d-pi Interaction in Transition Metal Cluster Complexes and Their Properties

本文制备了铑和铱的过渡金属团簇配合物，并对其结构和理化性质进行了研究，得到了以下结果：双核铑配合物与氯化硅的反应得到了新型的含氯桥的四核铑配合物。基于x射线结构和DFT理论计算表明，铑双核配合物的单占据分子轨道（SOMO）的对称性和离域性严重依赖于配体。Rh_2^<5+>配合物与轴向膦配体存在siguma_<RhRh>和n_p轨道的大量混合。π <RhRh>*轨道定域在金属原子上，轨道适度离域在桥接配体的π系上。具有桥接氨基吡啶配体的二铱配合物具有低氧化电位和短金属-金属分离。与羟基吡啶配体的Rh_2^<5+>配合物的δ * SOMO在芳香桥接配体上的离域程度约为10%。在晶体中，Rh_2^<4+>和Rh_2^<5+>配合物被pi堆叠排列的芳香桥接配体包裹。部分Rh_2^<5+>配合物的电导率为10^<-7> S cm^<-1>（室温，球团）。研究了含芳香桥接配体的Rh_2^<5+>配合物晶体磁性与晶体结构的关系。方形平面Pd（II）和Pt（II）配合物与硅基或锡基和膦配体表现出容易的扭旋单分子异构化。

Transition metal cluster complexes of rhodium and iridium with aromatic or chloro bridging ligands have been prepared, their structure and physicochemical properties have been studied and following results have been obtained.1. The reaction of dinuclear rhodium complexes with silyl chlorides gave new type of tetranuclear rhodium complexes with chloro-bridges.2. The symmetry and delocalization of the singly occupied molecular orbitals (SOMO) of rhodium dinuclear complexes were shown to be heavily dependent on ligands based on X-ray structures and DFT theoretical calculations. A large mixing ofsiguma_<RhRh> and n_p orbitals were observed for Rh_2^<5+> complexes with axial phosphine ligands. The pi_<RhRh>* orbital is localized on the metal atoms and the orbital is moderately delocalized onto the pi system of the bridging ligands.3. Diiridium complexes with bridging aminopyridine ligands were shown to have low oxidation potentials and short metal-metal separations.4. The delta* SOMO of Rh_2^<5+> complexes with hydroxypyridine ligands were shown to be delocalized onto the aromatic bridging ligands to the extent of about 10 %. In crystal, Rh_2^<4+> and Rh_2^<5+> complexes were packed with pi stacked arrangement of aromatic bridgeing ligands. Electric conductance of some of Rh_2^<5+> complexes were in the order of 10^<-7> S cm^<-1> (room temperature, pellets). Magnetism of crystals of Rh_2^<5+> complexes with aromatic bridging ligands were analyzed in relation to their crystal stucture.5. Square planar Pd(II) and Pt(II) complexes with silyl or stannyl and phosphine ligands showed facile twist-rotational unimolecular isomerization.