COMPOUND OR SOLVATE THEREOF WITH MESOPOROUS METAL-ORGANIC

FRAMEWORK

Technical Field The present invention relates to a compound having a solid metal-organic framework, or a solvate thereof.

Background Art

With an increase in a demand for applications such as a fuel cell or storage of hydrogen gas, a metal-organic framework (MOF) having a hydrogen adsorbing property due to a high specific surface area has been recently investigated.

The MOF is a porous material having a three dimensional network structure, which is formed by coordinate bonds between organic bridging ligands (or organic linker ligands) and metal ions or metal clusters.

As a representative method of preparing a metal-organic frame complex, a method of forming a framework through a substitution reaction of ligand ions by using metal salts as a metal source has been widely known. Specifically, in this method, zinc nitrate [Zn(NOa) ₂ ] as the metal source, and a dicarboxylic acid-based compound as the ligand are mainly used so as to prepare a MOF having a high specific surface area

(O.M. Yaghi et al. Science, 2003, vol. 300, p. 1127; WO 02/088148).

Also, an isoreticular metal-organic framework (IRMOF) having variously sized pores and specific surface areas can be prepared by using zinc as the metal source to form core zinc oxide (Zn ₄ O) and by using various kinds of ligands with carboxlic groups.

Meanwhile, a conventional MOF can selectively receive or release guest molecules or ions according to a pore size therewithin, and also can be used as a catalyst or a reactor

for a chemical reaction.

From conventional MOFs, a MOF synthesized through a hydrothermal reaction of Cr (NO ₃ ) ₃ - 9H ₂ O and terephthalic acid is known to have pores having the largest size. However, the pore size within the MOF is only about 3.4nm(G. Ferey et. al, Science, 309, 2040 (2005) ) . Therefore, pore sizes of the conventional MOFs are not various compared to a mesoporous silica or a mesoporous carbon, which has a mesopore with a diameter in a range of 2 to 50ran in accordance with IUPAC. As described above, the conventional MOFs having a pore with a size of about 3.4nm or less have a limitation in application fields, compared to a conventional mesoporous silica or a conventional mesoporous carbon. Accordingly, a demand for development of a novel MOF having a mesopore with a size of about 3.5nm or more has been increased.

Disclosure

Technical Problem The inventors of the present invention have found that when a triazine group / tricarboxylic group containing compound as an organic linker ligand is coordinated to a metal, it is possible to obtain a porous metal-organic framework compound having a larger pore size than a conventional MOF. The present invention is based on this finding.

Technical solution

In accordance with an aspect of the present invention, there is provided a compound with a metal-organic framework

(MOF) , or a solvate thereof, the MOF having at least one pore formed therein by repeating units bonded to each other in a chain-like manner, each of the repeating units including

organic ligands and metals, wherein the organic ligand is coordinated to at least two metal atoms, and each of the coordinated metal atoms is coordinated to at least one other organic ligand in a chain like manner, thereby forming a mesopore with a diameter of 3.5 to 10ran.

Also, the present invention provides an adsorbent, a catalyst or a catalyst carrier, which includes the MOF compound or the solvate thereof.

Advantageous Effects

In the present invention, metals are coordinated to a triazine group / tricarboxylic group containing compound as an organic linker ligand. Thus, a porous MOF compound can have a large pore with a diameter of about 3.5 to 10 run, and can be utilized in various fields.

Brief Description of the Drawings

FIG. 1 illustrates one Super-Tetrahedron structure from among three dimensional X-ray structures of a MOF compound according to an embodiment of the present invention, in which (1) shows the Super-Tetrahedron structure by illustrating organic linker ligands in disorder in two directions, (2) shows a TATB as an external organic linker ligand in disorder (position or direction) , (3) shows a TATB as an internal organic linker ligand in disorder (position or direction) , and (4) shows a TATB as an external/internal organic linker ligand in a plane.

FIG. 2 illustrates three dimensional X-ray structures of a pore within a MOF compound according to an embodiment of the present invention, in which (1) illustrates a piece having a pentagonal window formed by combination of 5 Super-Tetrahedron structures, (2) illustrates a piece having a hexagonal window formed by combination of 6 Super-Tetrahedron structures, (3)

illustrates an assembled structure having a Small-pore, and (4) illustrates an assembled structure having a Large-pore.

