Catalytic Ammonia Oxidation to Dinitrogen by a Nickel Complex |
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| Authors: | David N Stephens Prof Robert K Szilagyi Paige N Roehling Dr Navamoney Arulsamy Prof Michael T Mock |
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| Institution: | 1. Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717 USA;2. Department of Chemistry, University of British Columbia - Okanagan, Kelowna, British Columbia Canada;3. Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071 USA |
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| Abstract: | We report a nickel complex for catalytic oxidation of ammonia to dinitrogen under ambient conditions. Using the aryloxyl radical 2,4,6-tri-tert-butylphenoxyl (tBu3ArO⋅) as a H atom acceptor to cleave the N−H bond of a coordinated NH3 ligand up to 56 equiv of N2 per Ni center can be generated. Employing the N-oxyl radical 2,2,6,6-(tetramethylpiperidin-1-yl)oxyl (TEMPO⋅) as the H-atom acceptor, up to 15 equiv of N2 per Ni center are formed. A bridging Ni-hydrazine product identified by isotopic nitrogen (15N) studies and supported by computational models indicates the N−N bond forming step occurs by bimetallic homocoupling of two paramagnetic Ni]−NH2 fragments. Ni-mediated hydrazine disproportionation to N2 and NH3 completes the catalytic cycle. |
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| Keywords: | Ammonia Oxidation Dinitrogen Hydrogen Atom Abstraction Molecular Catalyst Nickel |
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