The chemistry of polynuclear compounds. Part XXIII. Some monomeric carboxylate derivatives of ruthenium carbonyl

Abstract

The reactions of [Ru₃(CO)₉(PPh₃)₃] or [Ru(CO)₄(PPh₃)] with carboxylic acids, RCO₂H (R = H, Me, or Et) leads to the previously reported dimeric compounds [Ru₂(CO)₄(PPh₃)₂(RCO₂)₂]. In contrast similar reactions with [Ru(CO)₃(PPh₃)₂] yield new monomeric complexes of the type [Ru(CO)₂(PPh₃)₂(RCO₂)₂]. No evidence has been found for the production of hydrido-derivatives from this reaction. On the basis of i.r. spectroscopic data the carboxylate groups are considered to function as monodentate ligands in the new complexes. I.r. and ¹H n.m.r. spectroscopic data are consistent with a structure involving a cis-arrangement of both the two carbonyl groups and phosphine ligands and a trans-arrangement for the two monodentate RCO₂ ligands for these complexes.