title: Synthesis, Molecular Structure, and Vibrational Spectra of mer-Tris(carbonyl)iridium(III) Fluorosulfate, mer-Ir(CO)(3)(SO(3)F)(3).
abstract: Addition of carbon monoxide (0.5-2 atm) to iridium(III) fluorosulfate, Ir(SO(3)F)(3), dissolved in HSO(3)F over 4 days and at 60 degrees C, results in the quantitative formation of tris(carbonyl)iridium(III) fluorosulfate Ir(CO)(3)(SO(3)F)(3). Slow evaporation of the solvent produces single crystals of mer-Ir(CO)(3)(SO(3)F)(3). Crystal structure data for mer-Ir(CO)(3)(SO(3)F)(3): monoclinic, space group P2(1)/c, Z = 4, a = 8.476(1) Å, b = 12.868(2) Å, c = 12.588 (1) Å, beta = 108.24(1) degrees, V = 1304.0 Å(3), T = 200 K, R(F)() = 0.022 for 2090 data (I(o) >/= 2.5sigma(I(o))) and 200 variables. Vibrational spectra of the crystalline solid are consistent with a mer-isomer with CO stretching modes at 2249 (A(1)), 2208 (B(1)), and 2198 (A(1)) cm(-)(1) in the IR spectrum. In solution of HSO(3)F, additional CO stretching bands attributed to the fac-isomer are found in the FT-Raman and IR spectra at 2233 (A(1)) and 2157 cm(-)(1) (E). Additional evidence for a mixture of fac- and mer-isomers comes from (19)F NMR spectra. The vibrational spectra suggest strongly reduced iridium to CO pi-back-bonding. The crystal structure reveals significant intra- and intermolecular contacts between the electropositive C atom of the CO groups and O or F atoms of the fluorosulfate groups. Hence mer-tris(carbonyl)iridium(III) fluorosulfate becomes the first thermally stable, structurally characterized, and predominantly sigma-bonded carbonyl derivative of a metal in the +3 oxidation state.
authors.affiliation: Department of Chemistry, The University of British Columbia, Vancouver, BC, Canada V6T 1Z1, Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada V5A 1S6, and Institut für Anorganische Chemie der Universität, D-30167 Hannover, Callinstrasse 9, Germany.
authors.forename: Changqing
authors.initials: C
authors.lastname: Wang
authors.forename: Andrew R.
authors.initials: AR
authors.lastname: Lewis
authors.forename: Raymond J.
authors.initials: RJ
authors.lastname: Batchelor
authors.forename: Frederick W. B.
authors.initials: FW
authors.lastname: Einstein
authors.forename: Helge
authors.initials: H
authors.lastname: Willner
authors.forename: Friedhelm
authors.initials: F
authors.lastname: Aubke