CN102276636B - Inorganic-organic coordination polymer containing magnesium and preparation method thereof - Google Patents

Abstract

The invention relates to an inorganic-organic coordination polymer containing magnesium and a preparation method thereof. The coordination polymer has a chemical formula as follows: [Mg(pzdc)(H2O)]n, wherein pzdc<2-> is 2,3-pyrazine dicarbonate, and n is a natural number. According to the invention, the coordination polymer is prepared by using a solvothermal method, and the purity of the obtained crystal is high; in the crystal structure, a 6-coordination mode is used for each Mg<2+> so as to form an unsymmetrical octahedron configuration; based on metal Mg<2+> as a center, four pzdc<2-> and one H2O ligand are connected at the periphery of the center, wherein one pzdc<2-> provides one N1 and O2, one pzdc<2-> provides one O3, H2O provides one O4, and the four atoms are located on the equator plane; one O1 which is located on one carboxyl group and is adjacent to N2 is provided by the other two pzdc<2->, and the two atoms are located in an axial direction; and then Mg<2+> is connected with adjacent pzdc<2-> through a ligand pzdc<2->, and the coordination polymer with a three-dimensional network structure is topologized in a space.

Description

A kind of inorganic-organic coordination polymer containing magnesium and preparation method thereof

Technical field

This synthesizes the synthetic field that belongs to the alkaline-earth metal inorganic-organic coordination polymer, is specifically related to a kind of preparation and constitutional features thereof of inorganic-organic coordination polymer of alkaline including earth metal magnesium.

Background technology

Ligand polymer, claim again Inorganic-Organic Hybrid Material, that organic ligand and metal ion are by the general name in conjunction with the compound with unlimited ordered structure formed of coordinate bond, it combines the characteristics of polymer and title complex, is that crystal engineering is applied to one of supramolecular particular embodiment of coordination.Ligand polymer is because the performance of abundant topological framework and novelty is subject to extensive concern in recent years.Ligand polymer as functional materials in fields such as selective catalysis, molecular recognition, gas adsorption, ion-exchange, magneticsubstance, biological activity and hydrogen storage materials (for example: Xiao-Feng Wang; Yue-Biao Zhang; Hong Huang; Jie-Peng Zhang; et al, Crystal Growth& Design, 2008,89 (12), 4559-4563; L Jesse, C Rowsell and O M Yaghi, J.Am.Chem.Soc, 2006,128 (4), 1304-1315) presented potential application prospect.

At present, the polymkeric substance of joining that contains transition metal is widely studied, and for example, to containing main group metal (Mg ²⁺, Ca ²⁺) the research of ligand polymer also fewer.The magnesium ion of divalence and transition metal have a lot of similaritys, for example, adopt the coordination mode of hexa-coordinate, ionic radius and the hydration that can compare favourably with transition metal ion.Nearest research shows to contain the microporous coordination polymer of magnesium to CO ₂, H ₂have a large amount of storage powers (A Mallick, S Saha, P Pachfule, et al, Inorg.Chem.2011,50,1392-1401).This novel system structure not only can be enriched the synthetic chemistry theory, also will provide new thinking for the design of novel molecular base Inorganic-Organic Hybrid Material and cutting.

Before present patent application work, still not about 2,3-pyrazine dicarboxylic acid and Mg (NO ₃) ₂6H ₂o is at EtOH/H ₂in the mixed solvent of O, self-assembly forms the patent documentation of ligand polymer aspect and the report of scientific paper.

Summary of the invention

Technical problem: the purpose of this invention is to provide a kind of inorganic-organic coordination polymer containing magnesium and preparation method thereof.This polymkeric substance be orientated, perfect crystal, and the preparation method is simple, pollution-free, has potential environmental benefit.

Technical scheme: the inorganic-organic coordination polymer containing magnesium of the present invention is the ligand polymer of following chemical formula: [Mg (pzdc) (H2O)] _n, pzdc wherein ^2-be 2,3-pyrazine dicarboxylate, n is natural number.

The crystal of this ligand polymer belongs to rhombic system, the Pnma spacer, and unit cell parameters is a=11.315 (2)

b=6.2942 (13) c=10.217 (2)

v=727.6 (2)

z=8, R ₁=0.0371, wR ₂=0.1119.Its structure is based on part pzdc ^2-bridging coordination and the space packed structures that forms of the hexa-coordinate of metal ion be three-dimensional net structure.

