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Solvent control in the protonation of [Cp*Mo(dppe)H-3] by CF3COOHстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 марта 2017 г.
- Авторы: Dub Pavel A., Baya Miguel, Houghton Jennifer, Belkova Natalia V., Daran Jean-Claude, Poli Rinaldo, Epstein Lina M., Shubina Elena S.
- Журнал: European Journal of Inorganic Chemistry
- Номер: 18
- Год издания: 2007
- Издательство: John Wiley & Sons Ltd.
- Местоположение издательства: United Kingdom
- Первая страница: 2813
- Последняя страница: 2826
- DOI: 10.1002/ejic.200700021
- Аннотация: The outcome of the reaction between [Cp*Mo(dppe)H-3][dppe = 1,2-bis(diphenylphosphanyl)ethane] and trifluoroacetic acid (TFA) is highly dependent on the solvent and the TFA/Mo ratio. The dihydride compound [Cp*Mo(dppe)H-2(O2CCF3)] is obtained selectively when the reaction is carried out in aromatic hydrocarbons (benzene, toluene) when using less than one equivalent of TFA. The dihydride is also the end product when THF or MeCN are used as solvent, independent of the TFA/Mo ratio. In benzene/toluene the use of excess acid has a profound effect, resulting in the formation of the tetrahydrido complex [Cp*Mo(dppe)H-4](+), which did not further evolve into the dihydrido product. Monitoring of the reaction by NMR and IR spectroscopy under different conditions (solvent, temperature, TFA/Mo ratio) reveals the rapid establishment of an equilibrium between the dihydrogen-bonded adduct, [Cp*Mo(dppe)H-3]center dot center dot center dot HO2CCF3, the ion-paired proton-transfer product, [Cp*Mo(dppe)H-4](+)center dot center dot center dot-O2CCF3, and the separated ions, followed by a slower irreversible transformation to the final dihydride product with H-2 evolution. The activation parameters of the H-2 evolution and M-OR product formation were determined. Excess TFA in low-polarity solvents stabilizes the separated charged species by forming the homoconjugate anion [CF3COO(CF3COOH)(n)](-). The effect of the solvent on the course of the reaction can be interpreted in terms of the different polarity, H-bonding ability, and coordinating power of the various solvent molecules. (c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007.
- Добавил в систему: Шубина Елена Соломоновна