Cyclopentadienyl and related organo early transition metal complexes: Novel chemical and structural aspects

We report the chemical behaviour of pentamethylcyclopentadienyl titanium alkyls and oxo-alkyls. CpxTiMe3 reacts with carboxylic acids to give titanium (IV) tricarboxylates or dimeric titanium (III) dicarboxylates depending on the molar ratio of the acid, Insertion reactions of CO, CNR and Ph2CN2 into Ti-Me bonds of CpxTiCI2IVIe, [Cp*TiMe Y]2(m. — O) (Y=Me, Cl) and [Cp*TiMe]3(fi-0)3 are studied. The thermal decompósition of this last oxo methyl titanium trimer leads to the formation of the first reported methylidyne titanium derivative [CpxTi]3(|i2 —0)3(|i3- CH). Also the isolation of new alkyl titanium and zirconium metallocenes, (Me2SiCp2)M R2, containing dimethylsilylene bridged-cyclopentadienyl groups is reported along with the reduction of the halotitanium derivatives and the reactions of the dimeric halotitanium (III) complexes [(Me2Si Cp2) Ti (|i— Cl)]2 and similar cyclopentadienyl fulvalene zirconium derivatives [CpZr(ji-Cl)]2((i-CI0H8) with lithium phenylacetylide