Synthesis and characterization of complexes containing Ti-O-Si moieties. Catalytic activity in olefin epoxidation

Reaction of Cp*TiMe3] with O(SiPh2OH)2 yields the titanium siloxide derivative Cp*TiMe{(OSiPh2)2O}]. Complex reacts with H2O to yield the corresponding oxo-titanium derivative (Cp*Ti{(OSiPh2)2O})2(micro-O)]. The molecular structure of complex has been established by X-ray diffraction. Complex reacts with triphenylsilanol to give the asymmetric titanium siloxide Cp*Ti(OSiPh3){(OSiPh2)2O}]. Treatment of the dinuclear titanium compound (Cp*TiCl2)2(micro-O)] with an equimolar amount of O(SiPh2OH)2 yields complex (Cp*TiCl)2{micro-(OSiPh2)2O}(micro-O)] in which the disiloxide moiety is bridging two titanium atoms. The structure of has been determined by X-ray diffraction. Reaction of Cp*TiMe3] with HOSiPh3 yields the titanium triphenylsiloxide Cp*TiMe2(OSiPh3)]. Complex reacts with water to yield {Cp*TiMe(OSiPh3)}2(micro-O)]. The triflate compound Cp*Ti(OSiPh3)2(OTf)] can be prepared by reaction of with HOTf and triphenylsilanol. We have tested the catalytic activity of some of the complexes in the epoxidation of cyclohexene.