The preparation method who contains the inorganic-organic coordination polymer of magnesium is solvent-thermal method; With part H ₂pzdc, metal-salt Mg (NO ₃) ₂6H ₂o is raw material, with EtOH/H ₂o is solvent, and adds NaOH, under 160 ℃, reacts 72h, slowly is down to room temperature, obtains the crystal of colourless inorganic-organic coordination polymer.

EtOH and H ₂the volume ratio of O is 1: 1.

Part H ₂pzdc and metal-salt Mg (NO ₃) ₂6H ₂the mol ratio of O is 1: 1.

Part H ₂the mol ratio of pzdc and NaOH is 1: 2.

Beneficial effect: ligand polymer of the present invention is easy to preparation, the solvent-thermal method that synthetic this ligand polymer adopts be conducive to grow few defect, be orientated, perfect crystal, and the preparation method is simple, pollution-free, has potential environmental benefit.

The accompanying drawing explanation

Fig. 1 is the unsymmetric structure unit figure containing the inorganic-organic coordination polymer crystalline structure of magnesium.

The Single Crystal X-ray crystallographic structural analysis of this ligand polymer crystal shows: molecular formula is [Mg (pzdc) (H ₂o)] _n.Belong to rhombic system, the Pnma spacer, unit cell parameters is a=11.315 (2)

b=6.2942 (13)

c=10.217 (2)

v=727.6 (2)

z=8, R ₁=0.0470, wR ₂=0.1390.

Fig. 2 is the 3D frame construction drawing of ligand polymer.

Fig. 3 is the infrared wave spectrogram of ligand polymer.

Embodiment

Inorganic-organic coordination polymer containing magnesium of the present invention is by 2,3-pyrazine dicarboxylic acid and Mg (NO ₃) ₂6H ₂the ligand polymer crystal that the O self-assembly forms, chemical formula is: [Mg (pzdc) (H ₂o)] _n, n is natural number.

This experiment is synthesized the ligand polymer crystal with solvent-thermal method: with 2,3-pyrazine dicarboxylic acid and Mg (NO ₃) ₂6H ₂o is raw material, with EtOH/H ₂o makes solvent, puts into the teflon-lined stainless steel cauldron after mixing, and isothermal reaction 72h under the condition of 160 ℃ reacts the complete room temperature of slowly being down to, and obtains colourless transparent crystal [Mg (the pzdc) (H of ligand polymer ₂o)] _n.In this synthetic method, the volume preferred proportion of solvent is 1: 1, and preferably temperature is 160 ℃, and the preferred reaction time is 72h, and preferably temperature fall time is 24h.

The invention discloses a kind of crystalline structure of the inorganic-organic coordination polymer containing magnesium, see accompanying drawing 1.In this crystalline structure, Mg ²⁺for hexa-coordinate, be connected with four 2 on every side, 3-pyrazine dicarboxylic acid and a H ₂the O part, form irregular octahedron.Wherein, from one 2, an O2 on the N1 of 3-pyrazine dicarboxylic acid and the carboxyl adjacent with N1, from another one 2, the O3 on 3-pyrazine dicarboxylic acid on carboxyl adjacent with N1, and H ₂o4 on O, this four each and every one atom is on equatorial plane.The bond distance is respectively, Mg (1)-O (2)=2.084 (2)

mg (1)-O (3)=2.067 (2) mg (1)-O (4)=2.077 (3)

mg (1)-N (1)=2.236 (3)

two other 2,3-pyrazine dicarboxylic acid provides respectively O1 on a carboxyl adjacent with N2, these two atoms are on axial location.Bond distance: Mg (1)-O (1)=2.0471 (16) bond angle O (1)-Mg (1)-O (1), O (1)-Mg (1)-O (3), O (1)-Mg (1)-O (4), O (1)-Mg (1)-O (2), O (3)-Mg (1)-O (4), O (3)-Mg (1)-O (2), O (4)-Mg (1)-O (2), O (1)-Mg (1)-N (1), O (2)-Mg (1)-N (1), O (3)-Mg (1)-N (1), O (4)-Mg (1)-N (1) is respectively: 173.26 (8) °, 87.06 (4) °, 88.63 (4) °, 93.19 (4) °, 95.31 (8) °, 169.72 (8) °, 94.97 (7) °, 91.90 (4) °, 74.71 (7) °, 95.01 (7) °, 169.68 (8) °.Each Mg ²⁺by part 2,3-pyrazine dicarboxylic acid and another Mg ²⁺be connected, topology becomes three-dimensional net structure to see accompanying drawing 2.