FIG. 3 shows optical microscopic photographs of compounds obtained from Examples 1 and 2. FIG. 4 illustrates graphs illustrating XRPD (X-ray powder diffraction) patterns of the compound obtained from Example 1, in which (1) illustrates a Small-angle X-ray scattering intensity pattern (SAXS) , and (2) illustrates a Wide-angle X-ray scattering intensity pattern (WAXS) . FIG. 5 illustrates a Fourier transform infrared spectrum (FT-IR) of the compound obtained from Example 1.

FIG. 6 illustrates a Proton Nuclear Magnetic Resonance Spectrum ( ¹ H-NMR) of the compound obtained from Example 1.

FIG. 7 illustrates a thermal property of the compound obtained from Example 1, in which (1) illustrates a change in temperature-weight of the compound obtained from Example 1, and (2) illustrates substitution of DMA (solvent) coordinated to a pore and a metal of the compound obtained from Example 1, and thereby a change in temperature-weight. FIG. 8 illustrates a nitrogen gas adsorbing/desorbing property of the compound obtained from Example 1.

FIG. 9 illustrates a nitrogen gas adsorbing/desorbing property of the compound obtained from Example 2.

FIG. 10 illustrates a Fourier transform infrared spectrum (FT-IR) of the compound obtained from Example 2.

FIG. 11 a thermal property of the compound obtained from Example 2.

Best Mode

Mode for Invention

Hereinafter, exemplary embodiments of the present

invention will be described with reference to the accompanying drawings.

In general, a metal-organic framework (MOF) compound is used as an adsorbent or a storage for hydrogen gas, etc. due to its adsorbing/desorbing property of gas molecules at various temperatures. Also, the MOF compound has various sized/shaped pores and channels formed therein. Accordingly, such a compound can selectively receive or release guest molecules or ions within a pore thereof, and also can be used as a catalyst or a nano-reactor for a specific chemical reaction.

Herein, a field where such MOF compound is applied varies according to its chemical and physical properties. Such chemical and physical properties may vary according to metals and organic ligands used for synthesis, and also a pore size of the MOF compound may vary according to such metals and organic ligands. In other words, the pore size of the MOF compound may be large or small according to the metal and the organic ligand used for synthesis. In preparing a MOF compound by using organic ligands and metals currently known in the art, it is more difficult to change a pore size than anticipated. Especially, it is not easy to adjust the pore size of the MOF compound to 3.5nni or more. Therefore, conventionally, a MOF compound has had a limitation in its application fields.

Meanwhile, in the present invention, a pore size within a MOF compound may be about 3.5nm or more because repeating units, each including metal ions with a large coordination number, such as a lanthanide group metal ion (ex. terbium (Tb) having a coordination number of 6 to 10) , an actinide group metal ion, or a transition metal ion having a coordination number of 6, and a compound containing a triazine group and a tricarboxylic group (which are organic ligands) are bonded to

each other in a chain-like manner. Thus, the compound according to the present invention can be used for more various fields, compared to a conventional MOF compound.

The compound according to the present invention and a solvate thereof may be represented by Formula 1.

[Formula 1]

[Ma(TATBJb]n ,

In formula 1, M represents a transition metal ion, a lanthanide group metal ion, or an actinide group metal ion. Also, each of a and b independently represents an integer greater than 0, b/a is within a range of 0.1 ≤b/a≤ 3, and preferably of 1/3 <b/a < 8/3. Herein, b/a is 2/3 provided that an oxidation number of M is +2, and is 1 provided that an oxidation number of M is +3. Also, n represents an integer of 20 to °°, preferably of 20 to 10 ¹⁰⁰ , and herein n = ∞ means continuous repetition of a repeating unit ( [M _a (TATB) _b ] ).

Specifically, a repeating unit including metals and a triazine group/tricarboxylic group containing compound (organic ligands) is bonded to another adjacent repeating unit in a chain-like manner, thereby forming a compound (a coordination polymer) with a solid porous MOF. Herein, an average diameter of a pore within the compound may be within a range of about 3.5 to lOnm, preferably of about 3.5 to 5ran. For example, 16 metals and 8 organic ligands are bonded to each other, thereby forming a Super-Tetrahedron structure (a) as shown in FIG. 1, and also, such Super- Tetrahedron structures (a) are bonded to each other in a

chain-like manner, thereby forming a MOF compound which can be represented by a structural formula [Mi ₆ (TATB) i ₆ ] _n , and has a mesopore formed therein.

