title: The stereospecific ligand exchange at a pseudo-benzylic T-4 iridium centre in planar-chiral cycloiridium (eta(6)-arene)tricarbonylchromium complexes.
abstract: The stereospecificity of ligand exchange at the Ir(III) centre of a cycloiridium arenetricarbonylchromium complex has been established experimentally by various analytical methods as well as by X-ray diffraction structural analysis and computational investigations. Two new cases of phenyl and methyl iridium(III) complexes have been prepared by reaction of (S(P)*,R(Ir)*-chlorido{2-[(tricarbonyl)(eta(6)-phenylene-kappaC(1'))chromium(0)]pyridine-kappaN}(pentamethylcyclopentadienyl)iridium(III) with PhMgBr and MeMgBr. The determining influence of electrostatic repulsion has been established by means of density functional theory at the Becke-Perdew/TZP(ZORA) level by using, among other means, energy partitioning analysis. It is also shown that the Cr(CO)(3) fragment is likely to ease the ionic cleavage of the Ir-Cl bond in chlorido cycloiridium tricarbonylchromium complexes in a way similar to that already established for the solvolysis of benzyl halide complexes, that is, through a direct interaction of the Cr(0) centre with the cationic Ir(III) centre.
authors.affiliation: Laboratoire de Synthèses métallo-induites, Institut de Chimie, CNRS, Université de Strasbourg, France. djukic@unistra.fr
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Djukic
authors.forename: Cédric
authors.initials: C
authors.lastname: Boulho
authors.forename: Dusan
authors.initials: D
authors.lastname: Sredojevic
authors.forename: Carla
authors.initials: C
authors.lastname: Scheeren
authors.forename: Snezana
authors.initials: S
authors.lastname: Zaric
authors.forename: Louis
authors.initials: L
authors.lastname: Ricard
authors.forename: Michel
authors.initials: M
authors.lastname: Pfeffer