Experimental and theoretical studies of the reactions of electrophiles with cationic formyl complexes; formation of methoxy- and hydroxy-carbene complexes of ruthenium(II) and osmium(II)

Abstract

Complexes of the form trans-[M(CHO)(CO)(P–P)₂][SbF₆][M = Ru or Os, P–P = Ph₂PCH₂CH₂PPh₂(dppe) or o-(Ph₂P)₂C₆H₄(dppb)] react with CF₃SO₃R (R = Me or H) at –30 °C to give trans-[M(CHOR)(CO)(P–P)₂][SbF₆][CF₃SO₃], which have been isolated and spectroscopically characterised. EHMO (extended Hückel molecular orbital) calculations demonstrate that the site of attack for hard or soft electrophiles is expected to be the formyl oxygen atom (as is observed) but that hard nucleophiles will attack the carbonyl carbon atom and soft nucleophiles the formyl carbon atom.