Metal-organic framework containing pyrazolyl carboxylate ligand and method for producing same

Abstract

Metal-organic frameworks (MOFs) are highly porous entities containing multidentate organic ligands coordinated to multiple metal centers. Ambient-condition stable MOFs can include multiple metal clusters containing one or more MO clusters (where M is a metal) and multiple 4-pyrazole carboxylate ligands coordinated to the multiple metal clusters to define an at least partially crystalline network with multiple internal pores. MOFs can have Pa3 symmetry, which can be converted to Fm3m symmetry upon activation. A method for synthesizing MOFs can include combining a metal source, such as a preformed metal cluster, with 4-pyrazole carboxylic acid and reacting the preformed metal cluster with 4-pyrazole carboxylic acid to form a MOF containing multiple metal clusters coordinated to multidentate organic ligands containing 4-pyrazole carboxylate, having an at least partially crystalline network with multiple internal pores defined therein.

Description

[Technical field]

[0001] Field The present invention relates to metal-organic framework materials (MOFs) formed from pyrazolylcarboxylate ligands. [Background technology]

[0002] background MOFs are a relatively new class of highly porous network materials. In contrast to zeolites, which are purely inorganic in nature, MOFs contain metal ions or clusters interconnected by polydentate organic ligands, which act as "pillars" that bridge the metal ions or clusters together into a wide range of one-, two-, or three-dimensional coordination networks (e.g., coordination polymers). MOFs offer a high degree of structural and functional tunability due to the ability to adjust and control the structure of the organic components, and to a lesser extent, the structure of the network topology, a feature not typically available with other conventional porous materials. MOFs are characterized by low density, high internal surface area, and pores and channels that are tunable by the choice of polydentate organic ligands and metal sources used during synthesis.

[0003] MOF-5, also known as IRMOF-1, with the general formula Zn4O(1,4-benzenedicarboxylate)3, is the prototypical example of a MOF and was developed nearly 20 years ago. This material and its isoreticular counterparts (i.e., materials with the same topology) exhibit high pore volume and high surface area and have been explored for use in applications that exploit these features. However, the long-term performance and stability of these MOFs under ambient moisture conditions has not been conclusively demonstrated. MOFs have been extensively explored for applications in gas storage, gas and liquid separation, sensing, catalysis, drug delivery, and waste remediation, among others. The wealth of potential applications for MOFs arises from the infinite combinations of polydentate organic ligands and metal sources available for the synthesis of MOFs. In particular, the expected ability to control the porosity, composition, and functionality of MOFs by the choice of components, functionalization, or post-synthetic modifications makes MOFs promising candidates for the provision of stable materials that are specifically designed for specific applications. One of the challenges in designing porous materials such as MOFs is the large number of possible coordination environments for any given metal ion. It is therefore desirable to prepare MOFs with known geometries for the various metal-containing nodes. Furthermore, it is desirable to provide MOFs via synthesis that is more reproducible and characterized by higher yields, while also allowing for more variable synthesis conditions, resulting in a variety of structural behaviors. Summary of the Invention

[0004] overview In some embodiments, the disclosure provides a MOF comprising a plurality of metal clusters comprising one or more MO clusters, where M is a metal, and a plurality of polydentate organic ligands coordinated to the plurality of metal clusters to define an at least partially crystalline network having a plurality of interior pores, the polydentate organic ligand comprising 4-pyrazole carboxylate, wherein the at least partially crystalline network has an X-ray powder diffraction pattern comprising characteristic diffraction peaks consistent with Pa3 symmetry. In some or other embodiments, the disclosure provides an MOF comprising a plurality of metal clusters comprising one or more MO (M is a metal) clusters and a plurality of multidentate organic ligands coordinated to the plurality of metal clusters to define an at least partially crystalline network having a plurality of interior pores, the multidentate organic ligand comprising 4-pyrazole carboxylate, wherein the at least partially crystalline network has an X-ray powder diffraction pattern comprising characteristic diffraction peaks at least 8.91, 9.96, 10.9, and 12.6 (all ±5%) degrees two theta (°2θ).

[0005] In some embodiments, a method of synthesizing a MOF may include combining a metal source with 4-pyrazole carboxylic acid; and reacting the metal source with the 4-pyrazole carboxylic acid to form a MOF having an at least partially crystalline network having a plurality of internal pores defined therein and comprising a plurality of metal clusters coordinated to a multidentate organic ligand comprising 4-pyrazole carboxylate, the plurality of metal clusters comprising one or more MO clusters, where M is a metal, and wherein the at least partially crystalline network has an X-ray powder diffraction pattern comprising characteristic diffraction peaks at least 8.91, 9.96, 10.9, and 12.6 (all ±5%) degrees two theta (°2θ). In some or other embodiments, the method of the present disclosure may include combining a preformed metal cluster with 4-pyrazole carboxylic acid; and reacting the preformed metal cluster with the 4-pyrazole carboxylic acid to form a metal-organic framework having an at least partially crystalline network having a plurality of internal pores defined therein and comprising a multidentate organic ligand comprising a plurality of metal clusters coordinated to the 4-pyrazole carboxylate, the plurality of metal clusters comprising one or more MO clusters, where M is a metal, wherein the at least partially crystalline network has an X-ray powder diffraction pattern comprising characteristic diffraction peaks consistent with Pa3 symmetry.

[0006] In yet other embodiments, the methods of the disclosure may include contacting a mixture comprising one or more chemical species with a metal-organic framework comprising a plurality of metal clusters comprising one or more MO (wherein M is a metal) clusters and a plurality of multidentate organic ligands coordinated to the plurality of metal clusters to define an at least partially crystalline network having a plurality of internal pores, the multidentate organic ligands comprising 4-pyrazole carboxylate, the at least partially crystalline network having an X-ray powder diffraction pattern comprising characteristic diffraction peaks at least 8.91, 9.96, 10.9, and 12.6 (all ±5%) degrees two theta (°2θ); and absorbing at least a portion of the one or more chemical species into at least a portion of the internal pores. In yet another embodiment, the method of the present disclosure may include providing a catalyst precursor comprising the reaction product of 4-pyrazole carboxylic acid and preformed metal clusters, the reaction product having an at least partially crystalline network having a plurality of internal pores defined therein, and comprising a plurality of metal clusters including one or more MO clusters (M is a metal) coordinated to the 4-pyrazole carboxylate, the at least partially crystalline network having an X-ray powder diffraction pattern including characteristic diffraction peaks consistent with Pa3 symmetry; exposing the catalyst precursor to a reducing agent to form an activated catalyst; contacting the activated catalyst with an olefin; and hydrogenating the olefin while the olefin is in contact with the activated catalyst.

[0007] BRIEF DESCRIPTION OF THE DRAWINGS The following figures are included to illustrate certain aspects of the present disclosure and should not be considered as exclusive embodiments. The disclosed subject matter is capable of considerable modification, alteration, combinations, and equivalents in form and function, as will be apparent to those skilled in the art and having the benefit of this disclosure. [Brief description of the drawings]

