Co(Ⅱ)与烟酸类分子形成的配位聚合物的晶体结构与孔道稳定性

Crystal Structures and Pore Stability of Coordination Polymers Constructed by Nicotinic Acid and Isonicotinic Acid with Co(Ⅱ)

利用烟酸与异烟酸两种配体分别与硝酸钴在N,N-二甲基甲酰胺(DMF)中采用溶剂热法合成了三种新的配位聚合物[Co2(μ2-H2O)(nicotinic acid)4·(DMF)](1),[Co2(isonicotinic acid)4·(DMF)](2),[Co(isonicotinic acid)2·(DMF)](3),并利用单晶X射线衍射(XRD)和元素分析获得其结构信息.通过傅里叶变换红外(FTIR)光谱、粉末X射线衍射(XRD)、热重分析(TGA)和比表面积分析等手段对结构中孔道的热稳定性进行了表征.结果表明化合物1具有类金刚石的拓扑结构,结构中含有稳定的一维(1D)孔道空间.化合物2和3是以异烟酸为配体,分别在100和160°C下合成,二者结构中配体以完全不同的方式与Co(II)配位,从而使其具有不同的结构.化合物2和3的一维孔道在热处理脱附DMF分子的过程中不能稳定存在.

icotinic acid and isonicotinic acid were utilized to react with Co（NO3）2 in N,N＇- dimethylformamide （DMF） in solvothermal conditions respectively, and resulted in three new coordination polymers： [Co2（μ2-H2O）（nicotinic acid）4·（DMF）] （1）, [Co2（isonicotinic acid）4·（DMF）] （2）, and [Co（isonicotinic acid）2·（DMF）] （3）. Single crystal X-ray diffraction （XRD） and elemental analysis were performed to obtain structural information on these compounds. Fourier transform infrared （FTIR） spectroscopy, thermogravimetric analysis （TGA）, and N2 isotherm analysis were utilized to investigate the pore stability of the three compounds. The above experiments reveal that compound 1 has a diamond-like topology, and the one-dimensional （1D） channels in compound 1 are stable after the removal of DMF molecules. Compounds 2 and 3 were synthesized at 100 and 160 °C by the coordination of isonicotinic acid with Co（II）, respectively. The coordination modes of isonicotinic acid to Co（II） are completely different in the two compounds, which lead to two different crystal structures. The 1D channels in compounds 2 and 3 were not stable after the removal of DMF molecules.