Heating cis-[Ru(S2CNMe2)(2)(CO)(2)] and [Ru-3(CO)(12)] in xylene affords octanuclear [Ru-8(mu(5)-S)(2)(mu(4)-S)(mu(3)-S)(mu-CNMe2)(2)(mu-CO)(CO)(15)] resulting from the double carbon-sulfur bond cleavage of two dithiocarbarnate ligands. The structure consists of a tri-edge-bridged square of ruthenium atoms with a further ruthenium atom being bound only to the central bridging atom. Studies suggest that it may be formed via the pentanuclear intermediate [Ru-5(mu(4)-S)(2)(mu-CNMe2)(2)(CO)(11)] which is formed in trace amounts. (c) 2007 Elsevier B.V. All rights reserved.

Traps-[RuCl2(CO)(2)(PEt3)(2)] reacts with two equivalents of a series of 1,1-dithiolate ligands to form the bis(dithiolate) complexes, cis-[Ru(CO)(PEt3)(S2X)(2)] (X = CNMe2, CNEt2, COEt, P(OEt)(2), PPh2). Two intermediates have been isolated; trans-[Ru(PEt3)(2)Cl-(CO){S2P(OEt)(2)}] and trans-[Ru(PEt3)(2)(CO)(eta(1)-S2COEt)(eta(2)-S2COEt)], allowing a simple reaction scheme to be postulated involving three steps; (i) initial replacement of cis carbonyl and chloride ligands, (ii) substitution of the second chloride, (iii) loss of a phosphine. Thermolysis of cis-[Ru(CO)(PEt3)(S2CNMe2)(2)] with Ru-3(CO)(12) in xylene affords trinuclear [Ru-3(mu(3)-S)(2)(PEt3)(CO)(8)] as a result of dithiocarbamate degradation. Crystal structures of cis-[Ru(CO)(PEt3)(S2X)(2)] (X = NMe2, COEt), trans-[Ru(PEt3)(2)Cl(CO){S2P(OEt)(2)}], trans[Ru(PEt3)(2)(CO)(eta(1)-S2COEt)(eta(2)-S2COEt)] and [Ru-3(mu(3)-S)(2)(PEt3)(CO)(8)] are reported. (c) 2005 Elsevier B.V. All rights reserved.

Two methods were used to synthesise [Ru-3(mu-H)(2)(mu(3)-PPh)-(CO)(7) (mu-dppm)] (3) (dppm = Ph2PCH2PPh2), the subject of this paper. Treatment of [Ru-3(CO)(10)(mu-dppm)] (1) with phenylphosphane in refluxing THF gave both [Ru-3(mu-H)(2)(mu-PHPh)-(CO)(8)(mu-dppm)] (2) and [Ru-3(mu-H)(2)(mu(3)-PPh)(CO)(7)(mu-dppm)] (3). Cluster 2 converts to 3 in refluxing THF. Alternatively the phenylphosphinidene cluster [Ru-3(mu-H)(2)(mu(3)-PPh)(CO)(9)] (4), prepared by the reported method of treating [Ru-3(CO)(12)] with phenylphosphane, reacts with dppm to produce cluster 3. The single-crystal X-ray structures of 2 and 3 are reported. Hydride mobility in [Ru-3(mu-H)(2)(mu(3)-PPh)(CO)(7)(mu-dppm)] (3) was analysed by variable-temperature H-1 and P-31(H-1) NMR methods. The variations in the spectra with temperature could not be interpreted by a single process, several of which were explored and which gave inadequately matching computed and experimental spectra. However, the spectra were successfully analysed by two concurrent processes, both involving the migration of hydride ligands between Ru-Ru edges. The faster process leads to the exchange of the nonequivalent phosphorus nuclei but not hydride exchange, whereas the hydrides are also exchanged in the slower process. Both processes require hydride ligand migration from one Ru-Ru edge to a vacant one. The hydride ligand bridging the same pair of ruthenium atoms as the dppm ligand is the slower to migrate. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).

Turnstile rotation is suppressed in the equatorially substituted cluster [Os(3)(mu-H)(2)(mu(3)-S)(CO)(8){(S)-PhCHMeNH(2)}] which was separated by HPLC into two diastereomers which do not interconvert at room temperature and epimerize only slowly at 90 degreesC.