Synthesis and characterization of [Co(NO2)2(acac)(IMH2py)] with one-electron-reduced imino nitroxide radical associated with unusual displacement of acetylacetonate in the starting complex trans-Na[Co(NO2)2(acac)2]

A reaction of trans-Na[Co(NO2)2(acac)2] with IM2py(2(2′-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl) in methanol afforded trans-[Co(NO2)2(acac)(IMH2py)](IMH2py=1-hydroxyl-2(2′-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole); one-electron reduction of the N–O radical moiety in IM2py and displacement of one of the two acac ligands with retention of two nitrito ligands in the starting complex during the reaction. This new complex was characterized by UV–Vis, 1H NMR spectra and X-ray analysis.