Cytochrome <i>c</i> nitrite reductase catalyzes the six-electron, eight-proton reduction of nitrite to ammonium as part of the global nitrogen cycle. Here, a new electrocatalyst mimicking this reactivity is reported. This small cobalt-peptide (Gly-Gly-His) complex (CoGGH) has an onset potential for nitrite reduction at -0.65 V vs Ag/AgCl (1M KCl) at pH 7.2. The effect of pH on catalytic potential is consistent with a proton-coupled electron transfer process as part of the mechanism. Controlled potential electrolysis at -0.90 V vs Ag/AgCl (1M KCl) at pH 7.2 generates ammonium with a faradaic efficiency of 94% and a turnover number of 3,520 over 5 hours. CoGGH also catalyzes the reduction of proposed intermediates nitric oxide and hydroxylamine to ammonium. Ongoing efforts to elucidate catalytic mechanism and to understand the relationship between catalyst structure and function will be presented.

A metallopeptide functional mimic of cytochrome <i>c</i> nitrite reductase

255th National Meeting (2018)

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A metallopeptide functional mimic of cytochrome c nitrite reductase