°C.

[0096] The volumetric water absorption of the metal organic framework at 20% relative humidity can be greater than 0.30 g 水 / cm 3 , for example, greater than 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85 or 0.90 g水 / cm 3 .

[0097] The bulk density of the porous metal-organic framework can be in the range of 0.80 to 1.20 g / cm 3 Within, for example 0.90 to 1.10g 水 / cm 3 , for example, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1.00, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09 or 1.10 g / cm 3 .

[0098] The porous metal organic framework can be fully regenerated at a temperature in the range of 25°C to 90°C, for example, at 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 70°C, 85°C or 90°C.

[0099] Advantageously, the porous metal-organic frameworks according to the present invention provide a variety of structures, allowing for the necessary chemical and geometric optimization required to achieve the desired water absorption properties.

[0100] Furthermore, the porous metal-organic framework according to the present invention has high chemical stability toward water, customizable hydrophilicity and hydrophobicity, adjustable pore size, and can fine-tune the adsorption profile and regulate the adsorption kinetics.

[0101] According to yet another aspect of the present invention, there is provided a cluster for a metal organic framework, the cluster comprising a metal ion coordinated to one or more linkers, wherein one or more of the linkers has the following general formula:

[0102]

[0103] wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system;

[0104] wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and

[0105] n1 and n2 are independently integers selected from the range 0 to 20.

[0106] According to another aspect of the present invention, there is provided a cluster for a metal organic framework, the cluster comprising a metal ion coordinated to one or more linkers, wherein the one or more linkers comprise at least one first linker of the formula:

[0107]

[0108] wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system;

[0109] wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and

[0110] n1 and n2 are independently integers selected from the range 0 to 20;

[0111] and at least one second linker, wherein the first linker has a different structure than the second linker.

[0112] For example, the at least one second linker may have the formula:

[0113]

[0114] wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system;

[0115] wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and

[0116] n1 and n2 are independently integers selected from the range 0 to 20

[0117] A may be selected from two 5-membered fused rings or two 6-membered fused rings, or a 5-membered and a 6-membered fused ring.

[0118] The clusters of these embodiments are metal carboxylate clusters.These clusters are linked together by ligands to form a crystalline porous framework.

[0119] According to another aspect of the present invention, there is provided a method for synthesizing a porous metal-organic framework, the method comprising:

[0120] a) dissolving metal ions and linkers in water, wherein one or more of the linkers has the following general formula:

[0121]

[0122] wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system;

[0123] wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and

[0124] n1 and n2 are independently integers selected from the range 0 to 20; and

[0125] b) adding a Bronsted-Lowry base, such as NaOH, LiOH, triethylamine, to the mixture; and

[0126] c) heating the mixture to produce a crystalline material.

[0127] In one embodiment, the linker dissolved in water may include linkers having different structures.

[0128] A may be selected from two 5-membered fused rings or two 6-membered fused rings, or a 5-membered and a 6-membered fused ring.

[0129] The metal ions may be selected from zirconium, nickel, iron, copper, manganese, aluminum, magnesium, calcium, strontium, barium, titanium, zinc, indium, cadmium, hafnium, lead, cobalt and / or chromium.

[0130] Alternatively, the metal ion may be a metal compound or a metal-containing complex.

[0131] One or more of the linkers may be a linker as described herein.

[0132] Step (c) may comprise heating the mixture to a temperature in the range of 30°C to 100°C, for example 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C.

[0133] Step (c) may comprise heating the mixture for 4 to 72 hours, for example 24 hours.

[0134] The method may further comprise activating the porous metal-organic framework, comprising:

[0135] (i) soaking the crystalline material in deionized water;

[0136] (ii) soaking the crystalline material in methanol; and

[0137] (iii) heating the crystalline material.

[0138] Step (i) and / or step (ii) may comprise soaking the crystalline material for a period of 4 minutes to 24 hours.

[0139] Step (iii) may comprise heating the crystalline material to 40 to 100°C for 1 minute to 2 hours, then heating to 40 to 150°C for 10 minutes to 2 hours, then heating to 60°C for 10 minutes to 2 hours.

[0140] Although we have disclosed that the MOFs of the present invention can include linkers or ligands with different structures, the methods of the present invention use the same metal center and provide a convenient "green" method for making MOFs using water as the main solvent. Different linkers can be used to provide MOFs with tunable properties, thereby facilitating the use of MOFs in different environments (i.e., different humidity, temperature, etc.).

