Nature of the active silane alcoholysis catalyst in the RuwClx(CO)(y)(PMe3)(z) (w, x, y, z=1 or 2) system; Ru-2(mu-Cl)(2)Cl-2(CO)(4)(PMe3)(2) as a new catalyst for silane alcoholysis in a polar solvent

The dimeric complex Ru-2(mu -Cl)(2)Cl-2(CO)(4)(PMe3)(2) (1) forms an active silane alcoholysis complex in the polar solvent N,N-dimethylamino-acetamid e (DMA). The dynamic behaviour of 1 in DMF-d(7) solution has been investiga ted by variable temperature (VT) H-1 NMR. The solid state structures of 1 a nd cis,cis,trans-RuCl2(CO)(2)(PMe3)(2) (3) have been determined by single c rystal X-ray diffractometry. Using ethylene glycol - triethylsilane as a mo del system, the catalytic activity of 1 in DMA is compared to that of a ser ies of known silane alcoholysis catalysts, including RhCl(PPh3)(3), PdX2 (X = Cl-, OAc-), and cis,cis,trans-[IrH2S2L2]SbF6 (L = PPh3, S = THF). Comple x 3 is not an active silane alcoholysis catalyst in this solvent, but is ac tive in nonpolar solvents. Its structure and spectroscopic signature is, ho wever, different from that of a previously reported catalyst of the same co mposition.