title: Geometric and electronic structure and reactivity of a mononuclear "side-on" nickel(III)-peroxo complex.
abstract: Metal-dioxygen adducts, such as metal-superoxo and -peroxo species, are key intermediates often detected in the catalytic cycles of dioxygen activation by metalloenzymes and biomimetic compounds. The synthesis and spectroscopic characterization of an end-on nickel(II)-superoxo complex with a 14-membered macrocyclic ligand was reported previously. Here we report the isolation, spectroscopic characterization, and high-resolution crystal structure of a mononuclear side-on nickel(III)-peroxo complex with a 12-membered macrocyclic ligand, [Ni(12-TMC)(O(2))](+) (1) (12-TMC = 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane). Different from the end-on Ni(II)-superoxo complex, the Ni(III)-peroxo complex is not reactive in electrophilic reactions, but is capable of conducting nucleophilic reactions. The Ni(III)-peroxo complex transfers the bound dioxygen to manganese(II) complexes, thus affording the corresponding nickel(II) and manganese(III)-peroxo complexes. The present results demonstrate the significance of supporting ligands in tuning the geometric and electronic structures and reactivities of metal-O(2) intermediates that have been shown to have biological as well as synthetic usefulness in biomimetic reactions.
authors: Department of Chemistry and Nano Science, Center for Biomimetic Systems, Ewha Womans University, Seoul, Korea.
authors: Jaeheung
authors: J
authors: Cho
authors: Ritimukta
authors: R
authors: Sarangi
authors: Jamespandi
authors: J
authors: Annaraj
authors: Sung Yeon
authors: SY
authors: Kim
authors: Minoru
authors: M
authors: Kubo
authors: Takashi
authors: T
authors: Ogura
authors: Edward I
authors: EI
authors: Solomon
authors: Wonwoo
authors: W
authors: Nam
mesh_terms: D018360:Crystallography, X-Ray; D004583:Electrons; D008024:Ligands; D047028:Macrocyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D008345:Manganese / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D008024:Ligands; D047028:Macrocyclic Compounds; D009942:Organometallic Compounds; D008345:Manganese; D009532:Nickel; D010100:Oxygen