title: Methyl-, Ethenyl-, and Ethynyl-Bridged Cationic Digold Complexes Stabilized by Coordination to a Bulky Terphenylphosphine Ligand.
abstract: Reactions of the gold(I) triflimide complex [Au(NTf2 )(PMe2 Ar${{^{{\rm Dipp}{_{2}}}}}$)] (1) with the gold(I) hydrocarbyl species [AuR(PMe2 Ar${{^{{\rm Dipp}{_{2}}}}}$)] (2 a-2 c) enable the isolation of hydrocarbyl-bridged cationic digold complexes with the general composition [Au2 (μ-R)(PMe2 Ar${{^{{\rm Dipp}{_{2}}}}}$)2 ][NTf2 ], where Ar${{^{{\rm Dipp}{_{2}}}}}$=C6 H3 -2,6-(C6 H3 -2,6-iPr2 )2 and R=Me (3), CHCH2 (4), or CCH (5). Compound 3 is the first alkyl-bridged digold complex to be reported and features a symmetric [Au(μ-CH3 )Au](+) core. Complexes 4 and 5 are the first species of their kind that contain simple, unsubstituted vinyl and acetylide units, respectively. In the series of complexes 3-5, the bridging carbon atom systematically changes its hybridization from sp(3) to sp(2) and sp. Concomitant with this change, and owing to variations in the nature of the bonding within the [Au(μ-R)Au](+) unit, there is a gradual decrease in aurophilicity, that is, the strength of the Au⋅⋅⋅Au bonding interaction decreases. This change is illustrated by a monotonic increase in the Au-Au distance by approximately 0.3 Å from R=CH3 (2.71 Å) to CHCH2 (3.07 Å) and CCH (3.31 Å).
authors.affiliation: Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and, Universidad de Sevilla, Avda. Américo Vespucio, 49, 41092 Sevilla (Spain).
authors.forename: María F
authors.initials: MF
authors.lastname: Espada
authors.affiliation: Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and, Universidad de Sevilla, Avda. Américo Vespucio, 49, 41092 Sevilla (Spain). jesus.camposmanzano@iiq.cisc.es.|Present address: Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR (UK). jesus.camposmanzano@iiq.cisc.es.
authors.forename: Jesús
authors.initials: J
authors.lastname: Campos
authors.affiliation: Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and, Universidad de Sevilla, Avda. Américo Vespucio, 49, 41092 Sevilla (Spain).
authors.forename: Joaquín
authors.initials: J
authors.lastname: López-Serrano
authors.affiliation: Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and, Universidad de Sevilla, Avda. Américo Vespucio, 49, 41092 Sevilla (Spain).
authors.forename: Manuel L
authors.initials: ML
authors.lastname: Poveda
authors.affiliation: Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and, Universidad de Sevilla, Avda. Américo Vespucio, 49, 41092 Sevilla (Spain). guzman@us.es.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Carmona
keywords: aurophilicity; bridging ligands; density functional calculations; gold; phosphines