Reactions of Co(III) - Nitrosyl Complexes with Superoxide and Their Mechanistic Insights

Pankaj Kumar; Yong Min Lee; Young Jun Park; Maxime A. Siegler; Kenneth D. Karlin; Wonwoo Nam

doi:10.1021/ja513234b

Reactions of Co(III) - Nitrosyl Complexes with Superoxide and Their Mechanistic Insights

Pankaj Kumar, Yong Min Lee, Young Jun Park, Maxime A. Siegler, Kenneth D. Karlin, Wonwoo Nam

Department of Chemistry & Nanoscience

Research output: Contribution to journal › Article › peer-review

38 Scopus citations

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 ¹⁸O-labeled superoxide (¹⁸O₂^•-) 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.

Original language	English
Pages (from-to)	4284-4287
Number of pages	4
Journal	Journal of the American Chemical Society
Volume	137
Issue number	13
DOIs	https://doi.org/10.1021/ja513234b
State	Published - 8 Apr 2015

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© 2015 American Chemical Society.

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@article{225eb10ceeb64c8580f5dc167b2e9875,

title = "Reactions of Co(III) - Nitrosyl Complexes with Superoxide and Their Mechanistic Insights",

abstract = "New CoIII-nitrosyl complexes bearing N-tetramethylated cyclam (TMC) ligands, [(12-TMC)CoIII(NO)]2+ (1) and [(13-TMC)CoIII(NO)]2+ (2), were synthesized via [(TMC)CoII(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)CoII(NO2)]+ (3) and [(13-TMC)CoII(NO2)]+ (4), respectively; these possess O,O′-chelated nitrito ligands. Mechanistic studies using 18O-labeled superoxide (18O2•-) 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.",

author = "Pankaj Kumar and Lee, {Yong Min} and Park, {Young Jun} and Siegler, {Maxime A.} and Karlin, {Kenneth D.} and Wonwoo Nam",

note = "Publisher Copyright: {\textcopyright} 2015 American Chemical Society.",

year = "2015",

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doi = "10.1021/ja513234b",

language = "English",

volume = "137",

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T1 - Reactions of Co(III) - Nitrosyl Complexes with Superoxide and Their Mechanistic Insights

AU - Kumar, Pankaj

AU - Lee, Yong Min

AU - Park, Young Jun

AU - Siegler, Maxime A.

AU - Karlin, Kenneth D.

AU - Nam, Wonwoo

PY - 2015/4/8

Y1 - 2015/4/8

N2 - New CoIII-nitrosyl complexes bearing N-tetramethylated cyclam (TMC) ligands, [(12-TMC)CoIII(NO)]2+ (1) and [(13-TMC)CoIII(NO)]2+ (2), were synthesized via [(TMC)CoII(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)CoII(NO2)]+ (3) and [(13-TMC)CoII(NO2)]+ (4), respectively; these possess O,O′-chelated nitrito ligands. Mechanistic studies using 18O-labeled superoxide (18O2•-) 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.

AB - New CoIII-nitrosyl complexes bearing N-tetramethylated cyclam (TMC) ligands, [(12-TMC)CoIII(NO)]2+ (1) and [(13-TMC)CoIII(NO)]2+ (2), were synthesized via [(TMC)CoII(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)CoII(NO2)]+ (3) and [(13-TMC)CoII(NO2)]+ (4), respectively; these possess O,O′-chelated nitrito ligands. Mechanistic studies using 18O-labeled superoxide (18O2•-) 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.

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JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

IS - 13

ER -

Reactions of Co(III) - Nitrosyl Complexes with Superoxide and Their Mechanistic Insights

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