JP2008184533A - Coordinate polymer metal complex compound single crystal and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coordinate polymer metal complex compound single crystal having increased gas adsorptivity and a method for producing the compound. <P>SOLUTION: The coordinate polymer metal complex compound single crystal is a porous bulk single crystal of a coordinate polymer metal complex compound having a composition having as a skeleton a coordinate polymer metal complex having a three-dimensional structure expressed by [M<SB>2</SB>(C<SB>6</SB>H<SB>2</SB>N<SB>2</SB>O<SB>4</SB>)<SB>2</SB>(C<SB>4</SB>H<SB>4</SB>N<SB>2</SB>)]4H<SB>2</SB>O as one unit, wherein M is a pentadentate metal element selected from Cu, Ni and Cd, in which complex the two-dimensional structures composed of the metal element M and 2,3-pyrazine dicarboxylate are bonded together through a column composed of pyrazine interposing a gap between the structures, and the gap is divided with the column to form pores. Water is supplied on an aqueous solution A of the pentadentate metal element salt and pyrazine to form a water layer, an aqueous solution B of 2,3-pyrazine dicarboxylic acid is supplied on the water layer at a supplying rate of 0.04-0.4 cm<SP>3</SP>/sec to form a layer of an aqueous solution B and the product is left to stand at room temperature. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a single crystal coordination polymer metal complex compound excellent in gas adsorption and a method for producing the same.

Conventionally, as a coordination polymer metal complex compound having gas adsorbability, Non-Patent Document 1 discloses that 1 unit is [Cu ₂ (C ₆ H ₂ N ₂ O ₄ ) ₂ (C ₄ H ₄ N ₂ )] · 2H. _It has a composition represented by ₂ O, and has a three-dimensional structure in which the two-dimensional structure composed of the Cu element and pyrazine-2,3-dicarboxylate is connected to each other with a pillar composed of pyrazine with a gap therebetween. A coordination polymer metal complex compound having pores in which the coordination polymer metal complex is a skeleton and the gap is divided by the support columns is shown. However, this compound has been successfully synthesized only as a powder so far, and has not been synthesized as a bulk single crystal having high gas adsorbability.

In Patent Document 1, as a proton exchange membrane of a solid polymer fuel cell, water molecules are occluded between layers of coordination polymer metal complex R ₂ dtoaM (R: alkyl group, dtoa: dithiooxamide), and proton conduction is performed at room temperature. Compounds having properties are disclosed. Further, Patent Document 2 shows that the above-described complex is made to absorb hydrogen and to have electron conductivity at room temperature. However, in any case, no consideration is given to gas adsorption.

Mitsuru Kondo et al., Angew.Chem.Int.Ed. 1999, 38, No. 1/2, pp. 140-143 JP 2004-31173 A JP 2004-31174 A

  An object of the present invention is to provide a single crystal coordination polymer metal complex compound with improved gas adsorption and a method for producing the same.

In order to achieve the above object, according to the first invention, a composition in which one unit is represented by [M ₂ (C ₆ H ₂ N ₂ O ₄ ) ₂ (C ₄ H ₄ N ₂ )] · 4H ₂ O And M is a pentacoordinate metal element selected from Cu, Ni, and Cd, and a two-dimensional structure composed of the metal element M and 2,3-pyrazine dicarboxylate is composed of pyrazine. A coordination polymer metal complex compound having pores in which the coordination polymer metal complex having a three-dimensional structure connected with a gap between each other has a skeleton, and the gap is divided by the support, Provided is a single crystal coordination polymer metal complex compound characterized by constituting a bulk single crystal.