[0008] [Figure 1] 1 shows the X-ray powder diffraction pattern for the MOF obtained in Example 1A. [Diagram 2] In Example 1A, X-ray diffraction patterns are shown for the MOF obtained after exposure to atmospheric water for 3 days (lower pattern) and after heating at 150° C. for 60 min under flowing nitrogen (upper pattern). [Diagram 3] FIG. 1 shows comparative X-ray powder diffraction patterns for the as-prepared and dried product of Example 1A, MOF-5, and Zn4O(PyCO2)3. [Figure 4A] 1 shows the N2 adsorption isotherm at 77 K (25° C.) plotted on the P / P0 scale for the MOF of Example 1A. [Figure 4B] 1 shows the N2 adsorption isotherm at 77 K (25° C.) for the MOF of Example 1A plotted on the Log P / P0 scale. [Diagram 5]1 shows the H2 adsorption / desorption isotherm for the MOF of Example 1A at 7 K (-14 °C). [Figure 6] 1 shows the hydrocarbon (CH4, C2H4, C2H6, C3H8, C3H6) adsorption isotherms for the MOF of Example 1A at 303 K (151 °C). [Figure 7] 1 shows the X-ray powder diffraction pattern of the MOF obtained in Example 1C after ammonia addition was completed but before lyophilization. [Figure 8] 1 shows the N2 adsorption isotherms at 77 K (25° C.) for the MOF of Example 1C plotted on the P / P0 and Log P / P0 scales, respectively. [Figure 9] 1 shows comparative X-ray powder diffraction patterns of the product of Example 1A and the products of Examples 3A, 3B, and 3C. [Figure 10A] 1 shows an energy dispersive X-ray analysis of the product of Example 3A. [Figure 10B] 1 shows an energy dispersive X-ray analysis of the product of Example 3B. [Figure 10C] 1 shows an energy dispersive X-ray analysis of the product of Example 3C. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Detailed Description The present disclosure relates to MOFs formed from pyrazolylcarboxylate ligands. As briefly discussed above, MOFs can be synthesized by reacting polydentate organic ligands with a suitable metal source to form crystalline or partially crystalline networks with multiple internal pores. The networks may in some cases constitute coordination polymers. The structure and properties of MOFs can be tuned by the choice of polydentate organic ligands and metals or metal sources. As highly porous materials, MOFs can selectively adsorb and / or separate various types of gases, molecules or other chemical entities. As such, MOFs have potential applications including gas storage and separation. However, the chemical stability of many conventional MOFs hampers the ability to exploit their porous structure.

[0010] The present disclosure provides MOFs that are easily accessible and include multidentate organic ligands with different binding sites. In particular, the multidentate organic ligands utilized in the present disclosure include a pyrazolyl moiety as a first binding site and a carboxylate moiety as a second binding site. The pyrazolyl moiety of the multidentate organic ligand can include various substituents. Surprisingly, the multidentate organic ligands described herein can provide materials with a network structure that features a cubic topology and exhibits dynamic solvation states that result in changes in the symmetry of solvated and unsolvated materials. The incorporation of pyrazolyl carboxylate ligands also provides improved aqueous stability, improved capacity for post-synthetic modification, and easier synthesis by cluster-based approaches compared to MOF-5. Surprisingly, MOFs synthesized according to the present disclosure have significantly different X-ray powder diffraction than those synthesized using a different synthetic procedure with the same pyrazole carboxylate ligand (Tu et al., J. Am. Chem. Soc., 2014, 136, 14465), suggesting that different MOF structures are formed using the metal sources disclosed herein.

[0011] In a particular embodiment, the polydentate organic ligand of the present disclosure can include 4-pyrazole carboxylate. As further discussed herein, this polydentate organic ligand can react with various metal sources to form MOFs with advantageous properties. A more specific embodiment of the MOF can include a plurality of zinc centers or zinc clusters and a 4-pyrazole carboxylate polydentate organic ligand that is coordinated to the plurality of zinc centers or zinc clusters through at least one binding site to define an at least partially crystalline network structure with a plurality of internal pores. Surprisingly, 4-pyrazole carboxylates and similar polydentate organic ligands can form MOFs with variable network structures depending on the metal source and reaction conditions (e.g., concentration, temperature, and time) used. In some cases, preformed metal clusters, such as Zn4O(2,2-dimethylbutanoate)6 (Zn4O(DMBA)6) or similar metal carboxylate clusters, may be particularly suitable for reacting with the pyrazolyl carboxylate ligands described above to form MOFs. Although preformed metal clusters may be a particularly desirable metal source to facilitate the formation of MOFs, other metal sources may also be successfully used when forming MOFs without dynamic solvation states. The ability of the pyrazolyl carboxylate ligands described herein to form stable MOFs is believed to be due to the structural strength of the robust metal-ligand bond, as well as the positioning of binding sites that efficiently promote large cubic pores by coordination of metal clusters to pyrazolate and carboxylate moieties.

[0012] In addition to the above, MOFs synthesized using the polydentate organic ligands described herein can undergo exchange with other metals to replace at least a portion of the metal atoms of the metal centers or metal clusters with one or more different metals. One or more different metals can be introduced for any purpose, such as to provide additional structural stabilization or to promote catalytic reactions. In many cases, minimal structural reorganization occurs when metal exchange is performed. Before describing the various embodiments of the present disclosure in more detail, a list of terms that will be helpful to a better understanding of the present disclosure is provided below. All numerical values ​​in the detailed description and claims of this application are modified by "about" or "approximately" to the stated value to account for experimental error and variations that one of ordinary skill in the art would expect. Unless otherwise specified, room temperature is about 25°C. As used in this disclosure and claims, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates otherwise. As used herein in expressions such as "A and / or B," the term "and / or" includes "A and B," "A or B," "A," and "B."

[0013] For the purposes of this disclosure, a new numbering scheme for the groups of the periodic table is used in which the groups (columns) are numbered consecutively from left to right from 1 to 18, with the exception of the f-block elements (lanthanides and actinides). As used in this disclosure and in the claims, Me is methyl, Et is ethyl, Pr is propyl, cPr is cyclopropyl, nPr is n-propyl, iPr is isopropyl, Bu is butyl, nBu is normal butyl, iBu is isobutyl, sBu is sec-butyl, tBu is tert-butyl, Cy is cyclohexyl, Oct is octyl, Ph is phenyl, and Bn is benzyl.

[0014] The term "hydrocarbon" refers to a class of compounds having hydrogen bonded to carbon and includes (i) saturated hydrocarbon compounds, (ii) unsaturated hydrocarbon compounds, and (iii) mixtures of hydrocarbon compounds (saturated and / or unsaturated), including mixtures of hydrocarbon compounds having different numbers of carbon atoms. n " refers to a hydrocarbon or hydrocarbyl group having n carbon atoms per molecule or group, where n is a positive integer. The hydrocarbon compound may be one or more of straight chain, branched chain, cyclic, acyclic, saturated, unsaturated, aliphatic, or aromatic, and may optionally be substituted. The terms "hydrocarbyl" and "hydrocarbyl group" are used interchangeably herein. The term "hydrocarbyl group" refers to any C1-C6 alkyl group that, when removed from a parent compound, has at least one vacant valence position. 100 The term "hydrocarbyl group having from 1 to about 100 carbon atoms" also refers to a straight or branched chain C1-C 100 Alkyl, C3-C 100 Cycloalkyl, C6-C 100 Aryl, C2-C 100 Heteroaryl, C1-C100 Alkylaryl, C7-C 100 arylalkyl, and any combination thereof.

[0015] The term "substituted" refers to the replacement of at least one hydrogen or carbon atom of a hydrocarbon or hydrocarbyl group with a heteroatom or heteroatom functional group. Heteroatoms include, but are not limited to, B, O, N, S, P, F, Cl, Br, I, Si, Pb, Ge, Sn, As, Sb, Se, and Te. Heteroatom functional groups that may be present in a substituted hydrocarbon or hydrocarbyl group include, but are not limited to, O, S, S=O, S(=O)2, NO2, F, Cl, Br, I, NR2, OR, SeR, TeR, PR2, AsR2, SbR2, SR, BR2, SiR3, GeR3, SnR3, PbR3, and other functional groups, where R is a hydrocarbyl group or H. Suitable hydrocarbyl R groups include alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, heterocyclyl, and the like, all of which may be optionally substituted. The term "optionally substituted" means that the hydrocarbon or hydrocarbyl group may be unsubstituted or substituted. For example, the term "optionally substituted hydrocarbyl" refers to the replacement of at least one hydrogen or carbon atom of a hydrocarbyl group with a heteroatom or heteroatom functional group. Unless otherwise specified, any hydrocarbyl group in this application may be optionally substituted.

[0016] The terms "straight chain" or "straight chain hydrocarbon" refer to a hydrocarbon or hydrocarbyl group having a continuous carbon chain with no branched side chains, which may be optionally substituted. The terms "cyclic" or "cyclic hydrocarbon" refer to a hydrocarbon or hydrocarbyl group having a closed carbon ring, which may be optionally substituted. The term "branched chain" or "branched chain hydrocarbon" refers to a hydrocarbon or hydrocarbyl group having a linear carbon chain or closed carbon ring from which extends hydrocarbyl side chains. Optional substitution may be present on the linear carbon chain, the closed carbon ring, and / or the hydrocarbyl side chain. The terms "saturated" or "saturated hydrocarbon" refer to a hydrocarbon or hydrocarbyl group in which all carbon atoms are bonded to four other atoms, except for any vacant valence position present on a carbon atom in the hydrocarbyl group. The term "unsaturated" or "unsaturated hydrocarbon" refers to a hydrocarbon or hydrocarbyl group in which one or more carbon atoms are bonded to fewer than four other atoms, excluding any vacant valence positions present on the carbon. That is, the term "unsaturated" refers to a hydrocarbon or hydrocarbyl group having one or more double and / or triple bonds, where the double and / or triple bonds are between two carbon atoms and / or between a carbon atom and a heteroatom.