[0141] The following explanations of terms and methods are provided to better describe the compounds and methods of the present invention and to guide those skilled in the art to practice the present disclosure. It should also be understood that the terms used in this disclosure are for the purpose of describing specific embodiments and examples only and are not intended to be limiting.

[0142] The term "alkyl" refers to a branched or unbranched saturated hydrocarbon group of 1 to 24 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, decyl, tetradecyl, hexadecyl, eicosyl, tetracosyl, etc. "Lower alkyl" is a branched or unbranched saturated hydrocarbon having 1 to 10 carbon atoms. Alkyl can be a "substituted alkyl" in which one or more hydrogen atoms are replaced by a substituent such as a halogen, cycloalkyl, alkoxy, amino, hydroxyl, aryl, or carboxyl group.

[0143] The term "cycloalkyl" refers to a non-aromatic carbonyl ring consisting of at least three carbon atoms. Examples of cycloalkyls include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like. The term "heterocycloalkyl" is a cycloalkyl as defined above in which at least one of the carbon atoms of the ring is substituted with a heteroatom such as, but not limited to, nitrogen, oxygen, sulfur, or phosphorus.

[0144] The term "aryl" refers to any group derived from an aromatic group, including but not limited to a benzene ring or an optionally substituted benzene ring system fused to one or more optionally substituted benzene rings. "Heteroaryl" is defined as an aryl group containing at least one heteroatom within the aryl ring. Examples of heteroatoms include but are not limited to nitrogen, oxygen, and sulfur.

[0145] Clusters are chemical entities that connect two-position ligands to each other in a 3D structure.

[0146] It will be understood that each atom has the correct bond valences. For example, carbon forms 4 bonds, nitrogen forms 3 bonds, and oxygen and sulfur each form 2 bonds.

[0147] therefore, The bonds represented can be single or double bonds, so that each atom has the correct bond valence.

[0148] Within the scope of the present application, it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings and in particular their individual features may be adopted independently or in any combination. That is, all embodiments and / or features of any embodiment may be combined in any manner and / or combination unless such features are incompatible. For the avoidance of doubt, the terms "may", "and / or", "for example", "for example" and any similar terms used herein should be interpreted as non-restrictive, so that any feature described in this manner is not necessarily present. In fact, any combination of optional features is clearly envisioned without departing from the scope of the present invention, whether or not such features are clearly claimed. The applicant reserves the right to amend any originally filed claim or to submit any new claim accordingly, including the right to amend any originally filed claim to make it subordinate to any other claim and / or to merge any features of any other claim, even though it was not originally claimed in this way. BRIEF DESCRIPTION OF THE DRAWINGS

[0149] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0150] Figure 1 Pyrazine ligands used to synthesize MOFs according to the present invention are shown;

[0151] Figure 2 Indole ligands used to synthesize MOFs according to the present invention are shown;

[0152] Figure 3 Pyrimidine ligands used to synthesize MOFs according to the present invention are shown;

[0153] Figure 4 shows a scanning electron microscope image of a MOF according to the present invention;

[0154] Figure 5 is a graph showing nitrogen adsorption and desorption according to surface area measurements of MOFs of the present invention;

[0155] Figure 6 is a powder X-ray diffraction pattern of the MOF according to the present invention;

[0156] Figure 7 is a graph showing the gravimetric water uptake isotherm of the MOF according to the present invention;

[0157] Figure 8 is a graph showing the water adsorption kinetics of the MOF according to the present invention;

[0158] Figure 9 is a graph showing the MOF water desorption kinetics at different temperatures.

[0159] Figure 10 is a graph showing the cyclic stability of the MOF according to the present invention;

[0160] Figure 11 is a graph showing the cyclic stability of the MOF according to the present invention;

[0161] Figure 12 is a graph showing the volumetric water uptake by a MOF according to the present invention compared to known MOFs;

[0162] Figure 13A is a graph showing nitrogen adsorption and desorption according to gravimetric surface area measurements of MOFs according to the present invention;

[0163] Figure 13B is a graph showing nitrogen adsorption and desorption according to volume surface area measurements of MOFs of the present invention; and

[0164] Figure 14 is a graph showing the volumetric nitrogen uptake by a MOF according to the present invention compared to known MOFs;

[0165] Figure 15 is a graph showing the gravimetric water uptake isotherm of the MOF according to the present invention;

[0166] Figure 16 is a graph showing the gravimetric water uptake isotherm of the MOF according to the present invention;

[0167] Figure 17 is a graph showing the water adsorption kinetics of the MOF according to the present invention;

[0168] Figure 18 is a graph showing the water desorption kinetics of the MOF according to the present invention.

