Donor Properties of a Series of Two-Electron Ligands

A large group of two-electron donor ligands were compared and ranked with the help of DFT calculations. The following characteristics were considered: (a) C O stretching frequencies and distances of Ni(CO)(3)L, IrCl(CO)(2)L, and IrCp(CO)L, (b) Ir-(eta(2)-C2H4) bond enthalpies, stretching frequencies, and distances of IrCp(eta(2)-H2C=CH2)L, (c) enthalpies of. the ligand exchange reactions IrCp(CO)L + IrCpXe(PF3) -> IrCp(CO)(PF3) + IrCpXeL and (IrH2CpL)-H-(III) + (IrCpXe)-Cp-(I)(PF3) -> (IrH2CP)-H-(III)(PF3) + (IrCpXeL)-Cp-(I), (d) Ir-(eta(2)-H-2) bond enthalpies and H-H distances of Os(eta(2)-H-2)Cl-2(CO)L-2. Useful trends and correlations have been established for several common ligand types.