文摘
One-electron-oxidized NiIII-phenoxide complexes with salen-type ligands, [Ni(salen)py2]2+ ([1en-py]2+) and [Ni(1,2-salcn)py2]2+ ([1cn-py]2+), with a five-membered chelate dinitrogen backbone and [Ni(salpn)py2]2+ ([2pn-py]2+), with a six-membered chelate backbone, have been characterized with a combination of experimental and theoretical methods. The five-membered chelate complexes [1en-py]2+ and [1cn-py]2+ were assigned as NiIII-phenoxyl radical species, while the six-membered chelate complex [2pn-py]2+ was concluded to be a NiII-bis(phenoxyl radical) species with metal-centered reduction in the course of the one-electron oxidation of the NiIII-phenoxide complex [2pn-py]+. Thus, the oxidation state of the one-electron-oxidized NiIII salen-type complexes depends on the chelate ring size of the dinitrogen backbone.