[0169] refer to Figure 1 , showing a pyrazine linker, 2,5-pyrazinedicarboxylic acid linker 1, used to form a MOF according to the present invention.

[0170] The 2,5-pyrazinedicarboxylic acid linkers 1 each coordinate with an aluminum ion to form alumina clusters, resulting in a MOF we call Nov-1.

[0171] refer to Figure 2 , showing an indole linker, 1H indole 2,5 dicarboxylic acid linker 2, used to form a MOF according to the present invention.

[0172] The 1H-indole-2,5-dicarboxylic acid linkers 2 are each coordinated to an aluminum ion to form alumina clusters, resulting in a MOF we call Nov-2.

[0173] refer to Figure 3, showing the connection with linker 1 ( Figure 1 ) in combination with the pyrimidine linker, 2,5-pyrimidinedicarboxylate linker 3, both of which coordinate with aluminum ions to form aluminum oxide clusters, resulting in a single MOF that we call Nov-3. DETAILED DESCRIPTION

[0174] Synthesis and activation of MOF

[0175] The synthesis process is carried out in the open air as follows:

[0176] Synthesis of Nov-1

[0177] Nov-1: 5.2 g of aluminum chloride hexahydrate (AlCl3·6H2O) and 3.62 g of 2,5-pyrazinedicarboxylic acid were dissolved in 375 ml of water in a 500 ml glass bottle. Subsequently, LiOH (1.5 g) was added to the above mixture. The glass bottle was then sealed and heated in an isothermal oven at 100°C for 4 to 20 hours to obtain a brown, round (50 μm × 50 μm × 20 μm) crystalline material, which was observed by scanning electron microscopy (SEM), see Figure 2 .

[0178] MOF activation: The newly synthesized crystalline material powder (e.g., unactivated Nov-1) is soaked in deionized water for 4 minutes to 1 day (approximately 24 hours), and then soaked in methanol for 4 minutes to 1 day (approximately 24 hours). The crystalline material (e.g., unactivated Nov-1) is then heated to 40 to 100°C for 4 minutes to 2 hours, then raised to 150°C for 4 minutes to 2 hours, and finally raised to 40 to 160°C for 4 minutes to 2 hours to produce an activated sample (e.g., activated Nov-1).

[0179] The apparent surface area of Nov-1 MOF was determined by nitrogen adsorption-desorption isotherms collected on a Micromeritics Tristar II 3020 at 77 K, where the temperature was kept constant using a liquid nitrogen bath.

[0180] Nov-1 MOF has permanent porosity, 1380m 2 g -1 Brunauer-Emmet-Taylor (BET) surface area and 0.55 cm 3 g -1 The pore volume (see Figure 3 ; nitrogen adsorption 30 and nitrogen desorption 31).

[0181] Synthesis of Nov-2

[0182] Nov-2: 0.8 g of lithium chloride and 2.1 g of 1H-indole-2,5-dicarboxylic acid were dissolved in 300 ml of water. Subsequently, 4.6 g of aluminum chloride hexahydrate (AlCl₃·6H₂O) was added to the mixture, resulting in the formation of a white precipitate. The reaction mixture was then heated at 120°C for 21 hours. The resulting crystals were then washed three times with distilled water and methanol, and then dried at 140°C for 12 hours.

[0183] Synthesis of Nov-3

[0184] Nov-3: 1.6g of lithium hydroxide and 2g of pyrimidine-2,5-dicarboxylic acid were dissolved in 750ml of water. 5.5g of pyrazine-1,5-dicarboxylic acid was then added to the reaction mixture, which was then sonicated for 3 minutes. 10.4g of aluminum chloride hexahydrate (AlCl3·6H2O) was added to the mixture, and the mixture was heated at 120°C for 21 hours. The resulting crystals were then washed three times with distilled water and methanol, and then dried at 140°C for 12 hours.