[0017] The terms "aromatic" or "aromatic hydrocarbon" refer to a hydrocarbon or hydrocarbyl group having a cyclic arrangement of conjugated pi electrons that satisfies Huckel's rule. The term "alkyl" refers to a hydrocarbyl group that has no unsaturated carbon-carbon bonds and may be optionally substituted. The terms "alkene" and "olefin" are used interchangeably herein. Similarly, the terms "alkenic" and "olefinic" are used interchangeably herein. Unless otherwise specified, these terms include all possible geometric isomers. The term "aryl" is equivalent to the term "aromatic" as defined herein. The term "aryl" refers to both aromatic and heteroaromatic compounds, which may be optionally substituted. These terms include both mononuclear and polynuclear aromatic compounds. The terms "heteroaryl" and "heteroaromatic" refer to aromatic rings that contain heteroatoms and satisfy Huckel's rule.

[0018] Examples of aromatic hydrocarbyl groups include, but are not limited to, phenyl, tolyl, xylyl, naphthyl, etc. Heteroaryl and polynuclear heteroaryl groups include, but are not limited to, pyridyl, quinolinyl, isoquinolinyl, pyrimidinyl, quinazolinyl, acridinyl, pyrazinyl, quinoxalinyl, imidazolyl, benzimidazolyl, pyrazolyl, benzopyrazolyl, oxazolyl, benzoxazolyl, isoxazolyl, benzoisoxazolyl, imidazolinyl, thiophenyl, benzothiophenyl, furanyl, and benzofuranyl. Polynuclear aryl groups include, but are not limited to, naphthalenyl, anthracenyl, indanyl, indenyl, and tetralinyl.

[0019] As used herein, the term "multidentate" refers to a compound that has two or more potential sites for coordination to a metal center. Thus, the term "multidentate" refers to bidentate, tridentate, tetradentate, and higher dentate ligands. The term "metal center" refers to a single metal atom or metal ion, or a group of metal atoms and / or metal ions, to which a ligand is coordinated. The term "metal cluster" refers to a group of metal atoms and / or metal ions bonded together.

[0020] The term "secondary building unit" refers to a metal cluster coordinated by two or more polydentate organic ligands. For example, a secondary building unit may have the formula MO and may be coordinated to a polydentate organic ligand, such as a carboxylate group, to form a MOF having a polymetallic carboxylate cluster of the formula MO(CO). Clusters MO may also be coordinated to form MOFs by bidentate groups, including carboxylate or hydrazyl groups. The term "preformed metal cluster" refers to a group of multiple metal atoms and / or metal ions and one or more ligands that are synthesized before being combined with other materials to form a MOF. The term "at least partially crystalline" means that the material exhibits an X-ray powder diffraction pattern. The term "binding site" refers to a chemical entity capable of coordinating to a metal center via a metal-ligand bond. The term "activation" refers to the removal of the balancing molecular charge of a solvent molecule or species by heating and / or elimination.

[0021] Thus, the MOFs of the present disclosure may comprise a plurality of metal centers or clusters and a plurality of multidentate organic ligands coordinated to the plurality of metal centers or clusters to define an at least partially crystalline network having a plurality of internal pores. The multidentate organic ligand comprises 4-pyrazole carboxylate. The MOFs disclosed herein may be morphologically distinct from previous MOFs incorporating 4-pyrazole carboxylates (see Tu et al., J. Am. Chem. Soc., 2014, 136, 14465) when an appropriate metal source is used. In particular, the MOFs disclosed herein may be characterized by an at least partially crystalline network exhibiting characteristic X-ray powder diffraction peaks at least 8.91, 9.96, 10.9, and 12.6 (all ±5%) degrees two theta (2θ). Other distinguishing features may include the space group of the MOF (space group Pa3 in the case of the MOFs disclosed herein). The MOFs may transition between space groups by solvation or desolvation. Formula 1 below shows the chemical structure of 4-pyrazole carboxylic acid that can be incorporated as a multidentate organic ligand into the MOFs of the present disclosure.

[0022] [ka]

[0023] The identity of the metal centers or metal clusters that may be present in the MOFs disclosed herein is not intended to be particularly limited. In some embodiments, at least a portion of the metal clusters may include one or more metal centers having a tetrahedral structure. In some embodiments, at least a portion of the metal centers or metal clusters may include a divalent metal. In some cases, a trivalent metal may be included alone or in combination with one or more divalent metals as appropriate. Suitable divalent metals that may be present in the MOFs disclosed herein include, for example, zinc, cobalt, nickel, copper, iron, chromium, manganese, or any combination thereof. The metals that make up the metal centers or metal clusters may be introduced by reacting a suitable metal source with the polydentate organic ligands described above, or at least a portion of the metals in the metal centers or metal clusters may be introduced by exchange reactions after forming the at least partially crystalline network that defines the MOF. In certain embodiments, the metal clusters may be in the form of one or more MO clusters, where M is a metal.

[0024] In some embodiments, preformed metal clusters can be suitable metal sources for forming the MOFs disclosed herein. Determining the presence of networks and their crystallinity, including determining whether a particular network is associated with another network, can be accomplished by X-ray powder diffraction, as described elsewhere herein. One example of a suitable preformed metal cluster that can be used to facilitate the formation of MOFs with the polydentate organic ligands described herein is a zinc cluster represented by the formula Zn4O(2,2-dimethylbutanoic acid)6 (Zn4O(DMBA)6). Thus, even more specific MOFs of the present disclosure may include a plurality of metal clusters and 4-pyrazole carboxylates coordinated to the plurality of metal clusters to define an at least partially crystalline network having a plurality of internal pores, the plurality of metal clusters including one or more MO clusters. In an even more specific example, the MOF may include a plurality of zinc clusters and 4-pyrazole carboxylates coordinated to the plurality of zinc clusters to define an at least partially crystalline network having a plurality of internal pores. The MOF may be characterized by the characteristic X-ray powder diffraction peaks described above. In some or other more specific embodiments, the MOFs of the present disclosure that include a plurality of zinc clusters may further include a plurality of nickel centers that are also coordinated to the 4-pyrazole carboxylate ligands via at least one binding site. The nickel center may be introduced via metal exchange with at least some of the zinc.

[0025] MOFs formed according to the present disclosure, particularly those formed from 4-pyrazole carboxylates as polydentate organic ligands, can be characterized with respect to their internal porosity. MOFs of the present disclosure can include micropores, mesopores, macropores, and any combination thereof. Micropores are defined herein as having a pore size of about 2 nm or less, and mesopores are defined herein as having a pore size of about 2 nm to about 50 nm. Determination of microporosity and / or mesoporosity can be performed by analysis of nitrogen adsorption isotherms at 77 K (25° C.), as will be appreciated by those of skill in the art. The internal pore volume and other morphological characteristics of MOFs can be determined from nitrogen adsorption isotherms as well, as will be appreciated by those of skill in the art. As a non-limiting example, MOFs formed according to the present disclosure can exhibit pore volumes of up to 0.582 cc / g and micropore volumes of up to 0.45 cc / g. 2 / g micropore surface area of ​​1257 m 2Total surface areas of up to 906 m / g are achievable. In these embodiments, pore radii of about 4.1 Å can be identified by DFT analysis of the nitrogen adsorption isotherms. In some embodiments, in addition to these micropores, mesopores with pore radii of about 20 Å can be identified. The total pore volume contribution from these mesopores can be significant, providing about half of the total pore volume. Total pore volumes of up to 0.64 cc / g can be observed, with 0.34 cc / g of micropore volume contributing to this total. In these highly mesoporous materials, pore radii of up to 906 m / g can be achieved. 2 Surface areas of up to 717m / g may be observed. 2 / g is the micropore surface area.

