Octahedral and trigonal-bipyramidal complexes of ruthenium(II) with bidentate phosphine ligands

Abstract

Six- and five-co-ordinate complexes of ruthenium(II) with the unsymmetrical diphosphine ligand Ph₂P(CH₂)₃PMe₂ have been prepared. Phosphorus-31 n.m.r. spectroscopy indicates that octahedral complexes [RuCl₂(P–P)₂], [RuH(Cl)(P–P)₂], and [RuH(CO)(P–P)₂]ClO₄(P–P = diphosphine ligand) have the all-trans arrangement with Me₂P trans to Me₂P and Ph₂P trans to Ph₂P. The five-co-ordinate complexes [Rux(P–P)₂]BPh₄, where X = Cl or H, are not fluxional at room temperature and have a trigonal-bipyramidal structure with axial PMe₂ groups and equatorial PPh₂ groups. Similar structures are proposed for analogous complexes of Ph₂P(CH₂)₃PMePh and of Ph₂P(CH₂)₃PPh₂.