Complexes of the platinum metals. Part 39. Salicylaldehydato(2–) derivatives of ruthenium, osmium, and iridium. X-Ray crystal structures of [Ru(OC6H4CO)(HOC6H4CH2OH)(CO)(PPh3)2]·CH2Cl2 and [Ru(OC6H4CO)(MeOH)(CO)(PPh3)2]·MeOH

Abstract

Salicylaldehyde reacts with [RuH₂(CO)(PPh₃)₃] in refluxing toluene to afford a ruthenium(II) salicylaldehydato(2–) complex which crystallised from CH₂Cl₂–light petroleum as a dichloromethane-solvated o-hydroxybenzyl alcohol adduct [[graphic omitted])(HOC₆H₄CH₂OH)(CO)-(PPh₃)₂]·CH₂Cl₂, and from CH₂Cl₂–MeOH as the methanol- solvated methanol adduct [[graphic omitted])-(MeOH)(CO)(PPh₃)₂]·MeOH. Formation of the o-hydroxybenzyl alcohol adduct clearly implies the ruthenium-mediated reduction of the CHO group in salicylaldehyde. Carbon monoxide and pyridine react with [[graphic omitted])(MeOH)(CO)(PPh₃)₂]·MeOH to form [[graphic omitted])L(CO)(PPh₃)₂](L = CO or py respectively). The reaction of salicylaldehyde with [OsH₂(CO)(PPh₃)₃] includes a carbonylation step and affords [[graphic omitted])(CO)₂(PPh₃)₂]. Reactions of [RhH(PPh₃)₄] and mer-[IrH₃(PPh₃)₃] with salicylaldehyde in boiling toluene afford [Rh(OC₆H₄CHO)(CO)(PPh₃)₂] and [[graphic omitted])H(CO)(PPh₃)₂] respectively. X-Ray diffraction studies on [[graphic omitted])(HOC₆H₄CH₂OH)(CO)(PPh₃)₂]·CH₂Cl₂and[[graphic omitted])(MeOH)(CO)(PPh₃)₂]·MeOH establish the presence of O,C-chelated salicylaldehydate(2–) ligands in both cases and a monodentate o-hydroxybenzyl alcohol ligand in the former complex.