The Journal European Journal of Organic Chemistry (IF 3.029) published the article with the participation of the NIOCh's researchers Svetlana I. Zhivetyeva, Irina Yu. Bagryanskaya, Maxim S. Kazantsev and Evgeny V. Tretyakov:
Preparation of Multi‐Spin Systems: A Case Study of Tolane‐Bridged Verdazyl‐Based Hetero‐Diradicals
Darya E. Votkina, Pavel V. Petunin, Svetlana I. Zhivetyeva, Irina Yu. Bagryanskaya, Mikhail N. Uvarov, Maxim S. Kazantsev, Marina E. Trusova, Evgeny V. Tretyakov, Pavel S. Postnikov
European Journal of Organic Chemistry,
Volume 2020, Issue13, April 7, 2020 Pages 1996-2004
First published:04 March 2020
DOI:https://doi.org/10.1002/ejoc.202000044
Hot Topic: C-C Coupling
Abstract
Sonogashira coupling was investigated as a promising strategy for the synthesis of a multi‐spin system based on ‘Kuhn'‐verdazyls, oxoverdazyls, and nitronyl‐nitroxides. Eleven hetero‐diradicals were isolated in up to 56 % yields by a one‐step protocol. Oxoverdazyl radicals had the highest reactivity. This research opens access to simple design and investigation of conjugated diradicals.
Abstract
Iodine‐ and ethynyl‐containing 'Kuhn'‐verdazyls, oxoverdazyls, and nitronyl nitroxides were investigated as building blocks for the preparation of multi‐spin systems via the Sonogashira reaction, and, as a result, eleven diradicals were prepared with fair yields. The reactivity of the building blocks indicates that oxoverdazyl iodides are effective starting components for the synthesis of diradicals via the Sonogashira coupling. The described one‐step protocol allows combining different spin units, thereby facilitating the design of tolane‐bridged diradicals and screening of their properties. The novel compounds were characterized by cyclic voltammetry, UV/Vis and electron spin resonance (ESR) spectroscopy. Although the electrochemical investigation and electronic spectra showed a negligible influence of radical moieties on each other, ESR data revealed a strong exchange interaction between two unpaired electrons. The prepared verdazyl‐nitronylnitroxide diradicals have high stability at storage and hold promise for further investigation and application.
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