TO BEND OR NOT TO BEND---STRUCTURAL STUDIES OF OXO-BRIDGED BINUCLEAR TITANIUM COMPLEXES. Michael Y. Chiang, Bella M. Chen, Hui-Wen Feng, Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan, Republic of China

Oxo-bridged binuclear transition metal complexes offen display a wide MOM angle much larger than the HOH angle of 104.5deg. found in water. In extreme case it reaches the 180deg. limit becoming linear. Although most people agree the geometry may be governed by steric reasons, no one can be sure of that. We have examined three crystal structures of the same complex, u-oxo-bis[chlorobis(2,4-pentanedio-nato)titanium(IV)], and found troth linear and bent Ti-O-Ti moieties. The bent geometry was found in the crystal structure done by Watenpaugh et al. involving the aforementioned Ti complex with cocrystallized chloroform (1). However we have found two structures of the same complex, with and without cocrystallized acetonitrile, both displaying linear Ti-O-Ti framework. Detailed structural comparison among the three crystal structures as well as other related group IVB complexes will be presented.

(1) K. Watenpaugh and C. N. Caughlan, Inorganic Chemistry 6, 963-967 (1967)