Toward New Horizons in Verdazyl-Nitroxide High-Spin Systems: Thermally Robust Tetraradical with Quintet Ground State

Toward New Horizons in Verdazyl-Nitroxide High-Spin Systems: Thermally Robust Tetraradical with Quintet Ground State Full article

Journal

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

Output data

Year: 2024, Volume: 146, Number: 19, Pages: 13666-13675 Pages count : 10 DOI: 10.1021/jacs.4c04391

Authors

Zayakin Igor A. ¹ , Petunin Pavel V. ² , Postnikov Pavel S. ² , Dmitriev Alexey A. ³ , Gritsan Nina P. ³ , Dorovatovskii Pavel ⁴ , Korlyukov Alexander ⁵ , Fedin Matvey V. ⁶ , Bogomyakov Artem S. ⁶ , Akyeva Anna Ya. ¹ , Novikov Roman A. ¹ , Shangin Pavel G. ¹ , Syroeshkin Mikhail A. ¹ , Burykina Julia V. ¹ , Tretyakov Evgeny V. ¹

Affiliations

1	N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Ave. 47, Moscow 119991, Russian Federation
2	Tomsk Polytechnic University, Tomsk 634050, Russian Federation
3	V.V. Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Sciences, Institutskaya Str. 3, Novosibirsk 630090, Russian Federation
4	NRC Kurchatov Institute, Moscow 123182, Russian Federation
5	A.N. Nesmeyanov Institute of Organoelement Compounds, 28 Vavilov Str., Moscow 119991, Russian Federation
6	International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya Str. 3a, Novosibirsk 630090, Russian Federation

High-spin organic tetraradicals with significant intramolecular exchange interactions have high potential for advanced technological applications and fundamental research, but examples reported to date exhibit limited stability and processability. In this work, we designed the first tetraradical based on an oxoverdazyl core and nitronyl nitroxide radicals and successfully synthesized it using a palladium-catalyzed cross-coupling reaction of an oxoverdazyl radical bearing three iodo-phenylene moieties with a gold(I) nitronyl nitroxide-2-ide complex in the presence of a recently developed efficient catalytic system. The molecular and crystal structures of the tetraradical were confirmed by single crystal X-ray diffraction analysis. The tetraradical possesses good thermal stability with decomposition onset at ∼125 °C in an inert atmosphere; in a toluene solution upon prolonged heating at 90 °C in air, no decomposition was observed. The resulting unique verdazyl-nitroxide conjugate was thoroughly studied using a range of experimental and theoretical techniques, such as SQUID magnetometry of polycrystalline powders, EPR spectroscopy in various matrices, cyclic voltammetry, and high-level quantum chemical calculations. All collected data confirm the high thermal stability of the resulting tetraradical and quintet multiplicity of its ground state, which makes the synthesis of this important paramagnet a new milestone in the field of creating high-spin systems.

Zayakin I.A. , Petunin P.V. , Postnikov P.S. , Dmitriev A.A. , Gritsan N.P. , Dorovatovskii P. , Korlyukov A. , Fedin M.V. , Bogomyakov A.S. , Akyeva A.Y. , Novikov R.A. , Shangin P.G. , Syroeshkin M.A. , Burykina J.V. , Tretyakov E.V.
Toward New Horizons in Verdazyl-Nitroxide High-Spin Systems: Thermally Robust Tetraradical with Quintet Ground State
Journal of the American Chemical Society. 2024. V.146. N19. P.13666-13675. DOI: 10.1021/jacs.4c04391 Scopus OpenAlex

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