Pentamethylcyclopentadienyltitanium-(III) and -(IV) carboxylates. Crystal structures of [Ti(η-C5Me5)(O2CPh)3] and [{Ti(η-C5Me5)(O2CPh)2}2]

Abstract

The compound [Ti(η-C₅Me₅)Me₃] reacts with 3 equivalents of carboxylic acids HO₂CR (R = Me, Ph, or p-MeOC₆H₄) to give the corresponding tris(carboxylates)[Ti(η-C₅Me₅)(O₂CR)₃]. The X-ray structure of the complex with R = Ph shows the three benzoate ligands acting as chelates, the geometry around Ti is a distorted pentagonal bipyramid and the metal attains the 18-electron configuration. Methyl carboxylate complexes [Ti(η-C₅Me₅)Me_3-n(O₂CR)_n](n= 1 or 2) could not be isolated, but exposure of their solutions to sunlight gave the dimers [{Ti(η-C₅Me₅)(O₂CR)₂}₂]. The X-ray structure of the acetato complex reveals four O₂CMe groups bridging two Ti(C₅Me₅) fragments.