More specifically, if the metal ion as used above is Tb ³⁺ , the Super-Tetrahedron structure (a) as shown in FIG. 1 may be represented by a structure formula [Tbi ₆ (TATB) ₈ ] (+24). When such Super-Tetrahedron structures (a) are bonded to each other in a chain-like manner, a MOF compound of a neutral charge may be formed. Based on crystal structure analysis of the formed MOF, as measured by X-ray, there are 64 unit structures ( [Tbi ₆ (TATB) _i6 ] ) within a cubic unit cell. Thus, the structural formula may be represented by [Tbi ₅ (TATB) i ₆ ] . However, in the case of a structural formula showing a polymeric property without association with a crystal structure, the structural formula of the MOF may be [Tbiβ (TATB) i ₆ ] _n , as represented by Formula 2 (n represents an integer of 20 to ∞, and herein, n = ∞ means continuous repetition of a repeating unit ( [Tbi ₆ (TATB) i ₆ ] )).

The Super-Tetrahedron structure (a) has TATBs (organic ligands) positioned both inside and outside thereof. Such a Super-Tetrahedron structure (a) may be formed by a coordinate bond between a TATB (organic ligands) and a metal atom in a chain-like manner, and by a coordinate bond of the coordinated metal atom to at least one other TATB in a chain-like manner. Such a Super-Tetrahedron structure (a) may be bonded again to an adjacent Super-Tetrahedron structure, thereby forming pieces (cl and c2) having certain sized polygonal windows (bl and b2) (see FIG. 2: (1) and (2)). Then, the pieces (cl and c2) having such multiple polygonal windows may be bonded to each other, and thereby form a compound with a solid porous MOF.

If 20 Super-Tetrahedron structures (a) formed by coordinate bonds of terbium (Tb) ions of +3 (metal atoms) and

TATBs (organic ligands) in a chain-like manner are bonded to each other, 12 pieces (cl) , each having a pentagonal window (bl) with a diameter of about 12.96 A, may be formed as shown in FIG. 2 (1) . Also, such pieces (cl) may be bonded to each other, thereby forming a MOF compound having an assembled structure with a pore of a size (diameter) of about 39.1 A therewithin as shown in FIG. 2 (3) .

Also, if 28 Super-Tetrahedron structures (a) formed by coordinate bonds of terbium (Tb) ions of +3 (metal atoms) and TATBs (organic ligands) in a chain-like manner are bonded to each other, a MOF compound having an assembled structure with a pore size (diameter) of about 47.1 A therewithin may be formed as shown in FIG. 2 (4) . The assembled structure may include: 12 pieces (cl) , each having a pentagonal window (bl) with a diameter of about 12.96 A as shown in FIG. 2 (1); and 4 pieces (c2) , each having a hexagonal window (b2) with a diameter of about 17.02 A as shown in FIG. 2 (2).

More specifically, a representative compound from among compounds represented by Formula 1 may be represented by Formula 2.

[Formula 2]

In Formula 2, n represents an integer of 20 to ∞. Also, the compound represented by Formula 1 may include a solvent coordinated to metal ions such as a terbium (Tb) ion of +3. Non-limiting examples of the solvent include amine solvents, such as N,N-dimethylacetamide (DMA), N, N-

dimetylformamide (DMF), N,N-diethylformamide (DEF), etc., alcohol solvents, such as methanol, ethanol, etc., water, and a combination thereof.

A representative example of such a solvate is represented by Formula 3.

[Formula 3]

[M]6(TATB)ifi(DMA)*! ] _n ,

In Formula 3, DMA represents N,N-dimethylacetamide, and n represents an integer of 20 to ∞.

Also, the compound represented by Formula 1 may capture metal clusters within a pore thereof. Such a compound capturing metal clusters within a pore can adsorb and desorb gas by a strong binding force between the metal cluster and the gas in a hysteresis manner, and thus can be utilized in very various fields.

