The interaction of [Cp ∗RuCl(dippe)] and [CpRuCl(dippe)] with alkynols: hydroxyvinylidene, allenylidene and related derivatives (dippe  1,2-bis(diisopropylphosphino)ethane)

Abstract

The reactions of [Cp ∗RuCl(dippe)] and [CpRuCl(dippe)] (dippe  1,2-bis(diisopropylphosphino)ethane) with several alkynols HCCC(OH)RR′ (RR′H, Me; RMe, R′Ph) have been studied. These reactions leads to the formation of the corresponding allenylidene derivatives, although in some cases hydroxyvinylidene complexes were isolated as intermediates in such process. The X-ray crystal, structure of [CpRuCCCMePh(dippe)][BPh 4] was determined. In the course of the reaction of [CpRuCl(dippe)] with HCCC(OH)Me 2, there is evidence for the formation of a deep bluedimeric aklynyl-carbene (or alkenyl-allenylidene) complex [{CpRu(dippe)} 2(μ-C 10H 11)][BPh 4] resulting formally from the coupling of two allenylidene moieties followed by the loss of one proton. The reaction of [Cp ∗RuCCCMePh(dippe)][BPh 4] with KOBu′ leads to the ene-yne derivative [Cp ∗Ru(CCC(Ph)CH 2)(dippe)] as result of the deprotonation of the allenylidene ligand at the δ-position. This compound was structurally characterized by single crystal X-ray crystallography. In an attempt to obtain the primary allenylidene complex [Cp ∗RuCCCH 2(dippe)][BPh 4] by dehydration of the hydroxyvinylidene [Cp ∗RuCCHCH 2OH(dippe)][BPh 4] using P 2O 5, the previously reported carbonyl complex [Cp ∗Ru(CO)(dippe)][BPh 4] was obtained and its crystal structure determined. This is also accessible by aerial oxidation of the hydroxy-vinylidene derivative.