Synthesis and structural characterization of novel tetranuclear organotitanoxane derivatives

Synthesis of the novel titanoxane compounds, [(TiCl)(TiOH){(Ti)[mu-(eta(5)-C5Me4SiMe2O-kappa O)](2)(mu-O)}(2)(mu-O)] (4) and [{Ti[mu-(eta(5)-C5Me4SiMe2O-kappa O)](mu-O)} (4)] (5) by controlled reaction of the dinuclear titanium oxo complex [{Ti{mu-(eta(5)-C5Me4SiMe2O-kappa O)}Cl](2)(mu-O)] (1) with 2 equiv of LiOH is reported. Complex 4 is innovative and remarkable. It is one of the rare known examples of tetranuclear stable terminal hydroxo titanium complexes, with an open-chained structure, which coincides with the transient metal monohydroxo proposed in the stepwise pathway employed to justify the formation of the hexanuclear complex [{Ti[mu-(eta(5)-C5Me4SiMe2O-kappa O)](mu-O)}(6)] (3) from 1. H-1 DOSY experiments were used to characterize complex 4. In addition, the structures of compound 5 and of precursor 1 were determined by single-crystal X-ray diffraction studies.