[0185] The MOFs were synthesized using water as a solvent, without the need for centrifugation, densification, applied pressure, or binders.

[0186] The use of different ligands (even mixtures of ligands) shows that the method can be used to produce MOFs with different properties.

[0187] In alternative embodiments, the MOF synthesis may include aluminum sulfate, such as aluminum sulfate octahydrate, aluminum acetylacetonate, or aluminum acetate, as the aluminum source. Of course, different salts of different metals may also be used.

[0188] Such as water, fuel or gas (such as SO x 、NO x Adsorbates such as carbon dioxide, hydrocarbons, methane, hydrogen, and flue gas can be accommodated in the pores of MOFs.

[0189] Experimental methods

[0190] refer to Figure 4 , shows the powder X-ray diffraction (PXRD) pattern of Nov-1 MOF. Nov-1 exhibits a crystalline robust structure, as indicated by the sharp peaks in PXRD.

[0191] Powder X-ray diffraction (PXRD) data were collected at room temperature using a D8 Bruker X-ray powder diffractometer (CuKα1 radiation, The line-focus Cu X-ray tube was operated at 40 kV and 40 mA. Intensity data from 5 to 50 degrees 2θ were collected over a 30-minute period.

[0192] The water absorption properties of the MOFs were measured using a custom-built dynamic vapor sorption gravimetric analyzer, with 15 to 20 grams placed in a sample pan controlled by a mass scale. The samples were evacuated for 6 hours before the measurements began. Measurements were performed at temperatures of 25°C, 30°C, and 45°C within a relative pressure range of 0 to 0.9. The desorption temperature was varied between 90°C and 27°C.

[0193] In order to more fully understand the present invention, reference is made to the following non-limiting examples:

[0194] Example 1:

[0195] According to a first example of the present invention, a graph showing the gravimetric water uptake of Nov-1 at a relative humidity (RH) of up to 90% and an adsorption temperature of 25°C is shown (see Figure 7 The data show that Nov-1 has a sharp increase in water uptake, from approximately 11 wt% at 10% RH to approximately 51.2 wt% at 20% RH. Water uptake further increases with increasing RH, reaching a maximum of 60 wt% at 90% RH.

[0196] Example 2:

[0197] According to a second example of the present invention, a graph showing the adsorption kinetics of Nov-1 at different RHs at a constant adsorption temperature of 25°C is shown (see Figure 8 At 60% RH (line 60), Nov-1 reached full saturation within 25 minutes, with a water uptake of 54 wt%. At 40% RH (line 61) and 30% RH (line 62), Nov-1 achieved similar water uptake capacities of approximately 52 wt% in 50 and 75 minutes, respectively. At 20% RH (line 63), Nov-1 reached a water uptake capacity of 48 wt% in 150 minutes.

[0198] Example 3:

[0199] According to a third example of the present invention, a graph showing the desorption kinetics of Nov-1 at different temperatures in dry conditions is shown (see Figure 9 ). At 90°C (line 70), Nov-1 reaches complete desorption after about 20 minutes. At a desorption temperature of 65°C (line 71), Nov-1 requires about 30 minutes to reach complete desorption. At 55°C (line 72), Nov-1 reaches complete desorption after about 42 minutes. At 45°C (line 73), Nov-1 reaches complete desorption after about 50 minutes. At a desorption temperature of 27°C (line 74), Nov-1 requires about 80 minutes to reach complete desorption.

[0200] Example 4:

[0201] According to the fourth example of the present invention, the cycling stability of Nov-1 at 90% RH and 25°C adsorption temperature is shown (see Figure 10 ). Nov-1 MOF was exposed to air (about 28 minutes) until it became completely saturated with water vapor. Nov-1 MOF was then heated at 90°C (about 20 minutes) to completely desorb the captured water. Nov-1 MOF was fully regenerated with no performance degradation after 24 cycles (see Figure 10 ).

[0202] Example 5:

[0203] Dynamic cycling performance tests showed that Nov-1 MOF did not degrade in performance after up to 160 cycles under the following conditions: adsorption for 28 minutes in 90% RH and desorption for 20 minutes in a dry environment at 90°C, confirming the high capacity and stability of Nov-1 MOF (see Figure 11 ).

