Series of Fluorinated Benzimidazole-Substituted Nitronyl Nitroxides: Synthesis, Structure, Acidity, Redox Properties, and Magnetostructural Correlations

Series of Fluorinated Benzimidazole-Substituted Nitronyl Nitroxides: Synthesis, Structure, Acidity, Redox Properties, and Magnetostructural Correlations Full article

Journal

Journal of Organic Chemistry
ISSN: 1520-6904 , E-ISSN: 0022-3263

Output data

Year: 2023, Volume: 88, Number: 15, Pages: 10355-10370 Pages count : 16 DOI: 10.1021/acs.joc.2c01793

Authors

Tretyakov Evgeny ¹ , Fedyushin Pavel ¹ , Bakuleva Nadejda ¹ , Korlyukov Alexander ² , Dorovatovskii Pavel ³ , Gritsan Nina ⁴ , Dmitriev Alexey ⁴ , Akyeva Anna ¹ , Syroeshkin Mikhail ¹ , Stass Dmitri ⁴ , Zykin Mikhail ⁵ , Efimov Nikolay ⁵ , Luneau Dominique ⁶

Affiliations

1	N. D. Zelinsky Institute of Organic Chemistry, Leninsky Prospect 47, Moscow119991, Russia
2	A. N. Nesmeyanov Institute of Organoelement Compounds, 28 Vavilov Street, Moscow119991, Russia
3	NRC Kurchatov Institute, Akademika Kurchatova Pl. 1, Moscow123182, Russia
4	V. V. Voevodsky Institute of Chemical Kinetics and Combustion, 3 Institutskaya Str., Novosibirsk630090, Russia
5	N. S. Kurnakov Institute of General and Inorganic Chemistry, Leninsky Prospect 31, Moscow119991, Russia
6	Laboratoire des Multimatériaux et Interfaces (UMR 5615), Université Claude Bernard Lyon-1, Campus de La Doua, Villeurbanne Cedex69622, France

A special series of nitronyl nitroxides was synthesized: 2-(benzimidazol-2′-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyls mono-, di-, tri-, or tetrafluorinated on the benzene ring. The structure of all paramagnets was unambiguously confirmed by single-crystal X-ray diffraction. It was found that in crystals, the radicals are assembled into chains due to intermolecular H-bonds between the benzimidazole moiety (H-bond donor) and the nitronyl nitroxide group or benzimidazole ring (H-bond acceptor). The magnetic properties of nitronyl nitroxides depend on the type of binding of radicals by H-bonds. The magnetic motif of 4-fluoro-, 5-fluoro-, 4,6-difluoro-, 4,5,6-trifluoro-, 4,5,7-trifluoro-, and 4,5,6,7-tetrafluoro-derivatives, as well as the nonfluorinated compound, consists of ferromagnetic chains (J/kB ≈ 20–40 K) formed by the McConnell type I mechanism. In the 5,6-difluoro- and 4,5-difluoro-derivatives, the distances between the paramagnetic centers are large, as a result of which the exchange interactions are weak. According to cyclic voltammetry, paramagnets are oxidized reversibly, while their reduction is a quasi-reversible electron transfer (EC mechanism); experimental redox potentials of radicals correlate well with the calculated values. Quantum chemical assessment of the acidity of benzimidazolyl-substituted nitronyl nitroxides revealed that the introduction of fluorine atoms into the benzene ring enhances the acidity of the paramagnets by more than 5 orders of magnitude.

Tretyakov E. , Fedyushin P. , Bakuleva N. , Korlyukov A. , Dorovatovskii P. , Gritsan N. , Dmitriev A. , Akyeva A. , Syroeshkin M. , Stass D. , Zykin M. , Efimov N. , Luneau D.
Series of Fluorinated Benzimidazole-Substituted Nitronyl Nitroxides: Synthesis, Structure, Acidity, Redox Properties, and Magnetostructural Correlations
Journal of Organic Chemistry. 2023. V.88. N15. P.10355-10370. DOI: 10.1021/acs.joc.2c01793 WOS Scopus OpenAlex

Web of science:	WOS:000874243600001
Scopus:	2-s2.0-85139964350
OpenAlex:	W4302017541

DB	Citing
OpenAlex	10
Scopus	6
Web of science	6