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Journal article

Kinetic studies on the reaction of NO with iron(ii) complexes using low temperature stopped-flow techniques

Authors list: Specht, P; Oßberger, M; Klüfers, P; Schindler, S

Publication year: 2020

Pages: 9480-9486

Journal: Dalton Transactions

Volume number: 49

Issue number: 27

ISSN: 1477-9226

DOI Link: https://doi.org/10.1039/d0dt01764g

Publisher: Royal Society of Chemistry

Abstract:

Low temperature stopped-flow techniques were used to investigate the reaction of three different iron(II) complexes with nitrogen monoxide. The kinetic studies allowed calculation of the activation parameters from the corresponding Eyring plots for all three systems. The reaction of iron(II) chloride with NO leading to the formation of MNIC (mononitrosyl-iron-complex) and DNIC (dinitrosyl-iron-complex) led to activation parameters of ΔH^‡ = 55.4 ± 0.4 kJ mol⁻¹ and ΔS^‡ = 13 ± 2 J K⁻¹ mol⁻¹ for MNIC and ΔH^‡ = 32 ± 6 kJ mol⁻¹ and ΔS^‡ = −193 ± 21 J K⁻¹ mol⁻¹ for DNIC. Formation of MNIC turned out to be much faster in comparison with DNIC. In contrast, activation parameters for the formation of monoculear [Fe(bztpen)(NO)](OTf)₂ (bztpen = N-benzyl-N,N′,N′-tris(2-pyridylmethyl)-ethylenediamine) ΔH^‡ = 17.8 ± 0.8 kJ mol⁻¹ and ΔS^‡ = −181 ± 3 J K⁻¹ mol⁻¹ supported an associative mechanism. Interestingly, [Fe(bztpen)(CH₃CN)](OTf)₂ does not react with dioxygen at all. Furthermore, activation parameters of ΔH^‡ = 37.7 ± 0.7 kJ mol⁻¹ and ΔS^‡ = −66 ± 3 J K⁻¹ mol⁻¹ were obtained for the reaction of NO with the dinuclear iron(II) H-HPTB complex (H-HPTB = N,N,N′,N′-tetrakis(2-benzimidazolylmethyl)-2-hydroxy-1,3-diaminopropane), [Fe₂(H-HPTB)(Cl)₃]. The kinetic data allowed postulation of the mechanisms for all of these reactions.

Authors/Editors

- Uni.-Prof. Dr. Siegfried Adolf Schindler

Citation Styles

Harvard Citation style: Specht, P., Oßberger, M., Klüfers, P. and Schindler, S. (2020) Kinetic studies on the reaction of NO with iron(ii) complexes using low temperature stopped-flow techniques, Dalton Transactions, 49(27), pp. 9480-9486. https://doi.org/10.1039/d0dt01764g

APA Citation style: Specht, P., Oßberger, M., Klüfers, P., & Schindler, S. (2020). Kinetic studies on the reaction of NO with iron(ii) complexes using low temperature stopped-flow techniques. Dalton Transactions. 49(27), 9480-9486. https://doi.org/10.1039/d0dt01764g