The metal cluster is a compound formed by a bond between metal atoms, and non-limiting examples of the metal atom include Li, Na, Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Tl, Si, Ge, Sn, Pb, As, Sb, Bi, an alloy thereof, etc. Such metal clusters may have an average particle size of about 0. Iran or more, preferably of about 0.1 to 4.5nm. The compound represented by Formula 4 is an example of the compound capturing the metal cluster within the pore.

[Formula 4]

In Formula 4, n represents an integer of 20 to ∞.

As described above, the compound represented by Formula

1 or the solvate thereof has a large pore of about 3.5nm or more, and a wide surface area, and thereby can easily adsorb or store a large amount of gas or organic molecules, even at room temperature or under atmospheric pressure, compared to a conventional MOF compound. Especially, the compound of the present invention, which captures metal clusters within a pore, can adsorb or store a large amount of gas or water by a strong binding force between the metal cluster and the gas/the organic molecules. Accordingly, the compound of the present invention or the solvate thereof may be used as adsorbents. Non-limiting examples of the gas may include ammonia, carbon dioxide, carbon monoxide, hydrogen, amine, methane, oxygen, argon, nitrogen, etc.

Also, in addition to adsorbents, the compound of the present invention or the solvate thereof may be used for catalysts, catalyst carriers, sensors, isolates, desiccants, ion exchange materials, molecular sieves (separator) , materials for chromatography, selective release and absorption of a molecule, molecular recognition, nanotubes, nano reactors, etc. Especially, when the compound of the present invention captures metal clusters within a pore, the compound may be used for catalysts, molecular reactors, sensors, etc.

A compound according to an embodiment of the present invention and the solvate thereof may be prepared by a first step of dissolving a first metal precursor and a triazine

group/tricarboxylic group containing compound in a solvent; and a second step of heating the mixed solution.

1) First, there is no particular limitation in the first metal precursor that may be used in the first step, and particular examples thereof include a transition metal capable of forming a coordination compound, a lanthanide group metal, an actinide group metal, or a compound thereof. Examples of the first metal precursor include a metal selected from groups IE ~ XVI, the lanthanide group and the actinide group of the Periodic Table, or a metal compound of the metal, such as nitrate, chlorate, sulfate salt, etc. In an embodiment of the present invention, as the first metal precursor, Tb (NO ₃ ) ₃ was used.

Also, a representative example of the triazine group/tricarboxylic group containing compound is 4,4',4"-s- triazine-2, 4, 6-tribenzoic acid.

There is no particular limitation in the solvent that may be used in the present invention, as long as the solvent can uniformly dissolve the first metal precursor and the triazine group/tricarboxylic group containing compound, and non-limiting examples of the solvent include amines (such as N,N-dimethylacetamide (DMA) , N,N-dimetylformamide (DMF) , N, N- diethylformamide (DEF) , etc.), alcohols (such as methanol, ethanol, etc.), water and a mixture thereof. Especially, when N,N-dimethylacetamide, methanol, and water are mixed, the volume ratio thereof may be 1~5 : 0.1~2 : 0.1~2.

Herein, the first metal precursor (a) and the triazine group/tricarboxylic group containing compound (b) may be mixed in a molar ratio of 0.1 < b/a ≤ 10. If the mixing ratio is out of the above range, components for forming a MOF are highly insufficient. Thus, it is impossible to obtain a high-quality uniform crystal because the growth of crystal seeds randomly formed on spots of a reaction vessel is not appropriately

carried out.

2) Then, when the mixed solution is heated at a predetermined temperature, the first metal precursor is coordinated to the triazine group/tricarboxylic group containing compound, thereby forming the compound represented by Formula 1 or the solvate thereof.

Herein, the heating temperature of the mixed solution is preferably within a range of about 60 to 180 ^° C. If the heating temperature is lower than 60 ^° C, the degree of crystallinity may be increased, but the crystal forming speed may be too low. If the heating temperature is higher than 180 ^° C, the degree of crystallinity may be decreased, the crystal size may become too small, and an amorphous material may be synthesized. Meanwhile, the present invention may provide a compound including a compound prepared by the above described method; and metal clusters captured within the pore of the compound.