[0204] Comparative Example 1:

[0205] Comparative Example according to the present invention shows a comparison of the volumetric water uptake of Nov-1 (line 100) and MOF-303 (line 101) at 25°C at different RH values (see Figure 12 ). Data show that Nov-1 reaches 0.54g at 20% RH 水 / cm 3 The volume absorption capacity of MOF-303 is only 0.15g 水 / cm 3 The maximum volume absorption reached by Nov-1 (line 100) and MOF-303 (line 101) is 0.64 g, respectively. 水 / cm 3 and 0.16g 水 / cm 3 The high volumetric absorption of Nov-1 is due to its high bulk density. Nov-1 exhibits a very high density of 1.04 g / cm 3 , while the adsorption characteristics did not decrease, maintaining the same volumetric water uptake as that of powder and single crystal.

[0206] Example 6:

[0207] According to a further example of the present invention, the BET surface area measurement results of Nov-1 MOF are shown, showing the gravimetric absorption ( Figure 13A ; nitrogen adsorption 110 and nitrogen desorption 111) and volume absorption ( Figure 13B; nitrogen adsorption 112 and nitrogen desorption 113). Nov-1 exhibited a very high density without a decrease in gas absorption properties, maintaining the same volumetric gas absorption as powders and single crystals.

[0208] Comparative Example 2:

[0209] According to a comparative example of the present invention, the volumetric nitrogen uptake of Nov-1 MOF (line 120) and MOF-303 (line 121) is shown. Figure 14 Compared with MOF-303, Nov-1 has a greater nitrogen absorption capacity.

[0210] Comparative Example 3:

[0211] Compared to other known materials (such as MOF-303 and MOF-573), Nov-1 MOF has higher capacity at 10% to 90% RH and is an indispensable part of atmospheric water generation (AWG) and heat pump (HP) (also known as thermal battery) devices.

[0212] Comparative Example 4:

[0213] Compared to other known porous materials, such as MOF-303, Nov-1 MOF has a higher volumetric gas uptake capacity.

[0214] Example 7:

[0215] According to a seventh example of the present invention, a graph showing the gravimetric water absorption of Nov-2 at a RH of up to 100% and an adsorption temperature of 25° C. is shown (see Figure 15 The data showed that Nov-2's water absorption increased dramatically, from approximately 4 wt% at RH = 20% to approximately 30 wt% at RH = 30%. Water absorption further increased with increasing RH, reaching a maximum of approximately 37 wt% at RH = 100%.

[0216] The ligand used is 1H-indole-2,5-dicarboxylic acid (5-carboxyindole-2-carboxylic acid), which has a 5- to 6-membered fused ring structure, with the fifth ring being pyrrole and the sixth ring being benzene. The carboxyl groups are located at the 2- and 5-positions, resulting in an enlarged pore size and facilitating their binding to the aluminum metal cluster, thus forming a stable structure. The ligand consists of two components: a hydrophilic portion containing a nitrogen atom within the pyrrole ring and a hydrophobic segment provided by the benzene ring. This configuration achieves a moderate heat of adsorption and enhances desorption kinetics.

[0217] Example 8:

[0218] According to an eighth example of the present invention, a graph showing the gravimetric water absorption of Nov-3 at a RH of up to 90% and an adsorption temperature of 25° C. is shown (see Figure 16The data showed that Nov-3's water absorption increased dramatically, from approximately 10 wt% at RH = 10% to approximately 44 wt% at RH = 17%. Water absorption further increased with increasing RH, reaching a maximum of approximately 55 wt% at RH = 90%.

[0219] Example 9

[0220] According to a ninth example of the present invention, a graph showing the adsorption kinetics of Nov-3 at RH=90% at a constant adsorption temperature of 25°C is shown (see Figure 17 At RH = 90%, rapid adsorption kinetics were observed, with Nov-3 reaching full saturation in just 10 minutes with a water uptake of 55 wt%.

[0221] While we do not wish or intend to be bound by any particular theory, we believe that the use of different ligands contributes to the enhanced water absorption properties.

[0222] Example 10

[0223] According to a tenth example of the present invention, a graph showing the rapid desorption kinetics of Nov-3 at 90° C. in dry conditions is shown (see Figure 18 ). Rapid desorption kinetics were observed, with Nov-3 reaching complete desorption in only 15 min.

