Thermal stability and reaction of chalcogen-containing metallocenic compounds with elemental chalcogens

Abstract

Dissymmetrical four-membered bimetallocenacycles (t-BuC5H4)2M(μ-S)2M′-(RC5H4)2(M, M′ = Zr, Hf; R = H, t-Bu) have been prepared and found to give redistribution products in solution at 190°C; identification of these products shows that the reaction involves exclusive cleavage of a metal-sulfur bond. Elemental sulfur and selenium react with chalcogen-containing complexes. The reaction is shown to involve the introduction of chalcogenic species in place of the σ-ligands of the complex to give either four-membered bimetallic complexes or catenated pentachalcogen metallocenic compounds. Some examples of insertion of sulfur and tellurium into the zirconium-methyl bond are also described.