Platform for High-Spin Molecules: A Verdazyl-Nitronyl Nitroxide Triradical with Quartet Ground State

Platform for High-Spin Molecules: A Verdazyl-Nitronyl Nitroxide Triradical with Quartet Ground State Full article

Journal

Journal of the American Chemical Society
ISSN: 0002-7863 , E-ISSN: 1520-5126

Output data

Year: 2021, Volume: 143, Number: 21, Pages: 8164-8176 Pages count : 13 DOI: 10.1021/jacs.1c02938

Authors

Tretyakov Evgeny V ¹ , Petunin Pavel V ² , Zhivetyeva Svetlana I ³ , Gorbunov Dmitry E ⁴ , Gritsan Nina P ⁴ , Fedin Matvey V ⁵ , Stass Dmitri V ^6,4 , Samoilova Rimma I ⁴ , Bagryanskaya Irina Yu ³ , Shundrina Inna K ³ , Bogomyakov Artem S ⁵ , Kazantsev Maxim S ³ , Postnikov Pavel S ² , Trusova Marina E ² , Ovcharenko Victor I ⁵

Affiliations

1	N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Ave. 47, Moscow 119991, Russian Federation
2	Tomsk Polytechnic University, Lenin Ave. 30, Tomsk 634050, Russian Federation
3	N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, Ac. Lavrentiev Ave. 9, Novosibirsk 630090, Russian Federation
4	V.V. Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Sciences, Institutskaya Str. 3, Novosibirsk 630090, Russian Federation
5	International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya Str. 3a, Novosibirsk 630090, Russian Federation
6	Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russian Federation

Thermally resistant air-stable organic triradicals with a quartet ground state and a large energy gap between spin states are still unique compounds. In this work, we succeeded to design and prepare the first highly stable triradical, consisting of oxoverdazyl and nitronyl nitroxide radical fragments, with a quartet ground state. The triradical and its diradical precursor were synthesized via a palladium-catalyzed cross-coupling reaction of diiodoverdazyl with nitronyl nitroxide-2-ide gold(I) complex. Both paramagnetic compounds were fully characterized by single-crystal X-ray diffraction analysis, superconducting quantum interference device magnetometry, EPR spectroscopy in various matrices, and cyclic voltammetry. In the diradical, the verdazyl and nitronyl nitroxide centers demonstrated full reversibility of redox process, while for the triradical, the electrochemical reduction and oxidation proceed at practically the same redox potentials, but become quasi-reversible. A series of high-level CASSCF/NEVPT2 calculations was performed to predict inter- and intramolecular exchange interactions in crystals of di- and triradicals and to establish their magnetic motifs. Based on the predicted magnetic motifs, the temperature dependences of the magnetic susceptibility were analyzed, and the singlet–triplet (135 ± 10 cm–1) and doublet-quartet (17 ± 2 and 152 ± 19 cm–1) splitting was found to be moderate. Unique high stability of synthesized verdazyl-nitronylnitroxide triradical opens new perspectives for further functionalization and design of high-spin systems with four or more spins.

Tretyakov E.V. , Petunin P.V. , Zhivetyeva S.I. , Gorbunov D.E. , Gritsan N.P. , Fedin M.V. , Stass D.V. , Samoilova R.I. , Bagryanskaya I.Y. , Shundrina I.K. , Bogomyakov A.S. , Kazantsev M.S. , Postnikov P.S. , Trusova M.E. , Ovcharenko V.I.
Platform for High-Spin Molecules: A Verdazyl-Nitronyl Nitroxide Triradical with Quartet Ground State
Journal of the American Chemical Society. 2021. V.143. N21. P.8164-8176. DOI: 10.1021/jacs.1c02938 WOS Scopus OpenAlex

Web of science:	WOS:000659443000032
Scopus:	2-s2.0-85107710941
OpenAlex:	W3162343036

DB	Citing
OpenAlex	63
Scopus	52
Web of science	57