title: An iridium-mediated C-H activation/CO2-carboxylation reaction of 1,1-bisdiphenylphosphinomethane.
abstract: The reaction of 1,1-bisdiphenylphosphinomethane (dppm, 4 eq.) with [IrCl(coe)(2)](2) results in a solvent dependent equilibrium from which the complexes [IrCl(dppm)(dppm-H)(H)] (1) and [Ir(dppm)(2)]Cl (2) were isolated. When 2 is dissolved in methanol, [IrCl(dppm)(2)(H)][OCH(3)] (4) is formed as dominant species in solution. The C-H activation reaction which leads to 1 and 4 can be suppressed by adding an additional dppm ligand per iridium center resulting in the formation of [Ir(dppm)(3)]Cl (5). If the reaction of dppm with [IrX(coe)(2)](2) (X = Cl, I) is performed under an atmosphere of CO(2) the complexes [IrX(dppm)(H){(Ph(2)P)(2)C-COOH}] (6: X = Cl; 7: X = I) are formed by a CH activation/CO(2) carboxylation sequence. The reaction of 6 with NH(4)PF yields [IrCl(dppm)(2)(H)]PF(6).(10). Additionally the lithium compounds [Li(dme)(2)(dppm-H)] (3) and [Li(dme){(Ph(2)P)(2)CHCOO}](2) (8) were prepared for comparison. The molecular structures of the compounds 1, 3, 5, 7, 8 and of the related iridium complex [IrCl(dppm)(2)(H)]I (11) are reported.
authors.affiliation: Institute of Inorganic and Analytical Chemistry, Friedrich-Schiller-University Jena, August-Bebel-Str. 2, 07743, Jena, Germany. j.langer@uni-jena.de
authors.forename: Jens
authors.initials: J
authors.lastname: Langer
authors.forename: María José
authors.initials: MJ
authors.lastname: Fabra
authors.forename: Pilar
authors.initials: P
authors.lastname: García-Orduña
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Lahoz
authors.forename: Helmar
authors.initials: H
authors.lastname: Görls
authors.forename: Luis A
authors.initials: LA
authors.lastname: Oro
authors.forename: Matthias
authors.initials: M
authors.lastname: Westerhausen