Furthermore, according to the second invention, there is provided a method for producing a single crystal coordination polymer metal complex compound of the first invention, comprising:
Producing an aqueous solution A of the pentacoordinate metal element salt and pyrazine;
Supplying water onto the aqueous solution A to form a layer of the water on the solution A;
Supplying a 2,3-pyrazinedicarboxylic acid aqueous solution B onto the water layer at a supply rate of 0.04 to 0.4 cm ³ / second to form a layer of the aqueous solution B on the water layer; and thereafter , Leaving at room temperature to obtain the bulk single crystal,
A method for producing a single crystal coordination polymer metal complex compound is provided, which comprises performing a multi-layer method including:

  Since the single crystal coordination polymer metal complex compound of the first invention is a bulk single crystal, the space in the pores of the coordination polymer metal complex compound can be fully utilized as a gas adsorption site. Compared with powder, gas adsorption performance is greatly improved.

  The method for producing a single crystal coordination polymer metal complex compound of the second invention is to grow a coordination polymer metal complex compound as a bulk single crystal by using a multilayer method and controlling the supply rate of the reaction solution. Can do.

  In the present invention, the term “bulk single crystal” refers to one in which a whole solid block or granule consists of a single crystal. On the other hand, “powder” refers to powder particles each composed of a plurality of crystals (secondary particles in which a plurality of primary particles, which are single crystals, are irregularly combined into a polycrystal).

  Since the coordination polymer metal complex compound of the present invention is a single crystal, that is, one whole is a single crystal, the pores constituting the crystal are regularly aligned and the elongated pores extend over the entire length. It penetrates without blocking on the way. For this reason, the pores present in one individual function as an adsorption site extremely efficiently, so that high gas adsorbability can be exhibited.

  Since the conventional coordination polymer metal complex compound is a powder, that is, an individual is an aggregate of a plurality of crystals, the frequency of the pores of each crystal being blocked at the interface with an adjacent crystal in one individual is high. Therefore, since the number and volume of pores present in one individual that function as effective adsorption sites are small, high gas adsorbability cannot be exhibited.

The method for producing a single crystal coordination polymer metal complex compound of the present invention can grow a bulk single crystal stably by using a multilayer method and limiting the supply rate of the reaction solution within an appropriate range. it can. That is, the supply rate of the aqueous solution of 2,3-pyrazinedicarboxylic acid B onto the water layer formed on the aqueous solution A of the 5-coordinate metal element salt and pyrazine is set to 0.04 to 0.4 cm ³ / sec. Restrict.

When the supply rate of the aqueous solution B is less than 0.04 cm ³ / second, impurity crystals other than the original crystals are mixed. For example, when Cu is used as a five-coordinate metal element, a product in which green grains are mixed in addition to the original blue crystal is formed. This is presumed to be because Cu ions to be bonded to the pyrazine support are bonded to other portions.

On the other hand, when the supply rate of the aqueous solution B exceeds 0.4 cm ³ / sec, the interface between the liquid layers is disturbed and an appropriate multi-layer method cannot be performed.

  According to the present invention, a single crystal coordination polymer metal complex compound was synthesized by using a multilayer method. Cu was used as a pentacoordinate metal element. The synthesis conditions and procedures were as follows. FIG. 1 (1) schematically shows the apparatus used. In this structure, the reaction solution is dropped into the reaction vessel by a dropping device. FIG. 1 (2) shows a three-layer structure formed by a multilayer method.

(1) In the reaction vessel shown in FIG. 1, copper (II) perchlorate hexahydrate and pyrazine are dissolved in 300 cm ³ of water to obtain a blue aqueous solution A. That is, the first layer shown in FIG. 1 (2) is formed.

(2) Overlaying 300 cm ³ of water on the aqueous solution A at a dropping rate of 0.08 cm ³ / sec by the multi-layer method, a colorless water layer is formed on the blue aqueous solution. That is, the second layer shown in FIG. 1 (2) is formed.

  (3) Furthermore, a 2,3-pyrazinedicarboxylic acid aqueous solution (colorless) is stacked on the water layer to form a three-layer stacked state. That is, the third layer shown in FIG. 1 (2) is formed.

