Heterodinuclear TiMo and TiW complexes bridged by the (dimethylsilanediyl) dicyclopentadienyl ligand

Abstract

Reactions of the tricarbonyl-molybdenum and -tungsten complexes [M(CO) 3(MeCN) 3] (M = Mo, W or [Mo(CO) 3(mesitylene)] with equimolar amounts of [Ti( η 5-Cp′){( η 5-C 5H 3)(SiMe 2) 2 (C 5H 4)}Cl 2] (Cp′ = C 5H 5, C 5Me 5) lead to the heterodinuclear compounds [Ti( η 5-Cp′)Cl 2{ μ-[(SiMe 2) 2( η 5-C 5H 3) 2]}MH(CO) 3]. These dinuclear complexes are isolated as single cis- and trans-isomers or as mixtures of both depending on the starting complex and the reaction conditions. The molar ratio of the two resulting isomers is controlled by thermodynamic and kinetic factors which prevent the application of stereoselective methods for some of the products. Reaction of the hydrido cis- and trans-complexes with CCl 4 in CH 2Cl 2 allows the isolation of chloro complexes [Ti( η 5-Cp′)Cl 2{ μ-[(SiMe 2) 2( η 5-C 5H 3) 2]} MCl(CO) 3] of the same configuration. All of the new heterodinuclear compounds reported were characterized by their analytical composition, IR and NMR spectroscopy and the molecular structure of cis-[Ti( η 5-C 5Me 5)Cl 2{ μ-[(SiMe 2) 2( η 5-C 5H 3) 2]}WH(CO) 3] was studied by X-ray diffraction methods.