Iridium(I) Complexes of π-Acidic Carboxamides

The silver salts of the conjugate bases of the nitrogen acids N-nitroacetamide (Ag[CH3C(O)NNO2] (1)), N-nitrocarbamate (Ag[R'OC(O)NNO2], R' = CH3 (2), C2H5 (3)), N-nitrosomethylcarbamate (Ag[CH3OC(O)NNO] (4)), and N-nitro-p-tolylsulfonamide, (Ag[p-tolylSO(2)NNO(2)] (5)) react with trans-Ir(Cl)(CO)(PPh3)(2) (Vaskas complex) to give trans-Ir(eta(1)-nitrogen acid)(CO)(PPh3)(2) complexes (6-10). The related silver amides dinitramide and bistriflimide also react with trans-Ir(Cl)(CO)(PPh3)(2), to give trans-Ir[eta(1)-N(NO2)(2)](CO)(PPh3)(2) (11) and the unusual silver adduct [trans-Ir(Cl)(CO)(PPh3)(2)][Ag[N(SO2CF3)(2)]] (12), respectively. The reaction of trimethylsilyl bistriflimide, prepared in situ from trimethylsilyl bromide and Ag[N(SO2CF3)(2)] in acetonitrile, and Ir(F)(CO)(PPh3)(2) gives [trans-Ir(CH3CN)(CO)-(PPh3)(2)][N(SO2CF3)(3)] (13). The molecular structures of these complexes are all square planar, with the exception of 12, which is square pyramidal with the AgX ligand in the apical position. Complexes 6-9, 12, and 13 are stable to air in solution, while 10 and 11 are reactive toward oxygen.