The compound capturing metal clusters within a pore thereof may be prepared by 1) a first step of immersing the compound represented by Formula 1, prepared by the above described method, or the solvate thereof, into a material selected from the group including dichloromethane, acetonitrile, tetrahydrofuran, methanol, ethanol, toluene, trichloromethane and a mixture thereof, and drying the immersed compound; and 2) a second step of immersing the compound obtained from the first step in a solution of a second metal precursor dissolved in ethylene glycol, thereby forming a mixed solution; and 3) a third step of heat-treating the mixed solution obtained from the second step. 1) The dichloromethane, acetonitrile, tetrahydrofuran, methanol, ethanol, toluene, trichloromethane, etc. used in the first step, into which the compound represented by Formula 1 or the solvate thereof is immersed, can facilitate the

penetration of the second metal precursor dissolved in ethylene glycol and also contribute to reduction of a metal and stabilization of metal nanoparticles. These materials may be used alone or in combination. 2) The metal cluster captured within the pore is obtained from the second metal precursor, and non-limiting examples of the second metal precursor include K ₂ PtCl ₄ , K ₂ PdCl ₄ , H ₂ PtCl ₆ , KAuCl ₄ , AgNO ₃ , etc.

3) The heat-treatment in the third step is for growing the metal cluster within the pore of the compound used in the first step. Such heat-treatment may be carried out at about 100 to 200 ^° C for 1 to 3 hours, preferably, at about 130 to 140 ^° C for about 2 hours. If the mixed solution is left at room temperature, the growing speed of reduced metal nanoparticles may be too slow. Herein, the heat-treatment is preferably carried out in a state where the mixed solution obtained from the second step is sealed.

Reference will now be made in detail to the preferred embodiments of the present invention. However, the following examples are illustrative only, and the scope of the present invention is not limited thereto.

Example 1 Tb(NO ₃ ) ₃ -5H ₂ O(0.030 g, 6.90><10 ^~5 mol) and 4,4',4"-s- triazine-2,4, 6-tribenzoic acid (H ₃ TATB) (0.010 g, 2.27 ^χ lO ^"5 mol) were dissolved in N, N' -dimethylacetamide

(DMA) /methanol/water (2.0/0.4/0.1 ml). The mixed solution was poured in a 20 ml vessel and heated in a sealed state in an oven at about 105 ^° C for 2 days, to obtain a colorless truncated octahedral shaped solid crystal (hereinafter, referred to as ^λ TbTATB' ) . The obtained solid crystal is a compound represented by Formula 5. FIG. 3 (1) is an optical

microscopic photograph of the obtained solid crystal. The yield of the obtained solid crystal was about 44.6% per 1.0 mol of H ₃ TATB, and based on the three dimensional X-ray structure of the solid crystal, the solid crystal includes a pore with a diameter of 39.1 A, and a pore with a diameter of 47.1 A (see FIG. 2: (3) and (4)). Herein, the diameter of a pore within the prepared solid crystal was measured by using a program Accelrys Materials Studio 4.3, and the method is as follows.

A virtual sphere whose origin is the center of a pore was generated, and the diameter of the sphere was adjusted so that the sphere can fully occupy the pore. Two TATBs on the inner wall of a pore firstly closed to the surface of the sphere were checked, and a coordinate corresponding to the center of a triazine ring positioned in the center of each TATB was generated. Then, the distance between the centers of the two TATBs was measured. Finally, the diameter of a pore that may be used as a vessel was determined by, from the distance, subtracting 3.4 A equal to two times of the van der Waals radius of a carbon atom (1.7 A).

[Formula 5]

[Tbi6<TATB)i ₆ (DMA)24]n ,

(In Formula 5, DMA represents N,N-dimethylacetamide, and n represents an integer of 20 to ∞)

Experimental Example 1 - Determination of crystallinity

In order to determine the crystallinity of the compound (represented by Formula 5) obtained from Example 1, the result

measured by X-ray powder diffractometry (XRD) was plotted together with a simulation pattern in FIG. 4.

As a result of the experiment, it can be seen from FIG. 4 (2) showing Wide-angle X-ray scattering intensity pattern (WAXS) , in which the crystalline peaks observed at the same positions as those of the simulation pattern, that the compound obtained from Example 1 is a crystalline material and has a pure crystal excluding impurities.

