Preparation and structural characterization of [RuCl2(CO)2{Te(CH2SiMe3)2}2] and [RuCl2(CO){Te(CH2SiMe3)2}3]

The objective of the present work was to synthesize mononuclear ruthenium complex [RuCl2(CO)2{Te(CH2SiMe3)2}2] (1) by the reaction of Te(CH2SiMe3)2 and [RuCl2(CO)3]2. However, the stoichiometric reaction affords a mixture of 1 and [RuCl2(CO){Te(CH2SiMe3)2}3] (2). The X-ray structures show the formation of the cis(Cl), cis(C), trans(Te) isomer of 1 and the cis(Cl), mer(Te) isomer of 2. The 125Te NMR spectra of the complexes are reported. The complex distribution depends on the initial molar ratio of the reactants. With an excess of [RuCl2(CO)3]2 only 1 is formed. In addition to the stoichiometric reaction, a mixture of 1 and 2 is observed even when using an excess of Te(CH2SiMe3)2. Complex 1 is, however, always the main product. In these cases the 125Te NMR spectra of the reaction solution also indicates the presence of unreacted ligand.