Embodiments of the present invention are not limited to subordinate embodiment, and embodiments of the invention can make the professional and technical personnel more fully understand the present invention.Synthesizing of embodiment mono-ligand polymer:

Take 0.25mmol Mg (NO ₃) ₂6H ₂o, 0.25mmol H ₂pzdc, 0.5mmol NaOH, put into the medicine weighed up the stainless steel pressure reactor of the inner liner polytetrafluoroethylene of 25mL, adds the EtOH/H of 16mL ₂o (1: 1) mixed solvent, stir, and puts into baking oven, and Temperature Setting is 160 ℃, after isothermal reaction 72h, stops heating, then allows product cooling 24h to room temperature, then through filtration, and washing, alcohol wash and drying obtain water white crystal.

Sign to title complex:

1. the mensuration of crystalline structure

Get under the microscope the crystal of suitable size, on Bruker Smart Apex II type CCD X ray single crystal diffractometer, with Mo K α (λ=0.71073 of graphite monochromatization

) radiation is light source, at room temperature collects point diffraction.Title complex is collected altogether 7108 point diffractions in ° scope of 3.60 °≤θ≤27.48 with the ω scan mode, wherein independent point diffraction is 909, and (R (int)=0.0262), the considerable measuring point of I>2 σ (I) is 876.Crystalline structure solves by direct method, reduction of data and structure elucidation work are used respectively SAINT and SHELXTL program to complete, whole non-hydrogen atom coordinates and anisotropic temperature factor are carried out to the complete matrix least-squares refinement, all hydrogen atom is determined by theoretical method of hydrotreating, and carries out the isotropy refine.Structure iron is shown in Fig. 1 and Fig. 2.The crystallographic data of ligand polymer and structural modifications data are listed in table 1.

Table 1 ligand polymer [Mg (pzdc) (H ₂o)] _ncrystallographic data and structural modifications data

^aR＝∑||F ₀|-|F _c||/∑|F ₀|； _wR(F ²)＝[∑w(F ₀ ²-F _c ²) ²/∑w(F ₀ ²) ²] ^1/2；w＝1/[σ ²(F _o ²)+(0.063?9P) ²+0.613P]，where?P＝(Max(F _o ²，0)+2F _c ²)/3for[Mg(pzdc)(H ₂O)] _n.

2. the ligand polymer infrared absorption peak is measured (Fig. 3)

Measured the infrared spectra (400-4000cm of ligand polymer by the KBr pressed disc method ^-1), its main infrared absorption peak is: 3296.5cm ^-1, 1639.9cm ^-1, 1598.7cm ^-1, 1571.5cm ^-1, 1142.4cm ^-1, 1400.5cm ^-1, 1369.7cm ^-1, 1165.4cm ^-1, 1124.1cm ^-1, 1071.2cm ^-1, 898.4cm ^-1, 849.2cm ^-1, 771.7cm ^-1.

Claims (5)

1. the inorganic-organic coordination polymer containing magnesium, is characterized in that this ligand polymer has following chemical formula: [Mg (pzdc) (H ₂o)] _n, pzdc wherein ^2-be 2,3-pyrazine dicarboxylate, n is natural number;

The crystal of this ligand polymer belongs to rhombic system, the Pnma spacer, and unit cell parameters is

$b=6.2942\left(13\right)\stackrel{\&deg;}{A},c=10.217\left(12\right)\stackrel{\&deg;}{A},V=717.6\left(2\right)\stackrel{\&deg;}{A^3},$ Z=8, R ₁=0.0371, wR ₂=0.1119; Its structure is based on part pzdc ^2-bridging coordination and the space packed structures that forms of the hexa-coordinate of metal ion be three-dimensional net structure.

2. the preparation method of the inorganic-organic coordination polymer containing magnesium as claimed in claim 1, is characterized in that the preparation method is solvent-thermal method: with part H ₂pzdc, metal-salt Mg (NO ₃) ₂6H ₂o is raw material, with EtOH/H ₂o is solvent, and adds NaOH, under 160 ℃, reacts 72h, slowly is down to room temperature, obtains the crystal of colourless inorganic-organic coordination polymer.

3. according to the preparation method of the inorganic-organic coordination polymer of magnesium claimed in claim 2, it is characterized in that EtOH and H ₂the volume ratio of O is 1:1.

4. according to the preparation method of the inorganic-organic coordination polymer of magnesium claimed in claim 2, it is characterized in that part H ₂pzdc and metal-salt Mg (NO ₃) ₂6H ₂the mol ratio of O is 1:1.

5. according to the preparation method of the inorganic-organic coordination polymer of magnesium claimed in claim 2, it is characterized in that part H ₂the mol ratio of pzdc and NaOH is 1:2.

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