Also, as shown in FIG. 4 (1) showing Small-angle X-ray scattering intensity pattern (SAXS) , the peaks observed at the same positions as those of the simulation pattern, and most peaks observed at 2θ value of less than 5 degrees. Thus, since the peak position, that is, 2θ value, is in inverse proportion to the size of a unit cell (a Bragg' s law), it can be seen that the compound obtained from Example 1 has a cubic unit cell having each side of 123.9 A. Accordingly, it is determined that the compound according to the present invention is a crystalline material with a large sized crystal .

Experimental Example 2 - Analysis of a chemical structure

In order to determine the chemical structure of the compound obtained from Example 1, Fourier transform infrared Spectroscopy (FT-IR) and Proton Nuclear Magnetic Resonance Spectroscopy ( ¹ H-NMR) were carried out.

2-1. FT-IR measurement

The chemical structure of the compound obtained from Example 1 was directly measured by using an FT-IR spectrometer, and not by forming the compound into a KBr pellet. The FT-IR spectrum was plotted in FIG. 5.

It can be seen from the above experimental results that

in the case of the compound obtained from Example 1, peaks observed at 3423 (br), 2927 (w) , 2365 (w) , 1625 (s, DMA C=O), 1539 (s), 1503 (s, nas COO ^" ), 1415 (s) , 1395 (vs) , 1353 (vs, ns COO ^" ), 1263 (m) , 1186 (m) , 1059 (w) , 1014 (s) , 883 (w) , 864 (w), 829 (m) , 801 (w) , 776 (vs) , 749 (w) , 699 (w) , and 653 (w) (see FIG. 5) . Especially, it is known in the art that peaks corresponding to stretching vibrations of C=O and C-O of carboxylic acid (C00 ^~ ) usually occur at 1720 to 1690cm ^"1 and 1320 to 1210cm ^"1 , respectively, while peaks of carboxylic acid (COO ^" ) in the TATB (organic ligand) of the compound obtained from Example 1 observed at 1503 cm ^"1 and 1353 cm ^'1 . Based on the difference of peaks, it is determined that carboxylic acid (COO ^" ) of the TATB (organic ligand) is bonded to metals. Also, it is known in the art that a C=O peak of DMA (solvent) occurs at 1637 cm ^"1 , while a C=O peak of DMA in the compound obtained from Example 1 was slightly shifted to 1625 cm ^"1 . It is assumed that such a shift was caused by the coordination of the DMA to the metal .

2-2. ¹ H-NMR measurement

The compound obtained from Example 1 was dissolved in descarbonylethoxyloratadine (DCL) and dimethyl sulfoxide (DMSO), and ¹ H-NMR(SOO MHz) was measured. The measured result was plotted in FIG. 6. According to the experimental result, in the compound obtained from Example 1, peaks observed at 8.75 p. p.m. (d, 6H), 8.15 (d, 6H), 2.8 (s, ~22H) , 2.75 (s, -22H), and 1.8 (s, ~22H) (see FIG. 6) . Based on the ratio analysis of the number of protons disposed in the NMR peak, it can be seen that 7.2 DMAs exist per one TATB (ligand) . Accordingly, it is determined that each repeating unit [Mi ₆ (TATB) ₁₆ (DMA) ₂₄ ] includes, in addition to 24 DMAs coordinated to metals, 91 other DMAs uncoordinated to the metal and existing within a

pore thereof.

Experimental Example 3 - Measurement on a thermal property In order to measure the thermal property of the compound obtained from Example 1, the following experiment was carried out .

1) First, Thermogravimetric Analysis (TGA) was carried out (described below) , and the experimental result was plotted in FIG. 7(1) .

About 12mg of the compound obtained from Example 1 was heated from about 25 ^° C to 700 ^° C at a rate of about 5 ^° C/minute.

