两种多钼酸盐原料的合成、表征及相互转化

Synthesis,Characterization and Transformation ofTwo Polymolybdates Raw Material

为了对多酸化合物合成过程的反应机理研究提供更多的基础信息,同时扩充同多酸盐的结构指纹图谱。以合成多钼酸盐化合物的两种常见反应物TBA_(2)[Mo_(6)O_(19)]与TBA_(4)[α-Mo_(8)O_(26)]为研究对象,以Na_(2)MoO_(4)为基础原料合成两种化合物,用红外光谱(IR)对其固体结构进行了表征,用电喷雾质谱法(Electrospray Ionization Mass Spectrometry,ESI-MS)对二者的溶液行为进行了研究。结果表明,TBA_(2)[Mo_(6)O_(19)]在溶液中的存在形式为裸多阴离子,TBA_(4)[α-Mo_(8)O_(26)]在溶液中主要以降解后形成的低核钼簇的形式存在,其中{Mo_(4)}含量最高。对两种化合物相互转化关系的研究表明,TBA_(4)[α-Mo_(8)O_(26)]溶液加酸可成功转化为TBA_(2)[Mo_(6)O_(19)],温度对该转化过程无明显影响。TBA_(2)[Mo_(6)O_(19)]溶液加碱未能成功实现其转化为TBA_(4)[α-Mo_(8)O_(26)]的逆反应过程。对两种多钼酸盐的ESI-MS、IR表征,得到了两种化合物的结构指纹图谱。对两种多钼酸盐转化的研究为多酸化合物之间的相互转化补充了一条可行方案,为多酸化合物合成过程的反应机理研究提供了更丰富的基础信息。

In order to provide more basic information for the study of the reaction mechanism in the synthesis process of polyacid compounds,and to expand the structural fingerprint of the same polyoxometalate salt.In this paper,two common reactants TBA_(2)[Mo_(6)O_(19)]and TBA_(4)[α-Mo_(8)O_(26)]used for synthesis of multi molybdate compounds were synthesized,and Na_(2)MoO_(4)was used as the basic raw material according to literature methods.Their solid structures were characterized by IR,and their solution behavior was studied using ESI-MS.The results indicate that the presence of TBA_(2)[Mo_(6)O_(19)]in solution is different from that of bare polyanions,and TBA_(4)[α-Mo_(8)O_(26)]mainly exists in solution in the form of low nuclear molybdenum clusters formed after degradation,with{Mo_(4)}having the highest content.The study on the mutual conversion relationship between two compounds shows that TBA_(4)[α-Mo_(8)O_(26)]solution can be successfully converted into TBA_(2)[Mo_(6)O_(19)]by adding acid,and the temperature has no significant effect on this conversion process.The reverse process of conversion to TBA_(4)[α-Mo_(8)O_(26)]was not successfully by adding alkali to TBA_(2)[Mo_(6)O_(19)]solution.The structure fingerprints of two polymolybdates were obtained by ESI-MS and IR characterization.The research on the conversion of two kinds of polymolybdates has supplemented a feasible scheme for the mutual conversion of polyacid compounds,and provided more abundant basic information for the research on the reaction mechanism of the synthesis process of polyoxometalate compounds.