Intramolecular protonation and other mechanisms for substitution reactions of hydrido(thiolato)- and di(thiolato)-ruthenium(II) phosphine complexes

Reactions of cct-RuH(SR) (CO)(2)(PPh3)(2) (1) (cct = cis, cis, traits) with R’SH provide cct-RuH(SR’) (CO)(2)(PPh3)(2) (R = alkyl, aryl); based on described kinetic data, the proposed mechanism involves PPh3 loss, coordination of R’SH, intramolecular protonation of RS- by R’SH, and RSH elimination. The intramolecular protonation step circumvents a potentially slow RSH reductive elimination step. A similar mechanism is proposed for the thiol exchange reactions of cct-Ru(SR)(2)(CO)(2)(PPh3)(2) (2). A corresponding dissociative mechanism is also proposed for the reaction of 1 with P(p-tolyl)(3), which gives cct-RuH(SR) (CO)(2)(PPh3) (P(p-tolyl)(3)) and cct-RuH(SR) (CO)(2)(P(p-tolyl)(3))(2). Other reactions described include the reactions of 1 with H-2, CO, HCl and PPh3, and the reactions of 2 with P(p-tolyl)(3) and H-2. Exposure to light causes 2 to dimerize in solution. (C) 1998 Elsevier Science S.A. All rights reserved.