Structure and Physical Properties of Bridging Chalcogenide Cluster Complexes

本研究项目的目的是通过三核钼和钨硫化物簇合物的缩合反应合成三面体金属簇合物，并对产物进行X射线结构研究，以阐明氧化态与M-M键距和簇合物骨架扭曲的关系、分子轨道计算以及电子光谱和磁学性质。主要目标是具有与超导Chevrel相化合物相同的簇合物骨架的分子簇合物。我们通过[Mo3X4Cl4(PET3)5]的还原二聚反应合成了六核簇合物[Mo6X8(PET3)6](X=S，Se)。用汞齐钠还原生成了单电子还原的簇合物，并用X-射线衍射仪测定了它们的结构。硒衍生物的Mo-Mo键距比硫类似物的要长。中性的簇合物具有规则的八面体骨架，而还原的簇合物略有扭曲。这一结果修正了以前关于固态Chevrel化合物八面体扭曲的理论。[Mo_3X_4Cl_4(PET_3)_5]与M(CoD)_2(M=Ni，Pt)缩合形成五核簇合物[Mo_3Ni_2X_4Cl4(PET_3)_5]和[Mo_3PT_2S_4Cl4(PET_3)_6]。钼镍簇合物为方形平面，钼铂簇合物为梯形结构。

The purpose of this research project is the synthesis of deltahedral metal cluster complexes by the condensation of trinuclear molybdenum and tungsten chalcogenide clusters, and the X-ray structural study of the products to elucidate the relationships between the oxidation states and the M-M bond distances and the distortion of the cluster frameworks; molecular orbital calculation and the electronic spectra and magnetism. The main targets have been the molecular cluster complexes having the same cluster skeletons as those of the superconducting Chevrel phase compounds.We have established the synthesis of the hexanuclear cluster complexes [Mo_6X_8(PEt_3)_6] (X = S, Se) by the reductive dimerization of [Mo_3X_4Cl_4(PEt_3)_5]. The reduction with sodium amalgam formed one-electron reduced cluster complexes and the structures of these four complexes have been solved by X-ray. The Mo-Mo bond distances for the selenium derivatives are longer than those of the sulfur analogs. The neutral cluster complexes have regular octahedral frameworks, whereas the reduced ones are slightly distorted. The results have corrected a previous theory for the solid state Chevrel compounds concerning the distortion of the octahedra. The tungsten analogs of the Chevrel model compounds have also been prepared.The condensation of [Mo_3X_4Cl_4(PEt_3)_5] with M(cod)_2 (M = Ni, Pt) formed pentanuclear cluster complexes, [Mo_3Ni_2X_4Cl_4(PEt_3)_5] and [Mo_3Pt_2S_4Cl_4(PEt_3)_6]. The molybdenum-nickel cluster has a square-planar and the molybdenum-platinum cluster has a ladder structure.