Dimolybdenum complexes with sulfide and thiolate ligands as precursors to mixed-metal clusters: Crystal structure of [Mo2Ru2(mu(3)-S)(2)(mu-SPri)(2)(CO)(4)(eta-C5H5)(2)]

The reaction of [Mo-2(CO)(4)(mu-C(2)Me(2))(eta-C5H5)(2)] 1 with thiols, RSH, in boiling toluene provides a useful new route to the known compounds [Mo-2(mu-S)(2)(mu-SR)(2)(eta-C5H5)(2)] (R = Et 2a or Pr-1 2b) in 40-45% yield. Both compounds exist as two isomers which were separated by chromatography For R = Et. The sulfur ligands in these complexes are formed by dealkylation of the thiols at the dimolybdenum centre. Reaction of 2 with [Ru-3(CO)(12)] in refluxing tetrahydrofuran produced high yields of the mixed-metal clusters [Mo2Ru2(mu(3)-S)(2)-(mu-SR)(2)(CO)(4)(eta-C5H5)(2)] 3; the crystal structure of the Pr-1-substituted complex 3b has been determined, The cluster consists of a tetrahedral metal core with both Mo2Ru faces capped by triply bridging sulfides. One of the thiolate ligands still bridges the molybdenum-molybdenum edge, but the other has migrated to the ruthenium-ruthenium edge.