Synthetic studies of organodi-π-cyclopentadienyl- titanium (III) derivatives

Abstract

Two synthetic routes to compounds of the type π-Cp 2Ti IIIR (R=CH 3, CH 2Si(CH 3) 3, C 6F 5) have been investigated: (a) chemical reduction of π-Cp 2Ti IV(R)Cl by zinc or aluminum metal in tetrahydrofuran, and (b) conventional organometallic syntheses using organo-lithium or -magnesium reagents and [π-Cp 2Ti IIICl] 2. The preferred route is via an organolithium reagent, since chemical reduction gives a mixture of products. Green, monomeric complexes (R = CH 2Si(CH 3) 3, C 6F 5) were isolated and characterised. From the reaction of π-Cp 2Ti IVCl 2 and trimethylsilylmethyllithium in a 1/1 ratio, π-CpTi IV [CH 2Si(CH 3) 3] 3 was obtained. Unlike π-Cp 2Ti IIIC 6F 5, π-Cp 2Ti IIICH 2Si(CH 3) 3 does not form a blue complex with molecular nitrogen.