[0026] The metal organic frameworks of the present disclosure, as synthesized, can exhibit X-ray powder diffraction patterns consistent with a cubic unit cell with systematic absences of the Pa3 space group. Under the analytical conditions, there is consensus that other space groups with similar symmetry operators and extinction rules may exist that cannot be distinguished by laboratory-based X-ray diffraction techniques. Upon activation (i.e., removal of the solvent by heating and / or evacuation), the X-ray powder diffraction peaks at 7.73, 9.95 and 10.9°2θ are all attenuated and may disappear completely. In addition to the disappearance of these peaks, peaks at approximately 14.5 and 19°2θ appear. In combination, the symmetry of the observed powder pattern is consistent with a higher symmetry, specifically the Fm3m unit cell. This change in symmetry is reversible, with the reappearance of the apparent Pa3 space group as a result of the introduction of a solvent such as dimethylformamide or ethanol. Drying again results in the Fm3m space group. On a structural level, the conversion of the material between Pa3 and Fm3m may result in the loss of symmetry equivalence of one of the four structural zinc cations that comprise the secondary structural units of the zinc cluster.

[0027] The present application also describes methods for synthesizing the MOFs of the present disclosure. Some syntheses can be advantageously performed using preformed metal clusters as the metal source, as described above, although other metal sources may be used, including some monometallic salts. Advantageously, the metal source can be selected to obtain MOFs with related, but slightly different, network structures. Thus, the selection of the metal source used in the synthesis of the MOFs disclosed herein can allow the network structure to be tailored to achieve compatibility with a particular application. Thus, certain methods of the present disclosure may include combining a metal source with 4-pyrazole carboxylic acid and reacting the metal source with the 4-pyrazole carboxylic acid to form a metal-organic framework having at least a partially crystalline network with multiple internal pores defined therein and including multiple metal centers or metal clusters coordinated to a multidentate organic ligand including 4-pyrazole carboxylate. The MOF may be defined by the characteristic X-ray powder diffraction peaks described above, particularly that characteristic of Pa3 symmetry. In more specific embodiments, the metal source may be a preformed metal cluster, such as a preformed metal cluster including zinc, more particularly Zn4O(2,2-dimethylbutanoate)6 or a similar metal carboxylate cluster. MOFs prepared using metal carboxylate clusters may be advantageous in that they also allow for a greater variety of synthesis conditions while facilitating more reproducible and higher yield synthesis. Metal carboxylate clusters may also provide different structural behavior that may not be observed when using other metal sources.

[0028] In some embodiments, the removal of residual ligands, metal salts, or solvents incorporated in the internal pores from the MOFs disclosed herein can be observed as a change in symmetry in the X-ray diffraction pattern of the MOF. For example, when residual ligands, metal salts, or solvents are removed, the MOFs disclosed herein can change from a cubic m-3 Laue class to a cubic m-3m Laue class. More specifically, the change in symmetry due to solvation and / or desolvation of the MOFs disclosed herein is a change from a cubic Pa3 space group to a cubic Fm-3m space group. Without being bound by theory or mechanism, it is believed that this ability to change symmetry is related to the formation of kinetic products that can undergo this symmetry change as a result of using preformed zinc clusters, as opposed to thermodynamic products resulting from the use of zinc salts.

[0029] In some embodiments, residual ligands, such as 2,2-dimethylbutanoic acid or its salts, or metal salts, or solvents, can be thermally removed from the multiple internal pores. Sufficiently elevated temperatures can volatilize or possibly thermally decompose the residual ligands above their boiling points. In exemplary embodiments, thermal removal of the residual ligands is performed at a temperature of at least about 100° C., or at least about 150° C., or at least about 200° C., or at least about 450° C. Selection of a suitable temperature for thermal removal of the residual ligands can be determined by the boiling points of the residual ligands, their thermal stability, and / or the thermal stability of the MOF itself. Some or other methods of the present disclosure may include exchanging at least a portion of the first metal cations that make up the plurality of metal centers or metal clusters with a second metal cation. For example, according to various embodiments of the present disclosure, at least a portion of the zinc cations that make up the metal clusters may be exchanged with nickel cations. Metal cation exchange may be affected by contacting the MOF with, for example, a salt solution.

[0030] Certain metal organic frameworks of the present disclosure may have catalytic properties by themselves or after activation in the presence of a suitable activating material. One particular example of a catalytic metal organic framework may include the reaction product of 4-pyrazole carboxylic acid with preformed zinc clusters, in particular Zn4O(2,2-dimethylbutanoic acid)6, in which at least a portion of the metal clusters include one or more metal centers that include zinc, and at least a portion of the zinc has been exchanged with a catalytically active metal, such as nickel. Thus, the catalyst system of the present disclosure may include a catalyst precursor comprising the metal organic framework, which may be activated via chemical treatment with a reducing agent, such as molecular hydrogen, and the activated catalyst may be used to reduce organic olefinic compounds, such as ethylene, to give saturated products. Thus, some methods of the present disclosure may include contacting a mixture including one or more chemical species with a metal-organic framework including a plurality of metal centers or clusters including one or more MO clusters, where M is a metal, and a plurality of polydentate organic ligands coordinated to the plurality of metal centers or clusters to define an at least partially crystalline network having a plurality of internal pores, the polydentate organic ligands including 4-pyrazole carboxylate, and absorbing at least a portion of the one or more chemical species into at least a portion of the plurality of internal pores. The at least partially crystalline network includes the characteristic diffraction peaks described above and / or has an X-ray powder diffraction pattern consistent with Pa3 symmetry.

[0031] Similarly, some or other methods of the present disclosure may include providing a catalyst precursor comprising the reaction product of 4-pyrazole carboxylic acid and preformed metal clusters, the reaction product being a metal-organic framework comprising a plurality of metal clusters including one or more MO clusters (M is a metal) coordinated to the 4-pyrazole carboxylic acid, the reaction product having an at least partially crystalline network having a plurality of internal pores defined therein; exposing the catalyst precursor to a reducing agent to form an activated catalyst; contacting the activated catalyst with an olefin; and hydrogenating the olefin while the olefin is in contact with the activated catalyst. The at least partially crystalline network comprises the characteristic X-ray powder diffraction peaks described above and / or has an X-ray powder diffraction pattern consistent with Pa3 symmetry.

[0032] The embodiments disclosed in this application include the following. A. A MOF having 4-pyrazole carboxylate ligands, the MOF comprising a plurality of metal clusters comprising one or more MO clusters, where M is a metal, and a plurality of multidentate organic ligands coordinated to the plurality of metal clusters to define a partially crystalline network having a plurality of interior pores, the multidentate organic ligands comprising 4-pyrazole carboxylate, the at least partially crystalline network having an X-ray powder diffraction pattern including characteristic diffraction peaks consistent with Pa3 symmetry. B. MOF Having 4-pyrazole carboxylate Ligand and Comprising Characteristic Diffraction Peaks: The MOF comprises a plurality of metal clusters comprising one or more MO clusters (where M is a metal) and a plurality of multidentate organic ligands coordinated to the plurality of metal clusters to define an at least partially crystalline network having a plurality of internal pores, the multidentate organic ligands comprising 4-pyrazole carboxylate, and the at least partially crystalline network has an X-ray powder diffraction pattern comprising characteristic diffraction peaks at least 8.91, 9.96, 10.9 and 12.6 (all ±5%) degrees two theta (°2θ).

[0033] C. A method for making a MOF having a 4-pyrazole carboxylate ligand, the method comprising combining a preformed metal cluster with 4-pyrazole carboxylic acid, and reacting the preformed metal cluster with the 4-pyrazole carboxylic acid to form a metal organic framework having an at least partially crystalline network having a plurality of interior pores defined therein and comprising a plurality of metal clusters coordinated to 4-pyrazole carboxylate, the plurality of metal clusters comprising one or more MO clusters, where M is a metal, the at least partially crystalline network having an X-ray powder diffraction pattern including characteristic diffraction peaks consistent with Pa3 symmetry. D. Method for making an MOF having 4-pyrazole carboxylate ligands and comprising characteristic diffraction peaks, the method comprising combining a metal source with 4-pyrazole carboxylic acid and reacting the metal source with the 4-pyrazole carboxylic acid to form a metal organic framework having an at least partially crystalline network having a plurality of internal pores defined therein and comprising a plurality of metal clusters coordinated to a multidentate organic ligand comprising 4-pyrazole carboxylate, the plurality of metal clusters comprising one or more MO clusters, where M is a metal, the at least partially crystalline network having an X-ray powder diffraction pattern comprising characteristic diffraction peaks at least 8.91, 9.96, 10.9 and 12.6 (all ±5%) degrees two theta (°2θ).

