Preferential geometry and reactivity of neutral iridium(III) and rhodium(III) complexes bearing a flexible heterochelate pn ligand (PN = o -Ph2PC6H4CH2OCH2C5H4N -2)

Reactions of [IrCl(coe)2]2 (coe = cyclooctene) with 1 equiv of the PN ligand (PN = o-Ph2PC6H4CH2OCH2C5H4N-2) in the presence of several phosphines or pyridine (1 equiv) at room temperature afforded a neutral iridium(III) hydride complex, (PCN-κ3P,C,N)Ir(H)(Cl)(L) (PCN = Ph2PC6H4CHOCH2C5H4N) [L = PPh3 (1a), PCy3 (1b), PBu3 (1c), PMePh2 (1d), Py (1e)] in good isolated yield. The PCN ligand is coordinated in a meridional manner, which was confirmed by spectral analyses and X-ray analysis of 1a. The related rhodium(III) hydride complex (PCN-κ3P,C,N)Rh(H)(Cl)(L) (PCN = Ph2PC6H4CHOCH2C5H4N) [L = PPh3 (4a), PCy3 (4b)] was also prepared from the reactions of [RhCl(coe)2]2 with 1 equiv of the PN ligand in the presence of 1 equiv of PPh3 or PCy3. The structure of 4a and 4b was determined by spectral analyses and X-ray analysis of 4a. In contrast to the iridium complexes, the PCN ligand in the rhodium(III) complexes coordinated to the metal center in a facial manner. A ligand exchange reaction of the PPh3 iridium(II...