Structural eludication of some new titanacycles by means of degradation and 13C NMR studies

Abstract

A reaction between diphenyltitanocene and phenyl(pentafluorophenyl)acetylene in refluxing benzene produces 1,1-bis(η 5-cyclopentadienyl)-2-phenyl-3-(pentafluorophenyl)benzotitanole in 44% yield. Degradation of the product with HCl/CHCl 3 affords titanocene dichloride and Z-1,2-diphenyl-1-(pentafluorophenyl)ethene. Reaction of diphenyltitanocene and phenyl(pentafluorophenyl)acetylene in benzene under photolytic conditions results in the exclusive formation of 1,1-bis(η 5-cyclopentadienyl)-2,5-diphenyl-3,4-di(pentafluorophenyl)titanole. The latter product can also be obtained in 77% yield from a reaction between titanocene dicarbonyl and phenyl(pentafluorophenyl)acetylene in hexane solution. Application of 13C NMR spectroscopy to the structural elucidation of these and related metallacycles is discussed.