Oxidative Addition von Tetramethyldiphosphan und -arsan an Cp′–SiMe2–Cp′-überbrückte Molybdän- und Wolframcarbonyl-Komplexe / Oxidative Addition of Tetramethyldiphosphane and -arsane to Binuclear Cp′–SiMe2–Cp′-Bridged Molybdenum and Tungsten Carbonyl Complexes

Abstract

Thermal reaction of Me2Si[Cp′M(CO)3]2 (M = Mo, W; Cp′ = C5H4) with tetramethyldiphosphane and -diarsane gives oxidative coupling products with bridging EMe2-groups (E = P, As). With E = P discrete binuclear compounds are obtained, which on further thermolysis afford new species of the general formula {Me2Si(Cp′M)2(CO)3(μ-PMe2)2} (5). X-Ray structure determination of 5 a (M = Mo) and NMR data show a PMP-heteroallylic system which is bound to the second metal. In the case of M = W a second compound with a mixed hydrido and dimethylphosphido bridge can be isolated, which shows fluxionality in solution. However, the oxidative additions with tetramethyldiarsane lead to insoluble products which are assumed to be polymeric with Cp′–SiMe2–Cp′ as well as AsMe2 bridges linking the metal centers.