Characterization of Iminobismuthanes and Catalytic Reduction of Organic Azides via Bi(I)/Bi(III) Redox Cycling

We report the stoichiometric and catalytic reactivity of organobismuth(I) complexes with organic azides. Treatment of N,C,N-pincer bismuthinidenes with organic azides (acyl, sulfonyl, and bulky aryl) results in monomeric iminobismuthanes which can be structurally characterized -including the formal Bi=N double bond- by multinuclear NMR spectroscopy and single-crystal X-ray diffraction. Building upon the stoichiometric reactivity of the monomeric iminobismuthanes, catalytic reduction of a broad range of organic azides is developed. DFT calculations of the catalytic reaction pathway support the redox nature of the overall process.