[0224] The simple synthetic procedures and high scalability of these MOFs make them suitable for a variety of applications, including:

[0225] Atmospheric water generation (AWG);

[0226] Gas storage and separation: hydrogen, methane, CO x 、NO x 、SO x , krypton, xenon, nitrogen, argon, oxygen, arsine;

[0227] Collecting water from the air;

[0228] Heat pumps (HP) or thermal batteries for cooling and desalination;

[0229] Heat pumps (HP) for ice formation using alcoholic substances;

[0230] Drug delivery

[0231] Membrane filtration in seawater desalination;

[0232] Nerve agent detoxification;

[0233] Proton conduction in fuel cells;

[0234] Energy storage;

[0235] catalytic CO2 conversion; and

[0236] Water treatment

[0237] It will be appreciated by those skilled in the art that any number of combinations of the foregoing features and / or features shown in the accompanying drawings provide significant advantages over the prior art and are therefore within the scope of the invention described herein.

Claims

1. A porous metal-organic framework comprising metal ions coordinated to linkers, wherein one or more of the linkers has the following general formula: wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system; wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and n1 and n2 are independently integers selected from the range 0 to 20.

2. The porous metal-organic framework according to claim 1, wherein the one or more linkers comprise: At least one first linker of the formula: wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system; wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and n1 and n2 are independently integers selected from the range 0 to 20; and at least one second linker, The first linker and the second linker have different structures.

3. The porous metal-organic framework according to claim 2, wherein the second linker has the following formula: wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system; wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and n1 and n2 are independently integers selected from the range 0 to 20.

4. A porous metal-organic framework according to any preceding claim, wherein For at least one of the one or more linkers, A is selected from two 5-membered fused rings, two 6-membered fused rings, or a 5-membered and a 6-membered fused ring.

5. The porous metal-organic framework according to any of the preceding claims, wherein the metal ions are selected from zirconium, nickel, iron, copper, manganese, aluminum, magnesium, calcium, strontium, barium, titanium, zinc, indium, cadmium, hafnium, lead, cobalt and / or chromium.

6. The porous metal-organic framework according to any preceding claim, wherein the heteroaryl or heterocycloalkyl ring A comprises a plurality of heteroatoms.

7. The porous metal-organic framework according to any one of the preceding claims, wherein the heteroatoms are selected from nitrogen, sulfur and oxygen.

8. The porous metal-organic framework according to any preceding claim, wherein the heteroaryl or heterocycloalkyl ring A comprises at least one double bond.

9. The porous metal-organic framework according to any one of the preceding claims, wherein one or more linkers have the following structure: wherein at least one of Z1, Z2, Z3, Z4, Z5 and Z6 is a heteroatom; Z1, Z2, Z3, Z4, Z5 and Z6 are selected from N, NH, O, S, C(R1) or C(R1)(R2); wherein R1 and R2 are selected from H or alkyl, such as lower alkyl; and n1 and n2 are independently integers selected from the range 0 to 20.

10. A porous metal organic framework according to any preceding claim, wherein n1 and n2 are the same.

11. The porous metal-organic framework according to any preceding claim, wherein one or more of the linkers has a structure selected from the group consisting of:

12. The porous metal-organic framework according to claim 11, comprising a first linker selected from one of (I), (II) or (III) and a second linker selected from one of (I), (II) or (III), wherein the first linker and the second linker have different chemical structures.

13. The porous metal-organic framework according to any one of the preceding claims, wherein the porous metal-organic framework has permanent porosity.

14. A porous metal organic framework according to any preceding claim, wherein adsorbates such as water, fuels or gases (e.g. SOx, NOx, hydrocarbons, flue gases, methane, hydrogen) can be accommodated in the pores of the porous metal organic framework.

15. The porous metal-organic framework according to any one of the preceding claims, wherein the porous metal-organic framework has a pore volume greater than 0.20 cm 3 g -1 , for example, greater than 0.25, 0.30, 0.35, 0.40, 0.45, 0.50 or 0.55 cm 3 g -1 , for example, the porous metal organic framework has a pore volume in the range of 0.20 to 2.00 cm 3 g -1 , for example 0.20 to 1.50 or 0.25 to 1.00 or 0.30 to 0.70, 0.40 to 0.60 or 0.50 to 0.65 cm 3 g -1 .

