一种新型3d-4f金属有机框架晶体材料的合成、结构及性质研究

采用水热合成法,以Nd Cl3·6H2O、Co Cl2·6H2O、2,2'-联吡啶-3,3'-二羧酸(H2bpdc)、氢氧化钠和水为原料合成了一种新型3d-4f金属有机框架晶体材料。该晶体呈红色棒状,经X-射线单晶衍射分析,其结构属单斜晶系,P21/n空间群,化学式为{Nd2Co(bpdc)3(OH)2(H2O)2]·(H2O)2}n。通过单一变量法确定其最佳合成条件为:n(Nd3+)∶n(Co2+)∶n(bpdc)=1∶1∶1.5,溶于5 m L去离子水,以Na OH调节溶液p H≈5,150℃恒温72 h,降温速度1℃/h。热重分析表明该材料具有良好的热稳定性,在340℃以下可以稳定存在;经循环伏安法测试,此晶体材料具有良好的电化学活性。

Synthesis,structure and properties of a new 3d-4f type metal-organic framework crystalline material

A new kind of 3d-4f type metal-organic framework has been synthesized by reaction of NdCl3·6H2O, CoCl2·6H2O, 2,2′-bipyridyl-3,3′-dicarboxylic acid (H2bpdc), NaOH and H2O under hydrothermal conditions. The products are rod-like red crystals. A single-crystal X-ray diffraction analysis shows that its chemical formula is {［Nd2Co(bpdc)3(OH)2(H2O)2]·(H2O)2}n which belongs to monoclinic crystal system and P21/n space group. The optimized synthesis conditions were found to be n(Nd3+) : n(Co2+) : n(bpdc)=1 : 1 : 1.5, 5mL H2O as the solvent, pH 5 (adjusted by NaOH), at a temperature of 150℃ for 72h and a cooling rate of 1℃/h. The TG curve shows that this coordination polymer has good thermal stability, and is stable below 340℃. Cyclic voltammetry shows that the material is electrochemically active.