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RESEARCH PRODUCT

Synthesis, reactivity and structures of ruthenium carbonyl clusters with telluride and hydride ligands

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The reaction of [Cp* 2 Nb(Te 2 H)] ( 1 ) (Cp*=C 5 Me 5 ) with [Ru 3 (CO) 12 ] in boiling toluene gave [Ru 3 (μ 2 -H) 2 (CO) 9 (μ 3 -Te)] ( 2 ), [Ru 6 (μ 3 -H)(CO) 15 (μ 3 -Te) 3 ][Cp* 2 Nb(CO) 2 ] ( 3 ) and [Ru 5 (μ 2 -H)(CO) 14 (μ 4 -Te)][Cp* 2 Nb(CO) 2 ] ( 4 ) along with already known [Ru 4 (CO) 11 (μ 4 -Te) 2 ] ( 5 ). Complexes 2 – 4 were analytically and spectroscopically characterized and X-ray diffraction analyses of 3 and 4 were carried out. The anion of 3 is built up of a triangular hexametallic core of C 3 v symmetry, in which the central Ru 3 triangle, being bridged by a μ 3 -H ligand, is composed of three corner-linked Ru 3 Te tetrahedra. The main structural feature of the anion of 4 is a Ru 5 Te octahedron. The cations in 3 and 4 are known niobocenedicarbonyl species. The reaction of 2 with bis(diphenylphosphino)methane (dppm) gave [Ru 3 (μ 2 -H) 2 (CO) 7 (dppm)(μ 3 -Te)] ( 6 ). Low temperature 1 H-NMR spectroscopy and X-ray diffraction analysis show an unsymmetrical distribution of both hydride ligands over the triangular Ru 3 basis of the Ru 3 Te tetrahedron. The reaction of 5 with dppm gave [Ru 3 (CO) 7 (dppm)(μ 3 -Te) 2 ] ( 7 ) and known [Ru 4 (CO) 9 (dppm)(μ 4 -Te) 2 ] ( 8 ). The crystal structure of 7 reveals a square pyramidal arrangement of the Ru 3 Te 2 core. Electrochemical studies of 5 show this complex to be able to consume up to four electrons in reversible steps.