Preparation of Carboxylato-Coordinated Titanium Alkoxides from Carboxylic Anhydrides: Alkoxido Group Transfer from Metal Atom to Carbonyl Group

Reaction of titanium(IV) isopropoxide, Ti(OiPr)4, with an equimolar amount of phthalic anhydride resulted in the transfer of an isopropoxido group from the metal atom to one carbonyl group of the anhydride and coordination of the thus formed monoester to the titanium atom. One monoester ligand in Ti2(OiPr)6(μ2-OOC-C6H4-COOiPr)(η1-OOC-C6H4-COOiPr)(iPrOH) is bridging and the other is η1-coordinated. When the reaction is performed in the presence of 1 mol-equiv. of acetic acid, the oxido cluster Ti6(μ3-O)6(OiPr)6(μ2-OOC-C6H4-COOiPr)6 was instead obtained. The μ3-oxygen groups in the latter compound are due to esterification of acetic acid by the cleaved isopropyl alcohol.