[0034] E. Catalytic Method. The method includes providing a catalyst precursor comprising the reaction product of 4-pyrazole carboxylic acid and preformed metal clusters, the reaction product having an at least partially crystalline network having a plurality of interior pores defined therein, and a metal-organic framework comprising a plurality of metal clusters including one or more MO clusters (wherein M is a metal) coordinated to the 4-pyrazole carboxylate, the at least partially crystalline network having an X-ray powder diffraction pattern including characteristic diffraction peaks consistent with Pa3 symmetry, exposing the catalyst precursor to a reducing agent to form an activated catalyst, contacting the activated catalyst with an olefin, and hydrogenating the olefin while the olefin is in contact with the activated catalyst. F. A Separation Method, the method comprising contacting a mixture comprising one or more chemical species with a metal-organic framework comprising a plurality of metal clusters comprising one or more MO clusters, where M is a metal, and a plurality of polydentate organic ligands coordinated to the plurality of metal clusters to define an at least partially crystalline network having a plurality of internal pores, the polydentate organic ligands comprising 4-pyrazole carboxylate, the at least partially crystalline network having an X-ray powder diffraction pattern comprising characteristic diffraction peaks at least 8.91, 9.96, 10.9 and 12.6 (all ±5%) degrees two theta (°2θ), and absorbing at least a portion of the one or more chemical species into at least a portion of the internal pores.

[0035] Embodiments A through F may have one or more of the following additional elements in any combination: Element 1: The at least partially crystalline network has a cubic topology. Element 2: The at least partially crystalline network has Pa3 symmetry. Element 3: At least a portion of the plurality of metal clusters includes one or more metal centers having a tetrahedral structure. Element 4: At least a portion of the plurality of metal clusters comprises a divalent metal. Element 5: At least a portion of the plurality of metal clusters comprises zinc, cobalt, nickel, copper, iron, chromium, manganese, or any combination thereof. Element 6: At least a portion of the plurality of metal clusters comprises zinc. Element 7: The at least partially crystalline network comprises Zn4O clusters. Element 8: The metal organic framework is the reaction product of a preformed metal cluster and 4-pyrazole carboxylate. Element 9: Preformed metal clusters include Zn4O(2,2-dimethylbutanoate)6. Element 10: The internal pore has a pore diameter in the range of about 6.0 Å to about 40 Å. Element 11: The internal pores have a pore volume ranging from about 0.4 cc / g to about 0.64 cc / g. Element 12: At least partially crystalline network of about 750 m 2 / g ~ approx. 1300m 2 / g range of BET surface area.

[0036] Element 13: The metal source is a preformed metal cluster. Element 14: The preformed metal cluster comprises zinc. Element 15: The metal-organic framework comprises at least one of a residual ligand, a metal salt, or a solvent in at least a portion of the plurality of interior pores. Element 16: The method further includes thermally removing residual ligands, metal salts, solvents, or any combination thereof from the plurality of interior pores. Element 17: The symmetry of the metal-organic framework changes upon removal of residual ligands, metal salts, solvents, or any combination thereof. Element 18: The plurality of metal clusters defines a plurality of metal centers, and the method further includes exchanging at least a portion of the first metal of the plurality of metal centers with a second metal. Element 19: The first metal is zinc and the second metal includes at least one of cobalt, nickel, or manganese. Element 20: The one or more chemical species include hydrogen, nitrogen, a hydrocarbon, or a mixture thereof. Element 21: At least a portion of the metal clusters contain zinc, and at least a portion of the zinc is exchanged with a catalytically active metal. Element 22: Catalytically active metals include Ni(II). Element 23: The reducing agent comprises molecular hydrogen.

[0037] As non-limiting examples, typical combinations applicable to A include: 4 and 5; 4 and 6; 4 and 7; 4 and 8; 4 and 9; 4, 9 and 10; 4 and 11; 4 and 12; 5 and 6; 5 and 7; 5 and 8; 5 and 9; 5, 9 and 10; 5 and 11; 5 and 12; 6 and 7; 6 and 8; 6 and 9; 6. 9 and 10; 6 and 11; 6 and 12; 7 and 8; 7 and 9; 7, 9 and 10; 7 and 11; 7 and 12; 8 and 9; 8, 9 and 10; 8 and 11; 8 and 12; 9 and 10; 9 and 11; 9 and 12; 9, 10 and 11; 9, 10 and 12; 11 and 12. Typical combinations applicable to B include: 1 and 2; 1 and 3; 1 and 4; 1 and 5; 1 and 6; 1 and 7; 1 and 8; 1, 8 and 9; 1 and 10; 1 and 11; 1 and 12; 2 and 3; 2 and 4; 2 and 5; 2 and 6; 2 and 7; 2 and 8; 2, 8 and 9; 2 and 10; 2 and 11; 2 and 12; 3 and 4; 3 and 5; 3 and 6; 3 and 8; 3, 8 and 9; 3 and 10; 3 and 11; 3 and 12; 4 and 5; 4 and 6; 4 and 7; 4 and 8; 4, 8 and 9;4 and 10;4 and 11;4 and 12;5 and 6;5 and 7;5 and 8;5, 8 and 9;5 and 10;5 and 11;5 and 12;6 and 7;6 and 8;6, 8 and 9;6 and 10;6 and 11;6 and 12;7 and 8;7, 8 and 9;7 and 10;7 and 11;7 and 12;8 and 9;8 and 10;8 and 11;8 and 12;8, 9 and 10;8, 9 and 11;8, 9 and 12;10 and 11;10 and 12;11 and 12.

[0038] Exemplary combinations applicable to C include: 9 and 14; 9 and 15; 9, 15 and 16; 9, 15 and 17; 9, 16 and 17; 9 and 18; 9 and 19; 14 and 15; 14, 15 and 16; 14, 15 and 17; 14, 16 and 17; 14 and 18; 14 and 19; 15 and 16; 15, 16 and 17; 15 and 18; 15 and 19; 18 and 19. Exemplary combinations applicable to D include: 3 and 13; 3, 13 and 14; 3, 9 and 13; 3 and 15; 3 and 16; 3, 16 and 17; 3 and 18; 3 and 19; 13 and 14; 9 and 13, 13 and 15; 13, 15 and 16; 13 and 17; 13 and 18; 13 and 19; 9 and 14; 14 and 15; 14, 15 and 16; 14 and 17; 14 and 18; 14 and 19; 15 and 16; 15, 16 and 17; 15 and 18; 15 and 19; 15, 16 and 18; 15, 16 and 19; 17 and 18; 17 and 19; 18 and 19. Exemplary combinations applicable to E include 21 and 22; 21 and 23; 22 and 23. To facilitate a better understanding of the embodiments described herein, examples of various representative embodiments are provided below. The following examples should not be construed in any way as limiting or defining the scope of the present disclosure. EXAMPLES

[0039] example The X-ray powder diffraction patterns in the following examples were obtained using Cu-Kα radiation. The BET surface areas in the following examples were determined from N2 adsorption isotherms obtained at 77 K (25 °C). N2 adsorption isotherms were measured using an Autosorb IQ3 analyzer (Quantachrome) at 77 K (25 °C). Prior to the measurements, samples were incubated at 180 °C for 10 min. -5 The sample was degassed for 12 hours to a constant pressure of 1000 torr. The surface area was then measured by the amount of N2 adsorbed on the surface of the sample. Regression analysis was then applied to the data resulting in an isotherm. The isotherm was further analyzed to calculate the micropore volume and other quantities.

