1H, 13C and 29Si NMR study of acetylide and parallel alkyne substituted Ru 3 and Os 3 clusters derived from HCCR (R=SiMe 3, SiPh 3 and CMe 3). X-ray crystallographic study of [(μ-H)M 3(CO) 9(CCR)] (M=Ru, R=SiMe 3, SiPh 3; M=Os, R=SiPh 3, CMe 3) and [Ru 3(μ-CO)(CO) 9(HCCR)] (R=CMe 3)

Abstract

A series of alkyne parallel μ 3-η 2-(//) substituted trinuclear cluster derivatives has been synthesized, containing the alkynes (HCCR, R=SiMe 3, SiPh 3 and tBu) coordinated to Ru 3 and Os 3 units and then converted into the corresponding chemically related acetylide derivatives. A 1H, 13C and 29Si NMR study was carried out for all the complexes and the results are also analyzed in comparison with results of Extended Hückel Molecular Orbital calculations carried out on the complexes and the free alkynes. In the acetylide derivatives, 13C 1H and 187Os 1H couplings involving the hydride, were measured. The 13C 29Si couplings for all the derivatives which contain silicon shows the changes in hybridization of the C β. The structures of [(μ-H)Ru 3(CO) 9(CCR)] (R=SiMe 3 and SiPh 3) and [(μ-H)Os 3(CO) 9(CCR)] (R=SiPh 3 and CMe 3) and [Ru 3(CO) 10(HCCR)] (R=CMe 3) were determined by single crystal X-ray diffraction methods.