Abstract: Three conformations of [M(CO)3(PPh2py)2] (M=Fe, Ru), HH conformation representing that both P atoms on the PPh2py coordinated to M, HT conformation representing that P and N atoms on two different PPh2py coordinated to M, and HH’ representing that two N atoms coordinated to M, were calculated by means of density functional theory (DFT) PBE0 method. The conclusions were drawn as follows: (1) The largest contribution of P atom in PPh2py to HOMO orbital indicated that P atomin PPh2py was easier to coordinate to metal atom as an electron donor thanNatom. (2) The HHconformation was the most stable one, while HH’ was the most unstable according to molecular energies and interaction energies. This conclusion consisted with the result of synthesis experiment, in which the HH conformation products had always been gotten. (3) P—Mbonds were stronger thanN—Mbonds by a comparison of their bond lengths and bond indices. There was a σ bond between P and Matoms, while in the case of interaction between N andMatoms, there was only a weak charge transfer between them (nN→n*M or nN→σ*M-P ). (4) The largest negative charge and contribution of metal atom in the HH conformation to HOMO orbital indicated that the HH conformation was the easiest to coordinate to a second metal atom and forma binuclear complex withMas the electron donor.

Key words: DFT(PBE0), NBO, 2-(Diphenylphosphino)pyridine, Organic metal complex, Stability