title: Mechanism of protonation of [Pt(3)(mu-PBu(t)(2))3(H)(CO)2], yielding the hydride-bridged [Pt(3)(mu-PBu(t)(2))2(mu-H)(PBu(t)(2)H)(CO)2]OTf (Tf=CF(3)SO(2)), and the spectroscopic and theoretical characterization of a kinetic intermediate.
abstract: The reaction of the Pt(I)Pt(I)Pt(II) triangulo cluster Pt(3)(micro-PBu(t)()(2))(3)(H)(CO)(2) (1) with TfOH (Tf = CF(3)SO(2)) affords the hydride-bridged cationic derivative [Pt(3)(mu-PBu(t)()(2))(2)(mu-H)(PBu(t)()(2)H)(CO)(2)]OTf (2). With TfOD the reaction gives selectively [Pt(3)(mu-PBu(t)(2))(2)(mu-D)(PBu(t)(2)H)(CO)(2)]OTf (2-D(1)), implying that the proton is transferred to a metal center while a P-H bond is formed by the reductive coupling of one of the bridging phosphides and the terminal hydride ligand of the reagent. The reaction proceeds through the formation of a thermally unstable kinetic intermediate which was characterized at low temperatures, and was suggested to be the CO-hydrogen-bonded (or protonated) [Pt(3)(mu-PBu(t)(2))(3)(H)(CO)(2)].HOTf (3). An ab initio theoretical study predicts a hydrogen-bonded complex or a proton-transfer tight ion pair as a possible candidate for the structure of the kinetic intermediate.
authors.affiliation: Dipartimento di Chimica e Chimica Industriale dell' Università di Pisa, Via Risorgimento 35, Via V. Alfieri 1, I-56010 Ghezzano (Pisa), Italy.
authors.forename: A
authors.initials: A
authors.lastname: Fortunelli
authors.forename: P
authors.initials: P
authors.lastname: Leoni
authors.forename: L
authors.initials: L
authors.lastname: Marchetti
authors.forename: M
authors.initials: M
authors.lastname: Pasquali
authors.forename: F
authors.initials: F
authors.lastname: Sbrana
authors.forename: M
authors.initials: M
authors.lastname: Selmi