Oxidative Addition of Water and Aliphatic Alcohols by IrCl(trialkylphosphine)<sub>3</sub>
作者:Ofer Blum、David Milstein
DOI:10.1021/ja012611c
日期:2002.9.1
Oxidative addition of aliphatic alcohols to (C8H14)IrCl(PMe3)(3) in benzene yields the cis-hydridoalkoxo products mer-cis-HIr(OR)Cl(PMe3)(3) (R = Me, Et, 1-pentyl, 2-propyl) The analogous hydroxo complex is prepared by oxidative addition of water in THF. The addition rate depends on the nature of the alcohol (methanol > 1-pentanol >> 2-propanol and methanol > water). The reaction is retarded in polar media but accelerated by protic cosolvents. Anionic ligand redistribution involving chloride and alkoxide (or hydroxide) competes with the oxidative addition reaction. A detailed kinetic study suggests that the 16-electron 10(PMe3)(3) is the species undergoing the oxidative addition, and mer-cis-HIr(OR)Cl(PMe3)(3) is the kinetic product. The reaction proceeds by a single-step nucleophilic attack of the metal on the O-H proton pi-Donation by chloride stabilizes the transition state and governs the stereochemical course of the reaction Protic solvent aggregation in the transition state in an apolar medium is suggested mer-cis-HIr(OH)Cl(PEt3)(3), obtained by water addition to IrCl(PEt3)(3), was crystallographically characterized, showing an unusual hydrophobic cage around the hydride ligand.
Aqueous Organometallic Chemistry of <i>mer</i>-Ir(H)<sub>2</sub>(PMe<sub>3</sub>)<sub>3</sub>X Complexes
作者:Joseph S. Merola、Trang Le Husebo、Kelly E. Matthews
DOI:10.1021/om300140f
日期:2012.5.28
A series of Ir(H)(2)(PMe3)(3)X compounds where X = various anionic ligancls has been synthesized. The most studied of this group with X = Cl has been characterized fully, including by X-ray crystallography. For X = Cl, PhCO2-, dissolution in water results in the establishment of the equilibrium Ir(H)(2)(PMe3)(3)X + H2O = [Ir(H)(2)(PMe3)(3)(H2O)]X-+(-), which is responsible for the reaction of these compounds with unsaturated organic compounds. Reactions between the dihydrides and alkynes in water as well as the thermodynamics of the aqueous equilibrium are discussed.