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Type: Artigo de periódico
Title: 1,2,3-triphenyiphosphirene Derivatives Of The Iridium Carbonyl Clusters [hir4(co)9l(μ-pph2)] (l = Co, Pph3) Resulting From Substitution, Insertion And Hydrometallation Processes 1
Author: Hitchcock P.B.
Nixon J.F.
Vargas M.D.
Ziglio C.M.
Abstract: 1,2,3-Triphenylphosphirene reacts with [HIr4(CO)10(μ-PPh2)] 1, at room temperature, to afford [Ir4(CO)8(μ3-μ 2PhPCPh=CPh)(μ-PhPCPh=CHPh)(μ-PPh2)] 2 which contains the phosphametallacycle (μ3-η2-PhPCPh=CPh) and the phosphidoalkenyl (μ-PhPCPh=CHPh) ligands arising from insertion and hydrometallation processes respectively. In contrast, the PPh3 derivative of 1, [HIr4(CO)9(PPh3)(μ-PPh2)] 3, reacts selectively at room temperature with the phosphirene to give only CO substitution products, [HIr4(CO)9-n(PPh3)(η 1-PhPCPh=CPh)n(μ-PPh2)] (n=1,4 and 2, 5) which are the first carbonyl cluster compounds containing intact η1-ligated phosphirene rings. High yield conversion of compound 4 into the phosphametallacycle species [HIr4(CO)7(PPh3)(μ3-η 2-PhPCPh=CPh)(μ-PPh2)] 6 is achieved under mild thermolytic conditions. An insight into the mechanism of formation of 2 was given by the reaction of the phosphirene ring with the anion [Ir4(CO)10(μ-PPh2)]- 1a derived from 1, followed by protonation, which gave [HIr4(CO)8(μ3-η 2-PhPCPh=CPh)(μ-PPh2)] 7, which is analogous to 6 with a CO ligand replacing PPh3. Quantitative conversion of the hydride phosphametallacycle 7 into the labile phosphidoalkenyl cluster [Ir4(CO)n(μ-PhPCPh=CHPh)(μ-PPh2)] 8 is easily achieved in the presence of CO (1 atm, RT, 2 h), as a result of the reductive elimination of a C-H group. Compound 8 undergoes facile CO dissociation and co-ordination of the phosphidoalkenyl C=C bond to the metal centre to produce [Ir4(CO)9(μ3-η 3-PhPCPh=CHPh)(μ-PPh2)] 9. The molecular structures of compounds 2,4,6 and 9 were established by X-ray diffraction studies and the structures of all compounds in solution were investigated by a combination of 1H and 31P{1H} NMR studies. © The Royal Society of Chemistry 2000.
Citation: Journal Of The Chemical Society, Dalton Transactions. , v. , n. 15, p. 2527 - 2536, 2000.
Rights: fechado
Identifier DOI: 10.1039/b003002n
Date Issue: 2000
Appears in Collections:Unicamp - Artigos e Outros Documentos

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