Synthesis of Diruthenium μ-Chloromethylidyne Complex: C–C Bond Formation at the Bridging Carbon Atom via the Reduction of a μ-Chloromethylidyne Ligand

Abstract

The μ-chloromethylidyne complex, [(Cp*RuCl)2(μ-CCl)(μ-Cl)] (2) (Cp* = η5-C5Me5), was prepared by the reaction of a triruthenium pentahydrido complex, [{Cp*Ru(μ-H)}3(μ3-H)2] (1), with CCl4. The reaction of 2 with Zn in an ethylene atmosphere resulted in the formation of a μ-ethylidyne-μ-propylidyne complex, [(Cp*Ru)2(μ-CMe)(μ-CEt)(μ-ZnCl2)] (3). Formation of a μ-propylidyne ligand was unambiguously confirmed by X-ray diffraction, and the μ-propylidyne ligand was probably formed via the migration of an ethyl group derived from ethylene to a transiently generated μ-carbido ligand. A linear μ-carbido complex, [(Cp*Ru)2(μ-C){μ-η1:η2-ZnCl(−OC(OEt)CH═CHC(OEt)O−}2] (4), was prepared by the reaction of 2 with diethyl maleate in the presence of Zn. Two ZnCl moieties were chelated by diethyl maleate, and the Zn-maleate moieties bridged the Ru═C═Ru skeleton in a head-to-tail fashion.