Synthesis and structure of isopropyldimethylsilyl-substituted octamethyltitanocene

Reduction of isopropyldimethylsilyl-substituted titanocene dichloride [TiCl2(η5-C5Me4SiMe2Pri)2] (1) by excess magnesium in the presence of excess bis(trimethylsilyl)ethyne (btmse) in tetrahydrofuran at 60 °C yielded a mixture of products amongst them only the trinuclear Ti–Mg–Ti hydrido-bridged complex Mg[Ti(μ-H)2(η5-C5Me4SiMe2Pri)]2 (3) was isolated and characterized. The precursor of titanocene, [Ti(η5-C5Me4SiMe2Pri)2(η2-btmse)] (6), was obtained from the identical system which, after initial formation of [TiCl(η5-C5Me4SiMe2Pri)2] (2), reacted at −18 °C overnight and then the solution was rapidly separated from the remaining magnesium. Titanocene [Ti(η5-C5Me4SiMe2Pri)2] (7) was obtained by thermolysis of 6 at 75 °C in vacuum. Crystal structures of 1, 2, 3, 6, and 7 were determined.