Photoinitiated Reactivity of a Thiolate-Ligated, Spin-Crossover Nonheme {FeNO}(7) Complex with Dioxygen.

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Details zur Publikation

Autorinnen und Autoren: Mc Quilken AC, Matsumura H, Dürr M, Confer AM, Sheckelton JP, Siegler MA, Mc Queen TM, Ivanovic-Burmazovic I, Moenne-Loccoz P, Goldberg DP
Zeitschrift: Journal of the American Chemical Society
Verlag: American Chemical Society
Jahr der Veröffentlichung: 2016
Band: 138
Heftnummer: 9
Seitenbereich: 3107-17
ISSN: 1520-5126


Abstract


The nonheme iron complex, [Fe(NO)(N3PyS)]BF4, is a rare example of an {FeNO}(7) species that exhibits spin-crossover behavior. The comparison of X-ray crystallographic studies at low and high temperatures and variable-temperature magnetic susceptibility measurements show that a low-spin S = 1/2 ground state is populated at 0-150 K, while both low-spin S = 1/2 and high-spin S = 3/2 states are populated at T > 150 K. These results explain the observation of two N-O vibrational modes at 1737 and 1649 cm(-1) in CD3CN for [Fe(NO)(N3PyS)]BF4 at room temperature. This {FeNO}(7) complex reacts with dioxygen upon photoirradiation with visible light in acetonitrile to generate a thiolate-ligated, nonheme iron(III)-nitro complex, [Fe(III)(NO2)(N3PyS)](+), which was characterized by EPR, FTIR, UV-vis, and CSI-MS. Isotope labeling studies, coupled with FTIR and CSI-MS, show that one O atom from O2 is incorporated in the Fe(III)-NO2 product. The O2 reactivity of [Fe(NO)(N3PyS)]BF4 in methanol is dramatically different from CH3CN, leading exclusively to sulfur-based oxidation, as opposed to NO· oxidation. A mechanism is proposed for the NO· oxidation reaction that involves formation of both Fe(III)-superoxo and Fe(III)-peroxynitrite intermediates and takes into account the experimental observations. The stability of the Fe(III)-nitrite complex is limited, and decay of [Fe(III)(NO2)(N3PyS)](+) leads to {FeNO}(7) species and sulfur oxygenated products. This work demonstrates that a single mononuclear, thiolate-ligated nonheme {FeNO}(7) complex can exhibit reactivity related to both nitric oxide dioxygenase (NOD) and nitrite reductase (NiR) activity. The presence of the thiolate donor is critical to both pathways, and mechanistic insights into these biologically relevant processes are presented.



FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

Dürr, Maximilian
Lehrstuhl für Bioanorganische Chemie
Ivanovic-Burmazovic, Ivana Prof. Dr.
Lehrstuhl für Bioanorganische Chemie


Zitierweisen

APA:
Mc Quilken, A.C., Matsumura, H., Dürr, M., Confer, A.M., Sheckelton, J.P., Siegler, M.A.,... Goldberg, D.P. (2016). Photoinitiated Reactivity of a Thiolate-Ligated, Spin-Crossover Nonheme {FeNO}(7) Complex with Dioxygen. Journal of the American Chemical Society, 138(9), 3107-17. https://dx.doi.org/10.1021/jacs.5b12741

MLA:
Mc Quilken, Alison C., et al. "Photoinitiated Reactivity of a Thiolate-Ligated, Spin-Crossover Nonheme {FeNO}(7) Complex with Dioxygen." Journal of the American Chemical Society 138.9 (2016): 3107-17.

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Zuletzt aktualisiert 2018-30-07 um 12:10