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Two pathways of proton transfer reaction to (triphos)Cu(eta(1)-BH4) via a dihydrogen bond [triphos=1,1,1-tris(diphenylphosphinomethyl)ethane]статья
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: 11 марта 2017 г.
- Авторы: Golub I.E., Filippov O.A., Belkova N.V., Epstein L.M., Rossin A., Peruzzini M., Shubina E.S.
- Журнал: Dalton Transactions
- Том: 45
- Номер: 22
- Год издания: 2016
- Издательство: Royal Society of Chemistry
- Местоположение издательства: United Kingdom
- Первая страница: 9127
- Последняя страница: 9135
- DOI: 10.1039/c6dt01104g
- Аннотация: The interaction of the. 1-tetrahydroborate copper(I) complex (triphos)Cu(eta(1)-BH4) (1) with proton donors [CF3CH2OH (TFE), (CF3)(2)CHOH (HFIP), (CF3)(3)COH (PFTB), PhOH, p-NO2C6H4OH (PNP), p-NO(2)C(6)H(4)NvNC(6)H(4)OH (PNAP), CF3OH] was a subject of a combined IR spectroscopic and theoretical investigation. Spectral (Delta nu.) and thermodynamic (Delta H) parameters of dihydrogen bond (DHB) formation were determined experimentally. The terminal hydride ligand (characterized by the basicity factor E-j(BH) = 0.87 +/- 0.01) is found to be a site of proton transfer which begins with nucleophilic substitution of BH4- by the alcohol oxygen atom on the copper center (BH pathway). The activation barrier computed for (CF3)(2)CHOH in CH2Cl2 - Delta G(273)(double dagger)K = 20.6 kcal mol(-1) - is in good agreement with the experimental value (Delta G(270)(double dagger)K = 20.0 kcal mol(-1)). An abnormal dependence of the reaction rate on the proton donor strength found experimentally in dichloromethane is explained computationally on the basis of the variation of the structural and energetic details of this process with the proton donor strength. In the second reaction mechanism found (CuH pathway), DHB complexes with the initial ROH coordination to the bridging hydride lead to B-Hbr bond cleavage with BH3 elimination. "Copper assistance" via the Cu center dot center dot center dot O interaction is not involved. This mechanism can be evoked to explain the occurrence of proton transfer in coordinating solvents.
- Добавил в систему: Голуб Игорь Евгеньевич