title: Pd(I) phosphine carbonyl and hydride complexes implicated in the palladium-catalyzed oxo process.
abstract: Reduction of compound "Pd(bcope)(OTf)2" [bcope = (c-C8H14-1,5)PCH2CH2P(c-C8H14-1,5); OTf = O3SCF3] with H2/CO yields a mixture of Pd(I) compounds [Pd2(bcope)2(CO)2](OTf)2 (1) and [Pd2(bcope)2(mu-CO)(mu-H)](OTf) (2), whereas reduction with H2 or Ph3SiH in the absence of CO leads to [Pd3(bcope)3(mu3-H)2](OTf)2 (3). Exposure of 3 to CO leads to 1 and 2. The structures of 1 and 3 have been determined by X-ray diffraction. Complex [Pd2(bcope)2(CO)2](2+) displays a metal-metal bonded structure with a square planar environment for the Pd atoms and terminally bonded CO ligands and is fluxional in solution. DFT calculations aid the interpretation of this fluxional behavior as resulting from an intramolecular exchange of the two inequivalent P atom positions via a symmetric bis-CO-bridged intermediate. A cyclic voltammetric investigation reveals a very complex redox behavior for the "Pd(bcope)(OTf)2"/CO system and suggests possible pathways leading to the formation of the various observed products, as well as their relationship with the active species of the PdL2(2+)/CO/H2-catalyzed oxo processes (L2 = diphosphine ligands).
authors.affiliation: Laboratoire de Chimie de Coordination, UPR CNRS 8241 liée par convention à l'Université Paul Sabatier et à l'Institut National Polytechnique de Toulouse, 205 Route de Narbonne, 31077 Toulouse Cedex, France.
authors.forename: Miguel
authors.initials: M
authors.lastname: Baya
authors.forename: Jennifer
authors.initials: J
authors.lastname: Houghton
authors.forename: Denes
authors.initials: D
authors.lastname: Konya
authors.forename: Yohan
authors.initials: Y
authors.lastname: Champouret
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Daran
authors.forename: Karina Q
authors.initials: KQ
authors.lastname: Almeida Leñero
authors.forename: Lodewijk
authors.initials: L
authors.lastname: Schoon
authors.forename: Wilhelmus P
authors.initials: WP
authors.lastname: Mul
authors.forename: A Bart
authors.initials: AB
authors.lastname: van Oort
authors.forename: Nicolaas
authors.initials: N
authors.lastname: Meijboom
authors.forename: Eite
authors.initials: E
authors.lastname: Drent
authors.forename: A Guy
authors.initials: AG
authors.lastname: Orpen
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Poli