|
ИСТИНА |
Войти в систему Регистрация |
ИСТИНА ЦЭМИ РАН |
||
Novel Oxidovanadium Complexes with Redox-Active R-Mian and R-Bian Ligands: Synthesis, Structure, Redox and Catalytic Properties https://doi.org/10.3390/molecules26185706статья
Дата последнего поиска статьи во внешних источниках: 23 сентября 2021 г.
- Авторы: Lukoyanov Anton N., Fomenko Iakov S., Gongola Marko I., Shul’pina Lidia S., Ikonnikov Nikolay S., Shul’pin Georgiy B., Ketkov Sergey Y., Fukin Georgy K., Rumyantcev Roman V., Novikov Alexander S., Nadolinny Vladimir A., Sokolov Maxim N., Gushchin Artem L.
- Журнал: Molecules
- Том: 26
- Номер: 18
- Год издания: 2021
- Издательство: MDPI
- Местоположение издательства: Basel, Switzerland
- Номер статьи: 5706
- DOI: 10.3390/molecules26185706
- Аннотация: A new monoiminoacenaphthenone 3,5-(CF3)2C6H3-mian (complex 2) was synthesized and further exploited, along with the already known monoiminoacenaphthenone dpp-mian, to obtain oxidovanadium(IV) complexes [VOCl2(dpp-mian)(CH3CN)] (3) and [VOCl(3,5-(CF3)2C6H3-bian)(H2O)][VOCl3(3,5-(CF3)2C6H3-bian)]·2.85DME (4) from [VOCl2(CH3CN)2(H2O)] (1) or [VCl3(THF)3]. The structure of all compounds was determined using X-ray structural analysis. The vanadium atom in these structures has an octahedral coordination environment. Complex 4 has an unexpected structure. Firstly, it contains 3,5-(CF3)2C6H3-bian instead of 3,5-(CF3)2C6H3-mian. Secondly, it has a binuclear structure, in contrast to 3, in which two oxovanadium parts are linked to each other through V=O···V interaction. This interaction is non-covalent in origin, according to DFT calculations. In structures 2 and 3, non-covalent π-π staking interactions between acenaphthene moieties of the neighboring molecules (distances are 3.36–3.40 Å) with an estimated energy of 3 kcal/mol were also found. The redox properties of the obtained compounds were studied using cyclic voltammetry in solution. In all cases, the reduction processes initiated by the redox-active nature of the mian or bian ligand were identified. The paramagnetic nature of complexes 3 and 4 has been proven by EPR spectroscopy. Complexes 3 and 4 exhibited high catalytic activity in the oxidation of alkanes and alcohols with peroxides. The yields of products of cyclohexane oxidation were 43% (complex 3) and 27% (complex 4). Based on the data regarding the study of regio- and bond-selectivity, it was concluded that hydroxyl radicals play the most crucial role in the reaction. The initial products in the reactions with alkanes are alkyl hydroperoxides, which are easily reduced to their corresponding alcohols by the action of triphenylphosphine (PPh3). According to the DFT calculations, the difference in the catalytic activity of 3 and 4 is most likely associated with a different mechanism for the generation of ●OH radicals. For complex 4 with electron-withdrawing CF3 substituents at the diimine ligand, an alternative mechanism, different from Fenton’s and involving a redox-active ligand, is assumed.
- Добавил в систему: Шульпин Георгий Борисович
Прикрепленные файлы
| № | Имя | Описание | Имя файла | Размер | Добавлен |
|---|---|---|---|---|---|
| 1. | Полный текст | Molecules-Gushin-2021-vanadium.pdf | 1,8 МБ | 22 октября 2021 [ShulpinaLS.] | |
| 2. | экспертное заключение | ekspertnoe_zaklyuchenie-2021-Molecules.jpeg | 459,7 КБ | 27 сентября 2021 [ShulpinaLS.] |