Hydron-Transfer Processes Involving an Organotitanium Oxide and Alcohols

Thermal treatment of the mu(3)-alkylidyne complexes [{Ti(eta(6)-C5Me5)(mu-O)}(3)(mu(3)-CR)] [R = H (1), Me (2)] with alcohols (Ph3COH, Ph2CHOH, PhCH2OH, Ph2CMeOH, tBuOH, Me2CHOH and MeCH2OH) leads to Partial hydronation of the alkylidyne moiety supported on the organometallic oxide [Ti-3(eta(5)-C5Me5)(3)O-3] and formation of the new oxo derivatives [{Ti-3(eta(5)-C5Me5)(mu-O)}(3)(mu-CHR)(OR')] [R = H, R' = Ph3C (3), Ph2CH (4), Ph2CMe (5), tBu (6); R = Me, R' = Ph3C (7), Ph2CH (8), Ph2CMe (9), tBu (10), Me2CH (11), MeCH2 (12)]. The mu-CHR group in those Species lies above the Ti3O3 ring while the alkoxide ligand is located below it, To gain insight into the mechanism of these reactions, density functional calculations have been performed oil the incorporation of alcohols into the model complexes [{Ti(eta(6)-C5H5)(mu-O)}(3)(mu(3)-CR)] [R = H (1H), Me (2H)]. Irradiation of solutions containing 1 and the alcohols leads to the Compounds [{Ti(eta(6)-C5H5)(mu-O)}(3)(mu-CH2)(OR')] [R' = Ph3C (13), Ph2CH (14), Ph2CMe (15), tBu (16)] where the. methylene (mu-CH2) and OR' ligands are located cis with respect to the Ti3O3 unit. Finally, irradiation of solutions of 1 or 2 and Ph3COH in a 1:2 ratio gives the compounds [{Ti(mu(3)-O})eta(5)-C5Me5)(mu-CHR)(OCPh3)(2)] [R = H (19), Me (20)]. The molecular structures of 3, 5, 10, 11, 15 and 20 have been established by single-crystal X-ray analysis. ((C) Wiley-VCH Verlag GmhH & Co. KGaA, 69451 Weinheim, Germany, 2009)