16. A porous metal organic framework according to any preceding claim comprising a Brunauer-Emmet-Teller (BET) surface area in the range of 500 to 6000 m 2 g - 1, for example, 500 to 5500, 500 to 5000, 500 to 4500, 500 to 4000, 500 to 3500, 500 to 3000, 500 to 2500, 500 to 2000, 500 to 1500, 800 to 1500 or 900 to 1400 m 2 g -1 .

17. A porous metal-organic framework according to any preceding claim, wherein the porous metal-organic framework has a gravimetric water uptake at a relative humidity of 90% and an adsorption temperature of 25°C of greater than 20 wt%, for example greater than 25 wt%, 30 wt%, 35 wt%, 40 wt%, 35 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt% or 70 wt%, for example in the range of 20 to 80 wt%, for example 20 to 70 wt%, 30 to 65 wt%, 40 to 60 wt% or 45 to 60 wt%.

18. The porous metal organic framework according to any one of the preceding claims, wherein the volumetric water uptake of the metal organic framework at 20% relative humidity is greater than 0.30 g 水 / cm 3 , for example, greater than 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85 or 0.90 g 水 / cm 3 .

19. The porous metal organic framework according to any one of the preceding claims, wherein the bulk density of the porous metal organic framework is in the range of 0.80 to 1.20 g / cm 3 , for example 0.90 to 1.10 g 水 / cm 3 , for example, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1.00, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09 or 1.10 g / cm 3 .

20. The porous metal-organic framework according to any preceding claim, wherein the porous metal-organic framework is fully regenerated at a temperature in the range of 25°C to 90°C, for example at 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 70°C, 85°C or 90°C.

21. A method for synthesizing a porous metal-organic framework, the method comprising: a) dissolving metal ions and linkers in water, wherein one or more of the linkers has the following general formula: wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system; wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and n1 and n2 are independently integers selected from the range 0 to 20; and b) adding a Bronsted-Lowry base, such as NaOH, LiOH, triethylamine, to the mixture; and c) heating the mixture to produce a crystalline material.

22. The method of claim 21, wherein step a) comprises dissolving a plurality of chemically distinct linkers in water.

23. The method according to claim 21 or 22, wherein step a) comprises dissolving a first linker having the following general formula in water: wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system; wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and n1 and n2 are independently integers selected from the range 0 to 20 and dissolving the linker or the second linker in water.

24. The method according to claim 22 or 23, wherein step a) comprises dissolving the second linker having the following general formula in water: wherein A is a heteroaryl or heterocycloalkyl ring or ring system selected from a 6-membered ring or a fused polycyclic ring system; wherein when A is a 6-membered ring, the carboxylate side chain is at the 2,5 position; and n1 and n2 are independently integers selected from the range 0 to 20.

25. The method of claim 22, 23 or 24, comprising dissolving the first linker and the second linker in water simultaneously or sequentially.

26. The method of any one of claims 21 to 25, wherein for at least one of the one or more linkers, A is selected from two 5-membered fused rings or two 6-membered fused rings, or a 5-membered and a 6-membered fused ring.

27. The method of claims 21 to 26, wherein step (c) comprises heating the mixture to a temperature in the range of 30°C to 100°C, for example 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C.

28. A method according to any one of claims 21 to 27, wherein step (c) comprises heating the mixture for 4 to 72 hours, such as 24 hours.

29. The method of any one of claims 21 to 28, further comprising activating the porous metal organic framework, the method comprising: (i) contacting the crystalline material with deionized water (e.g., soaking it in deionized water); (ii) contacting the crystalline material with methanol (e.g., immersing it in methanol); and (iii) heating the crystalline material.

30. The method of claim 29, wherein step (i) and / or step (ii) comprises soaking the crystalline material for a period of 4 minutes to 24 hours.

31. The method of claim 29 or 30, wherein step (iii) comprises heating the crystalline material to 40 to 100°C for 1 minute to 2 hours, then heating to 40 to 150°C for 10 minutes to 2 hours, then heating to 60°C for 10 minutes to 2 hours.

32. A porous metal-organic framework comprising a metal and one or more linkers, the porous metal-organic framework being formed by the method of any one of claims 21 to 31.

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