Ligand vs. Metal Basicity: Reactions of 2-(Diphenylphosphanyl)anilido and 2-(Diphenylphosphanyl)phenolato Complexes of Rhodium(I) and Iridium(I) with HBF4

Abstract

Treatment of [M(CO)(PPh3)(2-Ph2PC6H4NR-κN,κP)], where M/NR = Rh/NH (1), Rh/NCH3 (2), Ir/NH (3), and Ir/NCH3 (4), with Et2O・HBF4 in CH2Cl2 resulted in protonation at nitrogen with formation of [M(CO)(PPh3)(2-Ph2PC6H4NHR-κN,κP)]BF4 [M/NHR = Rh/NH2 (7), Rh/NHCH3 (8), Ir/NH2 (9), Ir/NHCH3 (10)]. Similar protonation of [Rh(CO)(PPh3)(2-Ph2PC6H4O-κO,κP)] (5) in CH2Cl2 afforded [Rh(CO)(PPh3)(2-Ph2PC6H4OH-κO,κP)]BF4 (11), but furnished [Rh(CO)(PPh3)- (NCCH3)(2-Ph2PC6H4OH-κP)]BF4 (12) if carried out in CH3CN. [Ir(CO)(PPh3)(2-Ph2PC6H4O- κO,κP)] (6) reacted with HBF4 by protonation at the central metal atom and oxidative addition to give [IrH(FBF3)(CO)(PPh3)(2-Ph2PC6H4O-κO,κP)] (13), the substitutionally labile BF4 − ligand of which underwent smooth exchange with neutral donors L producing [IrH(CO)(L)(PPh3)(2- Ph2PC6H4O-κO,κP)]BF4 with L = H2O (14), CH3CN (15) and PPh3 (16). The structures of 6 and 15 were determined by single-crystal X-ray crystallography.