title: Synthesis and characterization of Ni(III)N3S2 complexes as active site models for the oxidized form of nickel superoxide dismutase.
abstract: Nickel complexes, [Ni(H2BA(R)TPP)](ClO4)2 (R = Ph for 1 or iPr for 2), supported by a pentadentate ligand H2BA(R)TPP were synthesized and oxidized to form Ni(III) species having a N3S2 coordination environment to mimic the active site of the oxidized form of nickel superoxide dismutase (NiSODox). The Ni(III) species 2(+) exhibited a rhombic signal with g values at 2.15, 2.12 and 2.02 similar to that of NiSODox. DFT calculations revealed that 2(+) has an unpaired electron primarily located in the dz2 orbital of the Ni(III) center, which strongly overlaps with the pz orbital of the axial pyridine nitrogen of H2BA(Pr)TPP.
authors.affiliation: Department of Chemistry, National Taiwan Normal University, 88, Sec. 4, Ting-Chow Rd., 11677 Taipei (Taiwan).
authors.forename: Chien-Wei
authors.initials: CW
authors.lastname: Chiang
authors.forename: Yun-Li
authors.initials: YL
authors.lastname: Chu
authors.forename: Hong-Ling
authors.initials: HL
authors.lastname: Chen
authors.forename: Ting-Shen
authors.initials: TS
authors.lastname: Kuo
authors.forename: Way-Zen
authors.initials: WZ
authors.lastname: Lee
mesh_terms: D020134:Catalytic Domain; D008958:Models, Molecular; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D010084:Oxidation-Reduction; D013482:Superoxide Dismutase / Q000378:metabolism*
chemical_list: D009532:Nickel; D013482:Superoxide Dismutase
keywords: biomimetics; catalysis; density functional calculations; nickel(III) complexes; superoxide