As a result of the experiment, as shown in FIG. 7(1), the weight of the compound obtained from Example 1 was decreased stepwise by three steps. First, in the first step with a heating temperature ranging from about 25 to 120 ^° C, the extent of decreased weight was about 47.2%. It is assumed that the decrease of weight was caused by the removal of 91 DMAs and 108 H ₂ Os existing within the pore. Also, in the second step with a heating temperature ranging from about 120 to

320 ^° C, the extent of decreased weight was about 9.2%. It is assumed that the decrease of weight in this step happened because coordinate bonds of 24 DMAs which had been coordinated to the metal were cleaved and the DMAs were pyrolyzed. Also, in the third step with a heating temperature ranging from about 320 to 500 ^° C, the extent of decreased weight was about 29.7%. It is assumed that the decrease of weight happened because the TATB (ligand) was pyrolyzed. After such pyrolysis, the weight of an unpyrolyzed residual product was about 13.9%, and herein, the residual product was metal oxide.

According to the experimental result, the TATB (ligand) of the compound obtained from Example 1 was not pyrolyzed until about 320 ^° C. It can be seen from the result that the

compound obtained from Example 1 is thermally stable until at least about 320 ^° C. It is assumed that this is because the compound obtained from Example 1 has a solid MOF.

2) In order to determine whether the DMA (solvent) existing within the pore of the compound obtained from Example 1, and the DMA (solvent) coordinated to the metal were substituted or not, pyrolysis properties after the substitution were measured as follows, and the measured results was plotted in FIG. 7(2). A test sample 1 was obtained by immersing the compound obtained from Example 1 into trichloromethane (CHCl ₃ ) , and a test sample 2 was obtained by immersing the compound obtained from Example 1 into water (H ₂ O) . Also, as a control group of the samples, the compound obtained from Example 1 was used. These materials were heated from 25 ^° C to 700 "C at a rate of about 5 ^° C/minute.

As a result of the experiment, in the case of the control group, the weight was gradually decreased at about 25 to 120 °C . On the other hand, in the case of the test samples 1 and 2, the weight was suddenly decreased at about 25 to 50 ^° C. Based on the difference in the pyrolysis, it is determined that the test sample 1 had trichloromethane within a pore thereof, and that test sample 2 had water within a pore thereof, unlike the control group, which had the DMA (solvent) within a pore thereof. Accordingly, it is assumed that the DMA (solvent) existing within the pore of the compound obtained from Example 1 can be easily substituted by trichloromethane or water.

Meanwhile, in the temperature range of about 120 to 320 ^° C, in which the DMA (solvent) coordinated to the metal is assumed to be pyrolyzed, the control group and the test sample 1 showed similar pyrolysis patterns. Accordingly, it is determined that the DMA (solvent) coordinated to the metal is

not easily substituted by trichloromethane. On the other hand, in the above mentioned temperature range, the pyrolysis of the test sample 2 was different from that of the control group. Accordingly, it is determined that the DMA (solvent) coordinated to the metal is easily substituted by water.

Experimental Example 4 - Measurement on gas adsorbing property and surface area

In order to measure the gas adsorbing/desorbing property and surface area of the compound obtained from Example 1, the following pre-treatment was carried out, and then a nitrogen adsorbing test was carried out by using automatic adsorption instrument at 77K. The test results were plotted in FIG. 8, and Table 1 shows the surface area calculated by using BET and Langmuir Theory.

The pre-treatment was carried out by immersing the compound obtained from Example 1 into H ₂ O for 10 minutes, and then heating the compound under vacuum (1.0 ^χ l0 ^~3 Torr or less) at 80 ^° C and then at 160 ^° C for 12 hours, respectively, thereby removing the DMA existing within the pore.

Table 1

As shown in FIG. 8, it can be seen from the above experimental results that the compound obtained from Example 1 can reversibly adsorb/desorb nitrogen gas.

Also, as noted in Table 1, the surface area of the

compound pre-treated at 160 ^° C was more significantly increased than that of the compound pre-treated at 80 ^° C, which is because the DMA coordinated to the metal was more significantly removed during the pre-treatment at high temperature than at low temperature, resulting in a decrease of weight of a MOF and a relative increase of volume of a pore capable of containing nitrogen gas.

