Organogermanium complexes of molybdenum and tungsten

Abstract

The complexes π-C₅H₅(CO)₃M·GeR₃(M = Mo, W; R = Me, Et, Prⁿ) are stable to water, but are oxidised in air. They are thermally stable to 200° and sublime readily in vacuo Infrared, proton magnetic resonance, and mass spectra are reported. Diethylphosphine displaces one CO group while reaction with Ph₃P gives evidence of an intermediate, π-C₅H₅(CO)₃(Ph₃P)M,GeR₃, which decomposes to π-C₅H₅(CO)₂(Ph₃P)·MGeR₃. Reagents which cleave the metal–germanium bond are: HCl, C₂H₄Br₂, EtBr, and l₂. The latter, present in excess, also displaces CO giving π-C₅H₅(CO)₂Ml₃. Magnesium bromide also cleaves the M–Ge bond forming the transition metal-Grignard reagents which probably involve 3-co-ordinate magnesium, π-C₅H₅(CO)₃M·MgBr(THF). Mercuric chloride also cleaves the W–Ge bond giving π-C₅H₅(CO)₃W·HgCl which, in preliminary studies, has been further used in the cleavage of other metal–metal bonds.