[1-Cyclohepta-2,4,6-trienyl-diphenylphosphane]platinum(II) dichloride (4) was prepared by the 1:1 reaction of (cod)PtCl, (cod = eta(4)-cycloocta-1,5-diene) with the phosphane. The reaction of 4 with di(alkyn-1-yl)dimethylstannanes, Me2Sn(C equivalent to C-R)(2) [R = H (a), Me (b), Ph (c), SiMe3 (d)], in boiling THF gave selectively in high yield the monoalkynyl complexes [Ph(2)p(C7H7)]Pt(Cl)C equivalent to C-R (6b,c,d), in which the alkyn-1-yl group is arranged in cis position with respect to the phosphorus atom, and the C7H7 ring is eta(2)-coordinated to platinum through the central C = C bond. The same reaction at room temperature afforded, again selectively and in high yield, the dialkynyl complexes [Ph2P(C7H7)]Pt(C equivalent to C-R)(2) (7a-d). The new complexes were characterised in solution by H-1, C-13, Si-29, P-31 and Pt-195 NMR spectroscopy, and the molecular structures of 4 and 7d were determined by X-ray crystalloggraphy.

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).