Hydride derivatives of Group 4 metals with the ansa-(SiMe2)2(η5-C5H3)2 ligand

Abstract

The dinuclear hydrides [M(CpSi2Cp)H(η-H)]2[M = Zr (1), Hf (2); (CpSi2Cp) = [(SiMe2)2(η5-C5H3)2]] have been synthesized by reaction of the corresponding dichloro compounds M(CpSi2Cp)Cl2 [M = Zr, Hf] with LiBHEt3 in a molar ratio of 1:2. Related deutero derivatives [M(CPSi2Cp)D(η-D)]2 [M = Zr (3), Hf (4)] were obtained by using LiBDEt3. When the same reaction was carried out with Ti(CpSi2Cp)Cl2, the formation of unidentified titanium(III) species was observed. These compounds have been characterized by the usual analytical and spectroscopic methods. The 1H 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°C (500 MHz) and + 80°C (300 MHz).