Synthesis and crystal structure of Ir(C2H4)2(C5H7O2)

We report a new synthesis and characterization of Ir(C2H4)(2)(C5H7O2) [(acetylacetonato)-bis(eta(2)-ethene)iridium(l)], prepared from (NH4)(3)IrCl6 center dot H2O in a yield of about 45%. The compound has been characterized by X-ray diffraction crystallography, infrared, Raman, and NMR spectroscopies and calculations at the level of density functional theory. Ir(C2H4)(2)(C5H7O2) is isostructural with Rh(C2H4)(2)(C5H7O2), but there is a substantial difference in the ethylene binding energies, with Ir-ethylene having a stronger interaction than Rh-ethylene; two ethylenes are bound to Ir with a binding energy of 94 kcal/mol and to Rh with a binding energy of 70 kcal/mol. (C) 2007 Elsevier B.V. All rights reserved.