[0040] Example 1A: Metal-organic framework synthesis. 4-Pyrazole carboxylic acid (1.7 g) was dissolved in 400 mL of a 20 vol.% aqueous solution in ethanol. The solution was heated to 60° C. and 5.74 g of Zn4O(2,2-dimethylbutanoate)6 (2,2-dimethylbutanoate = DMBA) was added as a solid. Synthesis of Zn4O(DMBA)6 was achieved by literature methods described in MR Gordon, et al., “Preparation and properties of tetrazinc μ4-oxohexa-μ-carboxylates (basic zinc carboxylates),” Can. J. Chem., 1983, pp. 1218-1221, 61. A solid formed immediately upon initiation of the reaction. The reaction was stirred overnight at 60° C. The solid was then isolated by centrifugation and washed with N,N-dimethylformamide (DMF). The isolated solid was resuspended in DMF and heated to 60°C and stirred for an additional 4 h. The solid was isolated by centrifugation and then washed successively with toluene and cyclohexane. Dry powders were isolated by either drying the cyclohexane-wet solid at room temperature or by freezing the solid in a bath at a temperature low enough to freeze a suspension of the MOFs in cyclohexane and then applying a vacuum to remove the cyclohexane by sublimation (lyophilization).

[0041] Example 1B: Metal-organic framework synthesis. The synthesis was identical to that of Example 1A, except that the ethanol / water solvent was replaced with a 70 / 30 volume ratio of N,N-dimethylformamide and water. The solid was then isolated by centrifugation and washed with N,N-dimethylformamide (DMF). The isolated solid was resuspended in DMF, heated to 60° C., and stirred for an additional 4 hours. The solid was isolated by centrifugation and then washed sequentially with ethanol and cyclohexane. The dry powder was isolated by either drying the cyclohexane-wet solid at room temperature or by freezing the solid in a bath at a temperature low enough to freeze a suspension of MOFs in cyclohexane, followed by applying a vacuum to remove the cyclohexane by sublimation (lyophilization).

[0042] Example 1C: Mesopore-containing metal-organic framework synthesis: 4-pyrazole carboxylic acid (3.4 g) was dissolved in 800 mL of a 20 vol.% aqueous solution in ethanol. The solution was heated to 60° C. and 11.4 g of Zn4O(2,2-dimethylbutanoate)6 (2,2-dimethylbutanoate = DMBA) was added as a solid. The reaction started and solids formed immediately. The reaction was stirred at 70° C. overnight. The mixture was then diluted with 480 mL of water. These solids were then filtered and suspended in 200 mL of a 50 / 50 volume mixture of ethanol and water. A small amount (approximately 0.1 mL) of aqueous ammonia was added and the mixture was stirred for 5 minutes. The solids were analyzed by X-ray diffraction until the powder pattern seen in FIG. 7 was observed. The solids were then isolated by centrifugation and washed with ethanol and then cyclohexane. Dry powders were isolated by either drying the cyclohexane-wet solid at room temperature or by freezing the solid in a bath at a temperature low enough to freeze a suspension of the MOFs in cyclohexane and then applying a vacuum to remove the cyclohexane by sublimation (lyophilization).

[0043] Example 2: Characterization of the product. Figure 1 shows the X-ray powder diffraction pattern collected on a Bruker Endeavor D8 X-ray powder diffractometer of the product obtained in Example 1A. Table 1 shows the 2-theta values ​​(°), d-spacing (Å) and relative intensities H (%) of the X-ray powder diffraction peaks of the product obtained in Example 1A.

[0044] [Table 1]

[0045] Table 2 shows the 2 theta values ​​(°), d values ​​(Å) and relative intensities H (%) of the X-ray powder diffraction peaks (FIG. 7) of the product obtained in Example 1C.

[0046] [Table 2]

[0047] Figure 2 shows comparative X-ray powder diffraction patterns of the product obtained in Example 1A after 3 days of exposure to atmospheric water (lower pattern) and after heating to 150°C for 60 minutes under flowing nitrogen (upper pattern). As shown, the decrease in peak intensity is characteristic of increased symmetry. The lower pattern, with its characteristic Pa3 symmetry, transforms to the upper pattern with Fm-3m symmetry after activation under nitrogen. FIG. 3 shows comparative X-ray powder diffraction patterns for the product of Example 1A, MOF-5, and Zn4O(PyCO2)3 (MOF described as compound 1 in Tu et al., J. Am. Chem. Soc., 2014, 136, 14465) as-produced and after drying. The as-synthesized pattern of Zn4O(PyCO2)3 of Tu et al. is clearly different from the product obtained in Example 1A of the present disclosure. Comparing the as-synthesized pattern of Zn4O(PyCO2)3 of Tu et al. with that of the product obtained in Example 1A (FIGS. 1 and 2), it can be seen that the as-synthesized product obtained with metal carboxylate clusters exhibits Pa3 symmetry, indicated by peaks on either side of the parent peak at 9° 2θ. The pattern of the as-synthesized Zn4O(PyCO2)3 of Tu et al. differs from the experimental pattern of the as-synthesized product of Example 1A in that the product obtained in Example 1A shows only a single peak at about 15°2θ as well as four peaks below 12°2θ, which differs from the pattern of the as-synthesized Zn4O(PyCO2)3 of Tu et al., which has a doublet peak at about 15°2θ and only two peaks below 12°2θ.

[0048] 4A and 4B show the N2 adsorption isotherms at 77 K (25 °C) plotted on the P / P0 and Log P / P0 scales, respectively, for the product of Example 1A. The calculated BET surface area is 1257.7 m 2 / g. The external area was 76.4 m 2 / g. The micropore volume was 0.448 cm 3 / g. The corresponding total pore volume was 0.565 cm 3 / g. The micropore surface area was 1181.269 m 2 / g. Figure 5 shows the H2 adsorption / desorption isotherm at 77 K (25 °C) for the product of Example 1A, plotted as mmol / g adsorption on the left axis and wt% adsorption on the right axis. In Figure 5, filled circles represent adsorption and open circles represent desorption. The capacity of this material at 1 bar is comparable to that of MOF-5 on a gravimetric basis and 75% higher on a volumetric basis. FIG. 6 shows the hydrocarbon adsorption isotherms at 303 K (151° C.) for various hydrocarbons for the product of Example 1A. FIG. 7 shows the X-ray powder diffraction pattern of the product of Example 1C after ammonia addition was completed but before lyophilization. FIG. 8 shows the N2 adsorption isotherm at 77 K (25 °C) plotted on the P / P0 and Log P / P0 scales, respectively, for the product of Example 1C. The calculated BET surface area is 908 m 2 / g. The exterior area is 189m 2 / g. The micropore volume was 0.34 cm 3 / g. The corresponding total pore volume was 0.64 cm 3 / g. The micropore surface area was 715 m 2 / g.

[0049] Example 3A: Zinc exchange with CoCl2. 100 mg of the product from Example 1A was dissolved in 10 mL of DMF and 50-200 mg of CoCl2 was added. This solution was then stirred at 60°C for 18 hours. The solid was isolated by centrifugation and washed with DMF (3 x 10 mL). The washed solid was then resuspended in 10 mL of DMF and heated to 60°C with stirring for 4 hours. The material was then isolated by centrifugation and washed with toluene (3 x 10 mL), then cyclohexane, and then air dried. Example 3B: Zinc Exchange with NiCl2 Example 3B was repeated as in Example 3A, except that NiCl2 was used instead of CoCl2. Example 3C: Zinc exchange with MnCl2 Example 3C was repeated as in Example 3A, except that MnCl2 was used instead of CoCl2. Figure 9 shows comparative X-ray powder diffraction patterns of the product of Example 1A and the products of Examples 3A, 3B, and 3C. The three traces of the X-ray powder diffraction pattern for each product (Examples 3A, 3B, and 3C) correspond to the patterns obtained after treatment with, in ascending order, 50, 100, and 150 wt.% of the metal chloride salt. As shown, there was minimal change in the crystallinity and structure of the products after cobalt, nickel, and manganese exchange. 10A-10C show energy dispersive X-ray analyses of the products of Examples 3A, 3B, and 3C, respectively. As shown, the product of Figure 10A contained both cobalt and zinc, suggesting some exchange of zinc centers with cobalt. Table 3 shows the EDX data for the product of Example 3A.

