Unprecedented coupling of vinylidene and allenylidene ligands with dithiocarbamates: X-ray structure of [Ru{C(= C = CPh2)SC(NMe2)S}(S2CNMe2)(CO)(PPh3)]

The reaction of [RuCl(PPh3)(2){HB(pz)(3)}] (pz=pyrazol-1-yl) with 4-ethynyl toluene provides [RuCl(=C=CHC(6)H(4)Me4)(PPh3){HB(pz)(3)}] (1a) which reac ts with [Et2NH2][S2CNEt2] to give the metallacyclic alkenyl complex [Ru{C(= CHC6H4Me-4)SC(NEt2)S}(PPh3) {HB(pz)(3)}] (2). The reaction of [RuCl(PPh3)(2 ){HB(pz)(3)}] with diphenylpropynol and Ag[PF6] however provides [Ru(=C=C=C Ph2)(PPh3)(2){HB(pz)(3)}]PF6 (3) or in the absence of silver salts, the neu tral complex [RuCl-(=C=C=CPh2)(PPh3) {HB(pz)(3)}] (4). Both (3) and (4) rea ct with Na[S2CNMe2] to give the metallacyclic allenyl complex [Ru{C(=C=CPh2 )SC(NMe2)S}(PPh3){HB(pz)(3)}] (5). Treatment of [RuHCl(CO)(PPh3)(3)] with d iphenylpropynol and Na[S2CNMe2] provides [Ru(CH=CHCPh2OH)(S2CNMe2)(CO)(PPh3 )(2)] which reacts with excess diphenylpropynol to give the alkynyl complex [Ru(C=CCPh2OH)(S2CNMe2)(CO)(PPh3)(2)]. Protonation of this complex with HB F4 provides the allenylidene complex [Ru(=C=C=CPh2)(S2CNMe2)(CO)(PPh3)(2)]B F4 (6) which reacts with Na[S2CNMe2] to give a kinetic isomer (7k) and ulti mately a structurally characterised thermodynamic isomer of the metallacycl ic allenyl complex [Ru{C(=C=CPh2)SC(NMe2)S}-(S2CNMe2)(CO)(PPh3)] (7t). (C) 1999 Elsevier Science S.A. All rights reserved.