~(51)V NMR监测[VS_4Cu_n](n≤6)簇合物自兜反应过程

采用　51VNMR监测在核磁管内模拟 (NH4 ) 3VS4 /Et4 NBr/CuBr/PPh3体系在CH2 Cl2 中的反应过程 ,研究了反应条件如反应物不同配比对生成各种 [VS4 Cun](n≤ 6)簇合物的影响 ,提供了该反应体系在CH2 Cl2 溶液中成簇过程的一些信息 .该方法不仅可用来研究反应机理 ,而且可用于指导一些条件难以确定 (溶剂、温度、酸碱度等 )的簇合物如低核数及更高核数V Cu S簇合物的合

~(51)V NMR STUDIES ON THE REACTION OF [VS_4-Cu_n] (n=3-6) CLUSTERS

在核磁管内模拟反应体系 (NH4)3VS4/Et4NBr/CuBr/PPh3在CH2 Cl2 溶液中生成[VS4 Cun](n =3 6 )簇合物的过程 .利用 51 VNMR技术对反应过程进行准原位的实时监测 ,研究 [VS4 Cun](n =3 6 )簇合物的成簇条件和机理以及配体对成簇过程的影响 .本文还详细讨论了反应溶液中不同浓度的PPh3对 [VS4 Cu4]簇合物的51 VNMR化学位移的影响 . The reaction system (NH4 ) 3VS4/ Et4NBr/ CuBr/ PPh3 in CH2Cl2 for self2assembling of [VS 4-Cu n ] ( n from 3 to 6)clusters was simulated in NMR tube. After the relationship between the 51V NMR chemical shift s and the number of copper atoms in this family cluster was established theoretically and experimentally , 51V NMR was used as a pseudo in sit u and real2time method to monitor and identify possible product s during the reaction process. The reaction conditions and mechanism about the formation of [VS4 2Cu n ] clusters were investi2 gated by changing the molar ratios of the reactant s. The result s showed that the concentration of PPh3 has obvious influence on the 51V chemical shift , and their mechanism is discussed in detail.国家自然科学基金重点资助项目 (No.2 9832 0 2 0 ) ; 福建省自然科学基金资助项目 (No .C991 0 0 0 1

Probing self-assembling process of [VS4-Cu-n] (n <= 6) clusters by V-51 NMR

V-51 NMR was used as a new pseudo in situ and nondestructive analytical tool to monitor and identify possible products of [VS4-Cu-n] (n less than or equal to 6) clusters. The reaction of (NH4)(3)VS4/Et4NBr/CuBr/PPh3 systems with various molar ratios in CH2Cl2 were mimicked in NMR tubes. The reaction conditions for the formation of the [VS4-Cu-n] clusters with different coordinate number of copper atoms n were studied. The results show the influence of the ratio among the reactants on the products and reveal the reaction mechanism in solution. This method not only provides some information about reaction mechanism, but also provides a guide in the synthesis of some clusters such as V-Cu-S clusters with less or more coordinate copper number whose reaction conditions (solvent, temperature, pH etc,) are difficult to be determined