title: Gold(I) Complexes of Ferrocenyl Polyphosphines: Aurophilic Gold Chloride Formation and Phosphine-Concerted Shuttling of a Dinuclear [ClAu···AuCl] Fragment.
abstract: A smart steric control of the metallocene backbone in bis- and poly(phosphino)ferrocene ligands favors intramolecular aurophilic interactions between [AuCl] fragments in polynuclear gold(I) complexes. We synthesized and characterized by multinuclear NMR and X-ray diffraction analysis mono-, di-, and polynuclear gold complexes of constrained ferrocenyl diphosphines, which bear either bulky tert-butyl groups or more flexible siloxane substituents at the cyclopentadienyl rings. The complexes meso-1,1'-bis(diphenylphosphino)-3,3'-di-tert-butylferrocene (4-m), rac-1,1'-bis[bis(5-methyl-2-furyl)phosphino]-3,3'-di-tert-butylferrocene (5-r), and rac-1,1'-bis(diphenylphosphino)-3,3'-bis[(tri-iso-propylsilyl)oxy]ferrocene (6-r) were used to form dinuclear gold complexes. Coordination of tert-butylated ferrocenyl phosphines generated aurophilic interactions in the corresponding dinuclear gold complexes, contrary to gold(I) complexes reported with 1,1'-bis(diphenylphosphino)ferrocene. The structurally related tetraphosphine 1,1',2,2'-tetrakis(diphenylphosphino)-4,4'-di-tert-butylferrocene (11) also gave access to mononuclear, dinuclear, and the original trinuclear gold chloride aurophilic complexes in which 14e-to 16e-gold centers coexist. In such complexes, nonbonded ("through-space")31P-31P' nuclear spin couplings were evidenced by high-resolution NMR. In these interactions nuclear spin information is transferred between the lone-pair electron of an uncoordinated phosphorus P and a phosphorus P' that is involved in a σ covalent bond Au-P'. The dinuclear aurophilic complex displayed a concerted shuttling of its [ClAu···AuCl] fragment between the four phosphorus donors of the tetraphosphine ligand. Thus, an aurophilic Au···Au bond, which is assumed to be a weak energy interaction, can be conserved within a dynamic shuttling process at high temperature involving an intramolecular coordination-decoordination process of digold(I) at phosphorus atoms.
authors.affiliation: Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB, UMR 6302, CNRS), Université de Bourgogne Franche-Comté , 9 Avenue Alain Savary, 21078 Dijon, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Rampazzi
authors.affiliation: Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB, UMR 6302, CNRS), Université de Bourgogne Franche-Comté , 9 Avenue Alain Savary, 21078 Dijon, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Roger
authors.affiliation: Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB, UMR 6302, CNRS), Université de Bourgogne Franche-Comté , 9 Avenue Alain Savary, 21078 Dijon, France.
authors.forename: Régine
authors.initials: R
authors.lastname: Amardeil
authors.affiliation: Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB, UMR 6302, CNRS), Université de Bourgogne Franche-Comté , 9 Avenue Alain Savary, 21078 Dijon, France.
authors.forename: Marie-José
authors.initials: MJ
authors.lastname: Penouilh
authors.affiliation: Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB, UMR 6302, CNRS), Université de Bourgogne Franche-Comté , 9 Avenue Alain Savary, 21078 Dijon, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Richard
authors.affiliation: Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB, UMR 6302, CNRS), Université de Bourgogne Franche-Comté , 9 Avenue Alain Savary, 21078 Dijon, France.
authors.forename: Paul
authors.initials: P
authors.lastname: Fleurat-Lessard
authors.affiliation: Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB, UMR 6302, CNRS), Université de Bourgogne Franche-Comté , 9 Avenue Alain Savary, 21078 Dijon, France.|Institut Universitaire de France (IUF) , 103 Boulevard Saint Michel, 75005 Paris Cedex, France.
authors.forename: Jean-Cyrille
authors.initials: JC
authors.lastname: Hierso