Reaction of benzyltriphenylphosphonium bicyclo[2.2.1]hepta-2,5-diene-carbonyltrichlororuthenate(II) with Lewis bases

Abstract

A detailed investigation of the reactions of the salt [Ph₃(PhCH₂)P][RuCl₃(CO)(C₇H₈)](I; C₇H₈= bicyclo[2.2.1]-hepta-2,5-diene) with ligands (L) containing Group VB or VIB donor atoms is presented. Several different types of behaviour are found, depending on both the nature and amount of added L. For L = Me₂S, Me₂SO, and CH₂CH–CN, the salts[Ph₃(PhCH₂)P][RuCl₃(CO)L₂], (II), have been isolated in high yield, whereas for L = AsPh₃. SbPh₃, and C₅H₅N, a mixture of (II) and [RuCl₂(CO)L(C₇H₈)], (III), have been obtained [(I) : L = 1 :2 molar ratio]. Reaction of complex (I) with excess of SbPh₃ gives (II), (III), and [RuCl₂(CO)(SbPh₃)₃], (IV). In contrast, reaction of complex (I) with PPh₃(1 :2 molar ratio) gives [{RuCl₂(CO)(PPh₃)₂}₂], (V), whereas with PMe₂Ph, only [RuCl₂(PMe₂Ph)₂(C₇H₈)], (VI), is isolated. A similar complex of type (VI) is formed with PMePh₂, together with some [RuCl₂(CO)(PMePh₂]₃(IV), whilst with 2,2′-bipyridyl or 1,10-phenanthroline (L′), the complexes [{RuCl₂(CO)(L′)}_n], (VII), and [Ph₃(PhCH₂)P][RuC₃CO(L′)], (II), are obtained. Reaction mechanisms consistent with this observed variation in product composition are tentatively proposed.