[0050] [Table 3]

[0051] Based on the observed peak areas, the molar ratio of Co:Zn was approximately 1:1, suggesting that some zinc was exchanged for cobalt. The product in Figure 10B contained both nickel and zinc, suggesting some exchange of zinc centers with nickel. Table 4 shows the EDX data for the product of Example 3B.

[0052] [Table 4]

[0053] Based on the observed peak areas, the molar ratio of Ni:Zn was approximately 2:1, suggesting that some zinc was exchanged for nickel. The product in Figure 10C contained both manganese and zinc, suggesting some exchange of zinc centers with manganese. Table 5 shows the EDX data for the product of Example 3C.

[0054] [Table 5]

[0055] Based on the observed peak areas, the molar ratio of Mn:Zn was approximately 1:3, suggesting that some zinc was exchanged for manganese. Example 4A: Zinc exchange with Co(NO3)2. 100 mg of the product from Example 1 was suspended in 10 mL of DMF and 50-200 mg of Co(NO3)2 was added. This solution was then stirred at 60°C for 72 hours. The solid was isolated by centrifugation and washed with DMF (3 x 10 mL). The washed solid was then resuspended in 10 mL of DMF and heated to 60°C with stirring for 4 hours. The material was then isolated by centrifugation and washed with toluene (3 x 10 mL), then cyclohexane, and then air dried. Example 4B: Zinc exchange with Ni(NO3)2. Example 4A was repeated in the same manner, except that Ni(NO3)2 was used instead of Co(NO3)2. Example 4C: Zinc exchange with Mn(NO3)2. Example 4A was repeated except that Mn(NO3)2 was used instead of Co(NO3)2.

[0056] Nickel-exchanged Zn after activation at 150°C under dynamic vacuum 4-x Ni x O(PyCO2)3 showed certain visual differences depending on the nickel source used to promote the metal exchange. Samples using Ni(NO3)2 (Example 4B) and NiCl2 (Example 3B) for exchange were isostructural but showed visual differences in the chemical environment of the metal centers that were not detectable by X-ray powder diffraction. NiCl2 exchanged samples showed a pink color, whereas Ni(NO3)2 exchanged samples were off-white after activation. In the product obtained with nickel nitrate, the metal adopts a tetrahedral structure, which is presumed to result in the pink color of the product.

[0057] Example 5: Hydrogenation of ethylene using the product of 4B. The product of Example 4B was tested for catalytic activity using ethylene hydrogenation. The product powder was loaded into a vertical stainless steel tube reactor and heated using a resistance heating furnace. Mass flow controllers were used to control the flow rates of ethylene, H2, and inert gas (He). The product concentration was quantified by gas chromatography using an Agilent 7890B instrument and a GasPro column. 15 mg of the MOF of Example 4B was loaded into the reactor and heated at 1.7 psi (1.2 x 10 4 Pa) of ethylene and 10 psi (6.9 x 10 4 The gas flow rate was set to give 1000 s of H2 (1 Pa). The furnace temperature was increased and the gas composition was analyzed to look for evidence of ethylene hydrogenation. The MOFs had negligible hydrogenation activity below 250 °C. At 280 °C, the conversion of ethylene to ethane increased rapidly, reaching about 80% conversion. Above 280 °C, ethylene conversion increased steadily, eventually reaching nearly 100% conversion without signs of deactivation over several hours of activity. No other products (e.g., methane) were detected. This suggests that the MOFs are selective hydrogenation catalysts and do not catalyze undesired hydrocracking reactions.

[0058] All documents described herein, including any priority documents and / or testing procedures, are incorporated herein by reference to the extent that they do not conflict with this text for purposes of all jurisdictions where such practice is permitted. As is apparent from the general description and specific embodiments above, the forms of the disclosure have been illustrated and described, but various modifications can be made without departing from the spirit and scope of the disclosure. Accordingly, it is not intended that the disclosure be limited thereby. For example, the compositions described herein may be free of any component or composition not expressly listed or disclosed herein. Any method may be devoid of any step not expressly listed or disclosed herein. Similarly, the term "comprising" is considered synonymous with the term "including". Whenever a method, composition, element, or group of elements is preceded by the traditional phrase "comprising," it is understood that we also contemplate the same composition or group of elements with the traditional phrase "consisting essentially of," "consisting of," "selected from the group consisting of," or "is" preceding the composition, element, or list of elements, and vice versa.

[0059] Unless otherwise indicated, all numbers used in the specification and appended claims expressing the quantities of ingredients, quantities of properties such as, e.g., molecular weight, reaction conditions, and the like, are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending upon the desired properties sought to be obtained by embodiments of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Whenever a numerical range with a lower and upper limit is disclosed, any numerical value falling within the range and any encompassing range are also expressly disclosed. In particular, any range value disclosed herein (in the form "about a to about b," or, similarly, "about a to b," or, similarly, "about a b") should be understood to specify any numerical value and range encompassed within the broader range of values. Furthermore, the terms in the claims have their plain ordinary meaning unless expressly and unambiguously defined otherwise by the patentee. Furthermore, the indefinite article "a" or "an" used in the claims is defined herein to mean one or more elements that it introduces.

[0060] One or more example embodiments are presented herein. For the sake of clarity, not all features of a physical implementation are described or shown in this application. It is understood that in developing a physical embodiment of the present disclosure, numerous implementation-specific decisions must be made to achieve developer goals, such as compliance with system-related, business-related, government-related and other constraints that vary from implementation to implementation and from time to time. While the developer's efforts may be time consuming, the efforts would nevertheless be routine for one of ordinary skill in the art and having the benefit of this disclosure to undertake. Thus, the present disclosure is well adapted to attain the ends and advantages mentioned as well as those inherent therein. The specific embodiments described above are illustrative only, as the disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art and having the benefit of the teachings herein. Moreover, there is no intention to be limited to the details of construction or design shown herein, other than as described in the claims that follow. The specific exemplary embodiments described above may thus be altered, combined or modified, and all such variations are deemed to be within the scope and spirit of the present disclosure. The embodiments disclosed herein as examples may suitably be practiced in the absence of any element not specifically disclosed herein and / or any optional element disclosed herein. Yet another aspect of the present invention may be as follows. [1] A metal-organic framework comprising: One or more M 4 a plurality of metal clusters including an O cluster (wherein M is a metal); a plurality of multidentate organic ligands coordinated to the plurality of metal clusters to define an at least partially crystalline network having a plurality of interior pores, the multidentate organic ligands comprising 4-pyrazole carboxylate; the metal-organic framework, wherein the at least partially crystalline network has an X-ray powder diffraction pattern including characteristic diffraction peaks consistent with Pa3 symmetry. [2] A metal-organic framework comprising: One or more M 4 a plurality of metal clusters including an O cluster (wherein M is a metal); a plurality of multidentate organic ligands coordinated to the plurality of metal clusters to define an at least partially crystalline network having a plurality of interior pores, the multidentate organic ligands comprising 4-pyrazole carboxylate; The metal-organic framework, wherein the at least partially crystalline network has an X-ray powder diffraction pattern including characteristic diffraction peaks at least 8.91, 9.96, 10.9, and 12.6 (all ±5%) degrees two theta (°2θ). [3] The metal-organic framework according to [2], wherein the at least partially crystalline network structure has a cubic topology. [4] The metal-organic framework according to [2] or [3], wherein the at least partially crystalline network structure has Pa3 symmetry. [5] The metal organic framework according to any one of the above [2] to [4], wherein at least a part of the plurality of metal clusters includes one or more metal centers having a tetrahedral structure. [6] The metal organic structure according to any one of the above [2] to [5], wherein at least a part of the plurality of metal clusters contains a divalent metal. [7] The metal organic structure according to any one of the above [2] to [6], wherein at least a part of the plurality of metal clusters contains zinc, cobalt, nickel, copper, iron, chromium, manganese, or any combination thereof. [8] The metal organic structure according to any one of the above [2] to [7], wherein at least a part of the plurality of metal clusters contains zinc. [9] The at least partially crystalline network structure is Zn 4 The metal-organic framework according to any one of the above [2] to [8], which contains an O cluster.

[10] The metal-organic framework according to any one of the above [2] to [9], wherein the metal-organic framework is a reaction product of a preformed metal cluster and the 4-pyrazole carboxylate.

