SYNTHESIS OF SEMIBRIDGING MU-VINYLIDENE TITANIUM-COPPER AND TITANIUM-GOLD COMPLEXES - CRYSTAL AND MOLECULAR-STRUCTURE OF CP-ASTERISK-TI-2(CL)(MU-C=CH2)AUPPH3

The titanocene-vinylidene intermediate [Cp2Ti=C=CH2] (1; Cp* = C-5(CH 3)(5)), formed by methane elimination from CpTi-2(CH=CH2)(CH3) (2), r eacts with group 12 LM'X complexes ([Me3PCuCl](4) (4a), [Ph3PCuCl](4) (4b), [i-Pr3PCuCl](4) (4c), [Me3PCuC=CPh](4) (4d), [Ph3PAuCl] (4e) (Ti :M' = 1:1)) to give heterodinuclear mu-vinylidene compounds CpTi-2(X) -(mu-C=CH2)M'L (5a-e). The molecular structure of 5e was determined by X-ray diffraction analysis, which revealed a titanium-gold bond asymm etrically bridged by the vinylidene ligand. A semibridging bonding mod e for the C=CH2 group in the new complexes is indicated by NMR spectro scopic and X-ray diffraction data.