Reactions of alkaline earth metal or al slurries with bis-cyclopentadienyl complexes of some early transition metals

Abstract

Slurries of Mg, Ca, Ba and Al, prepared by cocondensation of metal vapour with volatile organic solvents, especially toluene, at –196°C, reacted at ambient temperature with some bis-cyclopentadienyl complexes of Ti, Zr, Hf, V and Cr. [TiCl 2Cp 2] (Cp = η 5-C 5H 5) with slurries Al in hexane or toluene, or Mg or Ba, in toluene, formed [TiClCp 2] 2 accompanied by side-products. From related reactions with slurries of Mg in tetrahydrofuran (THF), [TiCl 2Cp(THF)] was obtained and with Ca-toluene slurries an unstable paramagnetic dihydrido complex of Ti(III) was observed by using ESR spectroscopy. Reactions of [TiPh 2Cp 2 with slurries of Al or Ba in toluene yielded a form of “titanocene” (TiC 10H 10) and ESR studies of these reactions revealed related paramagnetic species in solution. Reaction of slurries of Al, Mg or Ba with [TiMe 2Cp 2] produced several different paramagnetic products which were studied by ESR spectroscopy, and the reaction of metal slurries with the complexes [MR 2Cp 2] (M = Ti, R = OPh; M = Zr or Hf, R = Cl or Me), [VRCp 2] (R = Cl or Me), and [CrCp 2] are also reported.