A novel cyclic titanasiloxane derived from [Ph2Si(OH)]2O: synthesis and crystal structure of [Cp*Ti(Cl)(OSiPh2OSiPh2OSiPh2O)]

Reaction of Cp*Ti(OAr)C12 (Ar=2,6-Me2C6H3) with dilithium salt of [Ph2Si(OH)]2O in a 1:1 molar ratio in toluene at room temperature yields titanatrisiloxane ring compound [Cp*Ti(Cl)(OSiPh2OSiPh2OSiPh2O)] (1). Siloxane chain-expansion effect has been observed in the product formation, which is presumed to be a consequence of the ring strain in the titanadisiloxane system. Compound 1 has been characterized by microanalysis, IR, and NMR spectroscopic techniques. The molecular structure of 1 determined by X-ray diffraction reveals that the central eight-membered TiSi3O4 siloxane-ring exists in an unusual butterfly-like conformation.