Coordination Chemistry of Functional Phosphanes, VI. Rhodium and Iridium Complexes with 2‐(Diphenylphosphophanyl)phenylamido Ligands

Treatment of trans ‐[MCl(CO)(PPH 3 ) 2 ] (M = Rh, Ir) with the lithium salts fof the bidentate hybride ligands 2‐Ph 2 PC 6 H 4 N(R)H [‘PN(R)H’ R = H, Me] produced the chelate complexes [M(CO)(PPH 3 )(‘PNR’)] [M/NR = Rh/NH ( 1a ), Ir/ NH ( 2a ), Rh/NMe ( 1b ), Ir/NMe ( 2b )] containing the CO ligand and the NR substituent in mutual trans ‐arrangement. 2b was shown by single‐crystal X‐ray diffraction to possess an amido‐nitrogen atom in a trigonal‐planar environment. Oxidative addition of H 2 to 2b reversibly formed cis ‐[IrH 2 (CO)(PPh 3 )(‘PNMe’)] ( 3 ), in which H 2 has added perpendicular to the N–Ir–CO axis. While both 1a,b and 2a, b proved to the completely unreactive toward CO 2 at ambient temperature and pressure, reactions of 1a and 2a/b with sulfur dioxide reversibly formed pentacoordinate SO 2 adducts, [M(SO 2 )(CO(PPh 3 )(‘PNR’)][M/NR = Rh/Nh ( 4a ), Ir/NH ( 5a ), Ir/NMe ( 5b ) with M–S‐bonded pyramidal MSO 2 units as established by an X‐ray structure analysis of 5a . Complex 5b reacted with dioxygen to form the sulfato compound [Ir(O 2 SO 2 )(CO)(‘PNMe’)] ( 6 ). Combination of 2a with HCl in CHCl 3 at −60°C resulted in protonation of both the iridium and the nitrogen atom to give an ionic chelate complex, [IrHCl(CO)(PPh 3 )(‘PNH 2 ’)]Cl ( 7 ), containing one of its NH groups hydrogen‐bonded to Ir–Cl. Ring opening of the chelate structure with formation of [IrHCl 2 (CO)(PPh 3 )(PPh 2 C 6 H 4 N(Me)H‐ o )] ( 8 ) was observed in the analogous reaction of 2b with hydrogen chloride. NMR spectroscopy showed 8 to exist in CDCl 3 solution as a mixture of three Ir–PPh 2 C 6 H 4 N(Me)H‐ o rotamers, stabilized by intramolecular –N(Me)H —ClIr hydrogen bonding.