  (4) Leave in this state at room temperature for 1 day to obtain blue crystals. A micrograph is shown in FIG. Five rod-like single crystals are observed in the visual field.

  As a result of single crystal X-ray structural analysis of the obtained blue crystal, it was found that the two-dimensional structure formed by copper and 2,3-pyrazine dicarboxylate was linked by pyrazine to form a porous material. .

  Next, as a conventional example, the same solution A and solution B as described above were directly mixed and stirred. This produced a blue powder. A micrograph is shown in FIG. Innumerable fine particles are in an aggregated state.

  In the present invention, by using the multi-layer method, water as a reaction solvent is interposed between the two reaction solutions A and B, so that the diffusion of the reactants between the reaction solutions A / B is slowed and coordinated. It is considered that the polymer metal complex compound is slowly formed, and as a result, the reaction product grows into a single crystal.

  On the other hand, in the conventional method, since the two reaction solutions A and B are directly mixed and stirred, a coordination polymer metal complex compound is instantaneously generated. In such a high-speed reaction, the reaction product cannot grow into a single crystal, but becomes a powder composed of polycrystalline fine particles.

  The adsorption amount of hydrogen was measured under the following conditions for the single crystal sample obtained by the multilayer method according to the present invention and the powder sample obtained by the conventional direct mixing method.

<Hydrogen adsorption test conditions>
Measuring device: PCT evaluation device Measuring method: flow method Measuring pressure: 20 MPa, 30 MPa (2 levels)
Measurement temperature: room temperature The measurement results are shown in FIG. The hydrogen gas adsorption amount at the measurement pressures of 20 MPa and 30 MPa was 0.08 mass% and 0.15 mass% for the powder sample of the conventional example, whereas 0.13 mass% and 0 for the single crystal sample of the present invention example. It can be seen that the mass is significantly improved to 21 mass%.

  ADVANTAGE OF THE INVENTION According to this invention, the single crystal coordination polymer metal complex compound which improved gas adsorbability, and its manufacturing method are provided.

It is a schematic diagram which shows (1) arrangement | positioning of an apparatus for synthesize | combining the single crystal coordination polymer Cu complex compound of this invention by a multilayer method, and (2) the liquid layer structure in reaction container. 1 is a photomicrograph of a single crystal coordination polymer Cu complex compound synthesized by the multilayer method of the present invention and (2) a powdery coordination polymer Cu complex compound synthesized by a conventional direct mixing method. It is a graph which shows the relationship between hydrogen gas adsorption amount and measurement pressure about (1) single crystal coordination polymer metal complex compound of this invention and (2) conventional powdery coordination polymer metal complex compound.

Claims (2)

One unit has a composition represented by [M ₂ (C ₆ H ₂ N ₂ O ₄ ) ₂ (C ₄ H ₄ N ₂ )] · 4H ₂ O, and the M is selected from Cu, Ni, and Cd It is a five-coordinate metal element, and has a three-dimensional structure in which two-dimensional structures composed of the metal element M and 2,3-pyrazine dicarboxylate are connected to each other with pillars made of pyrazine and spaced from each other. A coordination polymer metal complex compound having a pore composed of a coordination polymer metal complex as a skeleton, and the gaps separated by the support columns, and constituting a bulk single crystal Coordination polymer metal complex compound. A method for producing a single crystal coordination polymer metal complex compound according to claim 1,
Producing an aqueous solution A of the pentacoordinate metal element salt and pyrazine;
Supplying water onto the aqueous solution A to form a layer of the water on the solution A;
Supplying a 2,3-pyrazinedicarboxylic acid aqueous solution B onto the water layer at a supply rate of 0.04 to 0.4 cm ³ / second to form a layer of the aqueous solution B on the water layer; and thereafter A method for producing a single crystal coordination polymer metal complex compound, comprising a step of standing at room temperature and performing a multilayer method including a step of obtaining the bulk single crystal.