Activation of nitrogen bronsted acids: Synthesis and reactivity of a new class of nitrogen acid complexes

Article abstract of DOI:10.1021/ic5017033

The nitrogen acids RC(O)NHNO₂, N-nitroamide, R = CH₃ (1), C₂H₅ (2) and N-nitrocarbamate, R′OC(O)NHNO₂, R′ = CH₃ (3), C₂H₅ (4) are a class of primary N-nitrocarboxamide compounds that oxidatively add to trans-Ir^(I)(Cl)(N₂)(PPh₃)₂ to give six-coordinate Ir^(III)(η²-(NO₂)-nitrogen acid)(H)(Cl)(PPh₃)₂ complexes 5-8. Unexpected fluxional behavior of the complexes in solution is observed by ¹H NMR spectroscopy. Reaction intermediates of the oxidative addition reactions were also observed and monitored using ³¹P and ¹H NMR and solution IR spectroscopies. Complex 5 reacts with methyl triflate in CH₃CN to generate bis(acetonitrile) complex (9) from a net loss of the nitrogen acid anion. P(CH₃)₂Ph reacts with 5 to give phosphine-substituted and P(CH₃)₂Ph addition isomers (10). Reactivity studies of 5 with CO gave metastable CO adduct isomer 11, which loses CO on prolonged standing in solution. (Chemical Equation Presented).