Example 2 0.03Og of the solid crystal obtained from Example 1 was immersed into trichloromethane (CHCl ₃ ) for 3 hours, and was dried in the air to remove unbonded residual trichloromethane. Then, the dried compound was added in a solution of 367mg of Potassium tetrachloroplatinate ( II ) dissolved in 20ml of ethylene glycol. The mixed solution was stored at about 130 to 140 ^° C for 2 hours in a sealed state. As a result, a solid crystal capturing black metal clusters within a pore with a diameter of about 39.1 A and within a pore with a diameter of about 47.1 A (hereinafter, referred to as a ^λ metal cluster capturing TbTATB' ) was finally obtained, and the obtained solid crystal was a compound represented by Formula 6. The microscopic photograph of the obtained solid crystal is shown in FIG. 3 (2) , in which the color of the solid crystal is darker than that of the solid crystal obtained from Example 1, shown in FIG. 3 (1) . Based on the change of the solid crystal color, it can be indirectly seen that the solid crystal obtained from Example 2 has a metal cluster introduced therein.

[Formula 6]

ITbiβ(TATB)t6]n-Pt3n ,

I In Formula 6, n represents an integer of 20 to

Experimental Example 5 - Measurement on gas adsorbing property and surface area

In order to measure the gas adsorbing/desorbing property and surface area of the compound obtained from Example 2, the following pre-treatment was carried out, and then a nitrogen adsorbing test was carried out by using automatic adsorption instrument at 77K.

The pre-treatment was carried out by immersing the compound obtained from Example 2 into H ₂ O for 10 minutes, and then heating the compound under vacuum (1. OxICT ³ Torr or less) at 160 ^° C for 12 hours. The test results were plotted in FIG. 9, and Table 2 shows the surface area calculated by using BET.

Table 2

As a result of the test, as shown in FIG. 9, the compound obtained from Example 2 adsorbed and desorbed nitrogen gas in a hysteresis manner at about 550 to 760 Torr, which is because adsorbed nitrogen gas is not easily desorbed due to a strong binding force between the metal cluster and the nitrogen gas within a pore. Also, the BET surface area of the compound obtained from Example 2 is about 691 mVg as noted in Table 2, which is

smaller than that of the solvate of Example 1 (that is, about

1783m7g) (see Tables 1 and 2) . The reason the BET surface area of the compound from Example 2 is smaller than that of the solvate from Example 1 is assumed that the volume of the pore is decreased due to the metal cluster included within the pore.

Experimental Example 6 - Analysis of chemical structure

In order to determine the chemical structure of the compound obtained from Example 2, Fourier transform infrared Spectroscopy (FT-IR) was carried out.

The chemical structure of the compound obtained from Example 2 as a test sample 3 was directly measured by using an FT-IR spectrometer, not by forming the compound into a KBr pellet. As a control group 1, the compound obtained from Example I ₁ which was heated in Thermogravimetric Analysis (TGA) up to about 250 ^" C, was used. The FT-IR spectrum of these compounds was plotted in FIG. 10.

As a result of analysis on FT-IR spectrum of the test sample 3, in the test sample 3, peaks observed at 1506 (s, nas COO ^" ), 1419 (m) , 1395 (s) , 1351 (vs, ns COO ^" ), 1016 (m) , 881 (w) , 827 (m) , 770 (s) , 699 (w) , and 667 (m) , which is similar to FT-IR spectrum of the control group 1. It can be seen from the above experimental results that the structure of a compound capturing metal clusters within a pore thereof is similar to that of a compound including DMA (solvent) within a pore thereof.

Experimental Example 7 - Measurement on a thermal property

In order to measure the thermal property of the compound obtained from Example 2, the following Thermogravimetric Analysis (TGA) was carried out, and the measured results were

plotted in FIG. 11.

About 12mg of the compound obtained from Example 2 was heated from 25 ^° C to 700 ^° C at a rate of about 5 ^° C/minute.

As shown in FIG. 11, the weight of the compound obtained from Example 2 was gradually decreased during elevation of the temperature up to about 300 ^° C, rapidly decreased during elevation of the temperature up to about 380 ^° C, and then was not decreased any more. Herein, it is assumed that the weight decrease of total about 68% was caused by pyrolysis of 16 TATBs (ligand) , and the residual ratio of about 32% was caused by residual materials without being pyrolyzed, such as 16 Tbs and 16 platinum (Pt) oxides.

It can be seen from the above experimental results that a compound capturing a metal cluster within a pore thereof is thermally stable up to at least about 300 ^° C, and it is assumed that this is because the compound has a solid MOF.