title: Reactions of Co(III)-nitrosyl complexes with superoxide and their mechanistic insights.
abstract: New Co(III)-nitrosyl complexes bearing N-tetramethylated cyclam (TMC) ligands, [(12-TMC)Co(III)(NO)](2+) (1) and [(13-TMC)Co(III)(NO)](2+) (2), were synthesized via [(TMC)Co(II)(CH3CN)](2+) + NO(g) reactions. Spectroscopic and structural characterization showed that these compounds bind the nitrosyl moiety in a bent end-on fashion. Complexes 1 and 2 reacted with KO2/2.2.2-cryptand to produce [(12-TMC)Co(II)(NO2)](+) (3) and [(13-TMC)Co(II)(NO2)](+) (4), respectively; these possess O,O'-chelated nitrito ligands. Mechanistic studies using (18)O-labeled superoxide ((18)O2(•-)) showed that one O atom in the nitrito ligand is derived from superoxide and the O2 produced comes from the other superoxide O atom. Evidence supporting the formation of a Co-peroxynitrite intermediate is also presented.
authors: †Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
authors: Pankaj
authors: P
authors: Kumar
authors: †Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
authors: Yong-Min
authors: YM
authors: Lee
authors: †Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
authors: Young Jun
authors: YJ
authors: Park
authors: ‡Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States.
authors: Maxime A
authors: MA
authors: Siegler
authors: ‡Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States.
authors: Kenneth D
authors: KD
authors: Karlin
authors: †Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
authors: Wonwoo
authors: W
authors: Nam
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009589:Nitrogen Oxides / Q000737:chemistry*; D013481:Superoxides / Q000737:chemistry*
chemical_list: D009589:Nitrogen Oxides; D013481:Superoxides; D003035:Cobalt