Hydride derivatives of Group 4 metals with the ansa-(SiMe(2))(2)(eta(5)-C5H3)(2) ligand

The dinuclear hydrides [M(CpSi(2)Cp)H(mu-H)](2) [M = Zr (1), Hf (2); (CpSi(2)Cp) = [(SiMe(2))(2)(eta(5)-C5H3)(2)]] have been synthesized by reaction of the corresponding dichloro compounds M(CpSi(2)Cp)Cl-2 [M = Zr, Hf] with LiBHEt(3) in a molar ratio of 1.2. Related deutero derivatives [M(CpSi(2)Cp)D(mu-D)](2) [M = Zr (3), Hf (4)] were obtained by using LiBDEt(3). When the same reaction was carried out with Ti(CpSi(2)Cp)Cl-2, the formation of unidentified titanium(III) species was observed, These compounds have been characterized by the usual analytical and spectroscopic methods. The H-1 NMR study of the reaction of complex 1 with traces of water in deuterated tetrahydrofuran shows that the terminal hydrides are more reactive than the bridging hydrides, and only one of the terminal hydrides reacts selectively. Complex 1 shows a rigid behaviour in the NMR time scale between -80 degrees C (500 MHz) and +80 degrees C (300 MHz).