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Reversible dissociation of singly-bonded (C60(-))2 dimers in (MV•+)2(C60(--))2.Solvent salt containing paramagnetic methyl viologen MV(•+) radical cationsстатья
- Авторы: Konarev Dmitri V., Khasanov Salavat S., Obraztsov Oleg A., Otsuka Akihiro, Yamochi Hideki, Kitagawa Hiroshi, Lyubovskaya Rimma N.
- Журнал: New Journal of Chemistry
- Том: 45
- Номер: 3
- Год издания: 2021
- Издательство: Royal Society of Chemistry
- Местоположение издательства: United Kingdom
- Первая страница: 1163
- Последняя страница: 1167
- DOI: 10.1039/d0nj05076h
- Аннотация: Methyl viologen (MV(2+))(Cl-)2 is reduced by cesium anthracene to form neutral MV(0) whose interaction with C60 produces(MV.+)2(C60(-))2. 2.5C6H4Cl2. 0.5C6H6 (1). X-ray diffraction analysis shows that C60(.-) radical anions form singly-bonded (C60(-))2 dimers at 100 K and are arranged in zig-zag layers. According to EPR, the dimers dissociate in the 235–375 K range. Salt 1 contains two paramagnetic MV(.+) and C60(.-) species in the monomeric phase with strong exchange interaction. This interaction is switched off at the dimerization of C60(.-) and magnetically isolated MV(.+) pairs are formed. Spins of MV(.+) are strongly antiferromagnetically coupled in the pairs with the Weiss temperature of 32 K and J/kB = -20 K. MV(.+) shows narrow EPR signal with g = 2.0039 and the linewidth of about 0.2 mT (T = 100 K). A plot of natural logarithm of the dimerization constant vs. reverse temperature (at 235–375 K) allows the estimation of the energy of single C–C bonds in the (C60(-))2 dimers as 38.2 +- 0.8 kJ mol.
- Добавил в систему: Конарев Дмитрий Валентинович