Carbonyl substitution chemistry of some trimetallic transition metal cluster complexes with polyfunctional ligands

Abstract

The trimetallic clusters [Ru 3(CO) 10(dppm)], [Ru 3(CO) 12] and [RuCo 2(CO) 11] react with a number of multifunctional secondary phosphine and tertiary arsine ligands to give products consequent on carbonyl substitution and, in the case of the secondary phosphines, PH activation. The reaction with the unresolved mixed P/S donor, 1-phenylphosphino-2-thio(ethane), HSCH 2CH 2PHPh ( LH 2), gave two products under various conditions which have been characterised by spectroscopic and crystallographic means. These two complexes [Ru 3(μ-dppm)(H)(CO) 7(LH)] and [Ru 3(μ-dppm)(H)(CO) 8(LH)Ru 3(μ-dppm)(CO) 9], show the versatility of the ligand, with it chelating in the former and bridging two Ru 3 units in the latter. The stereogenic centres in the molecules gave rise to complicated spectroscopic data which are consistent with the presence of diastereoisomers. In the case of [Ru 3(CO) 12] the reaction with LH 2 gave a poor yield of a tetranuclear butterfly cluster, [Ru 4(CO) 10(L) 2], in which two of the ligands bridge opposite hinge wingtip bonds of the cluster. A related ligand, HSCH 2CH 2AsMe(C 6H 4CH 2OMe), reacted with [RuCo 2(CO) 11] to give a low yield of the heterobimetallic Ru–Co adduct, [RuCo(CO) 6(SCH 2CH 2AsMe(C 6H 4CH 2OMe))], which appears to be the only one of its type so far structurally characterised. The secondary phosphine, HPMe(C 6H 4(CH 2OMe)) and its oxide HP(O)Me(C 6H 4(CH 2OMe)) also react with the cluster [Ru 3(CO) 10(dppm)] to give carbonyl substitution products, [Ru 3(CO) 5(dppm)(μ 2-PMe(C 6H 4CH 2OMe)) 4], and [Ru 3H(CO) 7(dppm)(μ 2,η 1-P( O)Me(C 6H 4CH 2OMe))]. The former consists of an open Ru 3 triangle with four phosphide ligands bridging the metal–metal bonds; the latter has the O atom symmetrically bridging one Ru–Ru bond, the P atom being attached to a non-bridged Ru atom.