Self‐Assembly of a Mixed‐Valent Co32 Ring

Solvothermal reaction of CoCl2·6H2O with H3tci [H3tci = tris(2-carboxyethyl)isocyanurate] in H2O/CH3COCH3 in the presence of triethylamine gave rise to a mixed-valent thirty-two nuclear cobalt cluster, namely, [CoII16CoIII16(μ4-O)16(tci)16(H2O)12]·40H2O (1). Crystal structural analysis showed that four octanuclear [CoII4CoIII4(μ4-O)4]12+ units were bridged by the carbonyl oxygen atoms of the tci3– ligands to give a Co32 ring. Magnetic studies confirmed the paramagnetic nature of this cluster, and cyclic voltammetry showed an irreversible oxidation at 1.0 V versus saturated calomel electrode.