Molecular Structure of Nitro- and Nitrito-Copper Complexes as Reaction Intermediates in Electrochemical Reduction of Nitrite to Dinitrogen Oxide

Article abstract of DOI:10.1246/bcsj.68.581

Copper-nitrito and -nitro isomers, PF6 and PF6 (tpa = tris<(2-pyridyl)methyl>amine) were isolated and the molecular structures were determined by X-ray analysis. PF6 (C18H18N5O2PF6Cu) crystallizes in the monoclinic space group P2₁/a with a = 13.374(2), b = 14.033(2), c = 13.455(2) Angstroem, β = 119.10(1) deg, V = 2206.5(6) Angstroem³, and Z = 4. a = 16.718(3), b = 17.554(3), c = 14.785(3) Angstroem, V = 4338(1) Angstroem³, and Z = 8.Those nitrito- and nitro-complexes exist as an equilibrium mixture in solutions.Electrochemical reduction of NO2^- in the presence of (ClO4)2 at -0.4 V in H2O (pH 7.0) catalytically produced N2O with concomitant evolution of a small amount of NO via the nitro and nitrito adducts.