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

We report a new synthesis and characterization of Ir(C2H4)2(C5H7O2) [(acetylacetonato)-bis(η2-ethene)iridium(I)], prepared from (NH4)3IrCl6 · 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.