Multiple oxidative addition of diphenyl-2-thienylphosphine selenide to [Ru-3(CO)(12)]: crystal and molecular structure of [Ru-3(mu(3)-Se)(mu-PPh2)(mu-eta(1):eta(2)-C4H3S)(CO)(6){P(C4H3S)Ph-2}]

The reaction of Ph-2(C4H3S)PSe with [Ru-3(CO)(12)] affords the open triangu lar 50-electron cluster [Ru-3(mu(3)Se)(2)(CO)(7){P(C4H3S)Ph-2}(2)] (1) and the 48-electron cluster [Ru-3(mu(3)-Se)(mu-PPh2)(mu-C4H3S)(Co)(6){P(C4H3S)P h-2}] (2) derived by the multiple fragmentation of one phosphine ligand on the metal triangle. The same cluster core is also exhibited by a major ioni c fragment detected in the mass spectrum of 1, suggesting that 2 is a secon dary product derived from decomposition of 1. The molecular structure of 2, determined by X-ray diffraction methods, shows two (a phosphide and a thie nyl) ligands bridging two sides of the metal triangle, which is capped by t he selenium atom ligand. The bridging (mu-eta(1):eta(2)) thienyl moiety app roaches a side of the metal triangle with the sigma-bound carbon nearly cop lanar with the ruthenium atoms. (C) 2000 Elsevier Science S.A. All rights r eserved.