基于[P_2W_(15)O_(56)]~(12-)构筑块的四核铜夹心型化合物的合成、结构表征及其热稳定性

以三缺位型Dawson结构的钨磷酸盐前驱体Na12α-P2W15O56]·24H2O与CuCl2·6H2O和Na3PO4为原料、水为溶剂,经溶液合成法合成了四核夹心型多金属氧酸盐化合物Na3H13Cu4(H2O)2(P2W15O56)2]·72H2O(1);利用X射线单晶衍射仪、红外光谱仪、紫外光谱仪、X射线粉末衍射仪等分析了合成产物的结构,采用变温红外光谱测定了其热性质.结果表明,该化合物为三斜晶系,P-1空间群;其晶胞参数为:a=1.318 1(2)nm,b=1.345 1(2)nm,c=2.497 3(4)nm,α=78.149(3)°,β=88.242(3)°,γ=62.087(2)°.该化合物的骨架结构由两个三缺位的Dawson结构单元{P2W15O56}通过一个{Cu4O16}簇连接而成;其在350℃以下表现出一定的热稳定性.

Synthesis of tetracopper sandwiched polyoxotungstate based on [P2W15O56]12-unit,structure characterization and its thermal stability

A tetranuclear sandwich-type polyoxometalate（coded as POM）,Na3H13 Cu4（H2O）2（P2W15O56）2]·72H2O（1）,was synthesized viathe aqueous solution reaction of trivacant Dawson precursor Na12α-P2W15O56]·24H2O plus CuCl2·6H2O and sodium phosphate as the starting materials.As-synthesized compound was characterized by X-ray single crystal diffraction,infrared spectrometry,ultraviolet spectrometry and X-ray powder diffraction,while its thermal stability was examined by varied temperature infrared spectrometry.Results indicate that as-synthesized compound1 crystallizes in the triclinic P-1space group,and it exhibits crystal cell constants of a =1.318 1（2）nm,b =1.345 1（2）nm,c =2.497 3（4）nm,α =78.149（3）°,β=88.242（3）°,γ =62.087（2）°.Besides,the polyanion backbone of compound1 consists of one{Cu4O16}cluster sandwiched by two trivacant Dawson-type{P2W15O56}building units;and compound 1is basically thermally stable below 350℃.