Unbridged homo and hetero dinuclear complexes of Group 6 and 8 metals: synthesis, characterization and comparison of X-ray crystallographic data

Abstract

Several novel compounds of the type Cp/Cp*(CO) 3MM′(CO) n Cp/Cp* (M=Cr, Mo, W; M′=Ru, n=2; M′=Mo, n=3; Cp=C 5H 5, Cp*=C 5Me 5) were synthesized, characterized, their structures compared and preliminary reactivity studies were carried out. The main investigations were focused on the molybdenum and ruthenium containing heterobimetallic compounds Cp(CO) 3MoRu(CO) 2Cp ( 1) as well as Cp(CO) 3MoRu(CO) 2Cp* ( 2) and Cp*(CO) 3MoRu(CO) 2Cp ( 3), the latter two representing a ‘mixed-metal mixed-ligand’ type of complexes with the former ( 1) having identical ligands on both metal cores. For the first time comparison of properties of unbridged bimetallic complexes with molybdenum and ruthenium metal cores was elaborated. The novel Cp(CO) 3MoMo(CO) 3Cp* ( 4) consists of two identical metal cores and of ‘mixed’ ligands. 4 was prepared by treating NaMo(CO) 3Cp with Cp*Mo(CO) 3Br ( 5) after a route for the synthesis of the latter was established. 1 reacted with halides or AlCl 3, respectively, under cleavage of the metal–metal bond to form Cp(CO) n MHal (M=Mo, n=3; M=Ru, n=2; Hal=Br, I, Cl) but was shown to be inert towards substrates such as CO 2, CO, PPh 3 or CS 2 under the chosen conditions. The corresponding anionic species Cp(CO) n M − were obtained when 1 was reacted with alkali metal benzophenyl ketyl.