[11] The preformed metal cluster is Zn 4 O(2,2-dimethylbutanoate) 6 The metal-organic framework according to

[10] above,

[12] The metal organic structure according to any one of the above [2] to

[11] , wherein the internal pores have a pore diameter in the range of about 6.0 Å to about 40 Å.

[13] The metal organic structure according to any one of the above [2] to

[12] , wherein the internal pores have a pore volume in the range of about 0.4 cc / g to about 0.64 cc / g.

[14] The at least partially crystalline network structure has a thickness of about 750 mm. 2 / g ~ approx. 1300m 2 The metal organic structure according to any one of the above [2] to

[13] , having a BET surface area in the range of 1 / g.

[15] The following: combining a metal source with 4-pyrazole carboxylic acid; and The metal source is reacted with the 4-pyrazole carboxylic acid to form an at least partially crystalline network having a plurality of internal pores defined therein, the network comprising a plurality of metal clusters coordinated to a multidentate organic ligand comprising 4-pyrazole carboxylate, the plurality of metal clusters being one or more M 4 forming a metal organic framework comprising an O cluster, where M is a metal; A method comprising: The method, wherein the at least partially crystalline network has an X-ray powder diffraction pattern including characteristic diffraction peaks at least 8.91, 9.96, 10.9 and 12.6 (all ±5%) degrees two theta (°2θ).

[16] The method according to

[15] , wherein at least a portion of the plurality of metal clusters includes one or more metal centers having a tetrahedral structure.

[17] The method according to any one of

[15] to

[16] above, wherein the metal source is a preformed metal cluster.

[18] The method according to

[17] , wherein the preformed metal clusters comprise zinc.

[19] The preformed metal cluster is Zn 4 O(2,2-dimethylbutanoate) 6 The method according to claim 17 or 18, comprising:

[20] The method according to any one of

[15] to

[19] above, wherein the metal-organic framework contains at least one of a residual ligand, a metal salt, or a solvent in at least a portion of the multiple internal pores.

[21] Furthermore: thermally removing said residual ligands, metal salts, solvents, or any combination thereof from said plurality of interior pores. The method according to claim 20, comprising:

[22] The method according to

[21] , wherein the symmetry of the metal-organic framework is changed upon removal of the residual ligand, metal salt, solvent, or any combination thereof.

[23] The plurality of metal clusters defines a plurality of metal centers, and the method further comprises: exchanging at least a portion of the first metal constituting the plurality of metal centers with a second metal; The method according to any one of the above

[15] to

[22] , comprising:

[24] The method according to

[23] , wherein the first metal is zinc and the second metal includes at least one of cobalt, nickel, or manganese.

[25] The following: combining the preformed metal cluster with 4-pyrazole carboxylic acid; and The preformed metal cluster is reacted with the 4-pyrazole carboxylic acid to form an at least partially crystalline network having a plurality of internal pores defined therein and comprising a plurality of metal clusters coordinated to the 4-pyrazole carboxylate, the plurality of metal clusters being one or more M 4 forming a metal organic framework comprising an O cluster, where M is a metal; A method comprising: The method, wherein the at least partially crystalline network has an X-ray powder diffraction pattern including characteristic diffraction peaks consistent with Pa3 symmetry.

[26] The following: A mixture containing one or more chemical species A metal-organic framework comprising: One or more M 4 contacting said metal organic framework comprising a plurality of metal clusters comprising an O cluster, where M is a metal, and a plurality of multidentate organic ligands coordinated to said plurality of metal clusters to define an at least partially crystalline network having a plurality of interior pores; and absorbing at least a portion of said one or more chemical species into at least a portion of said interior pores. A method comprising: the polydentate organic ligand comprises a 4-pyrazole carboxylate; The method, wherein the at least partially crystalline network has an X-ray powder diffraction pattern including characteristic diffraction peaks at least 8.91, 9.96, 10.9 and 12.6 (all ±5%) degrees two theta (°2θ).

[27] The method according to

[26] , wherein the one or more chemical species comprises hydrogen, nitrogen, carbon dioxide, a hydrocarbon, or a mixture thereof.

[28] The following: providing a catalyst precursor comprising a reaction product of 4-pyrazole carboxylic acid and a preformed metal cluster; exposing the catalyst precursor to a reducing agent to form an activated catalyst; contacting the activated catalyst with an olefin; and hydrogenating said olefin while said olefin is in contact with said activated catalyst; A method comprising: The reaction product has an at least partially crystalline network structure having a plurality of internal pores defined therein and has M coordinated to the 4-pyrazole carboxylate. 4 A metal-organic framework comprising a plurality of metal clusters including an O cluster (M is a metal); The method, wherein the at least partially crystalline network has an X-ray powder diffraction pattern including characteristic diffraction peaks consistent with Pa3 symmetry.

[29] The method according to

[28] , wherein at least a portion of the metal clusters comprise zinc, and at least a portion of the zinc is exchanged with a catalytically active metal.

[30] The method according to

[29] , wherein the catalytically active metal comprises Ni(II).

[31] The method according to any one of

[28] to

[30] above, wherein the reducing agent contains molecular hydrogen.

Claims

1. A metal-organic framework comprising: One or more M 4 a plurality of metal clusters including an O cluster (wherein M is zinc); a plurality of multidentate organic ligands coordinated to the plurality of metal clusters to define an at least partially crystalline network having a plurality of interior pores, the multidentate organic ligands comprising 4-pyrazole carboxylate; The metal-organic framework, wherein the at least partially crystalline network has an X-ray powder diffraction pattern including characteristic diffraction peaks at least 8.91, 9.96, 10.9, and 12.6 (all ±5%) degrees two theta (°2θ).

2. 2. The metal organic framework of claim 1, wherein said at least partially crystalline network has a cubic topology.

3. 2. The metal organic framework of claim 1, wherein at least a portion of said plurality of metal clusters comprises one or more metal centers having a tetrahedral geometry.

4. 2. The metal organic framework of claim 1, wherein at least a portion of said plurality of metal clusters comprises a divalent metal selected from cobalt, nickel, and manganese.

5. The at least partially crystalline network is Zn 4 2. The metal-organic framework of claim 1, comprising an O cluster.

6. The following characteristics: The internal pores have a pore diameter in the range of 6.0 Å to 40 Å; - the internal pores have a pore volume in the range of 0.4cc / g to 0.64cc / g; The at least partially crystalline network has a thickness of 750 mm 2 / g~1300m 2 / g, The metal-organic framework according to claim 1, comprising at least one of the following:

7. the below described: combining a metal source with 4-pyrazole carboxylic acid; and The metal source is reacted with the 4-pyrazole carboxylic acid to form an at least partially crystalline network having a plurality of internal pores defined therein, the network comprising a plurality of metal clusters coordinated to a multidentate organic ligand comprising 4-pyrazole carboxylate, the plurality of metal clusters being one or more M 4 forming a metal organic framework comprising an O cluster, where M is zinc; A method for preparing the metal-organic framework according to any one of claims 1 to 6, comprising: The method, wherein the at least partially crystalline network has an X-ray powder diffraction pattern including characteristic diffraction peaks at least 8.91, 9.96, 10.9 and 12.6 (all ±5%) degrees two theta (°2θ).

8. The method of claim 7, wherein the metal source is a preformed metal cluster.

9. The method of claim 8, wherein the preformed metal cluster comprises Zn 4 O(2,2-dimethylbutanoate) 6 .

10. 8. The method of claim 7, wherein the metal-organic framework comprises at least one of residual ligands, metal salts, or solvents within at least a portion of the plurality of interior pores.

11. The plurality of metal clusters defines a plurality of metal centers, and the method further comprises: exchanging at least a portion of the first metal constituting the plurality of metal centers with a second metal; 8. The method of claim 7, comprising:

12. 12. The method of claim 11, wherein the first metal is zinc and the second metal comprises at least one of cobalt, nickel, or manganese.

13. the below described: A mixture containing one or more chemical species Contacting with the metal-organic framework according to any one of claims 1 to 6; and absorbing at least a portion of said one or more chemical species into at least a portion of said interior pores. A method comprising:

14. 14. The method of claim 13, wherein the one or more chemical species comprises hydrogen, nitrogen, carbon dioxide, a hydrocarbon, or a mixture thereof.

Images