Реферат: For the first time, a quantitative approach is successfully used in the ESR study of new catalysts for olefin metathesis prepared by dissolution of WCl6 and MoCl5 in ionic liquids (hmimBF4, hpyrBF4, etc.). ESR monitoring of frozen probes taken upon interaction between the phases of an ionic liquid and hex-1-ene permits one to elucidate the key role of isolated paramagnetic complexes of W5+ and Mo5+ ions in catalysis. The use of MoCl5 as a starting reagent opens a way for a quantitative observation of paramagnetic active species in two liquid phases. It is shown that the reaction in the biphasic system proceeds as a heterogeneous catalytic process: virtually all the isolated W5+ or Mo5+ species are located in the ionic liquid. The kinetics of formation/accumulation of the isolated paramagnetic W5+ species at the initial slow step of W6+ reduction by an olefin agrees closely with the kinetics of metathesis leading to the formation of a C8 product. No induction period is observed in the case of Mo5+ ions. The number of the ESR-visible isolated paramagnetic Mo5+ complexes reaches ∼90% of the total number of molybdenum ions in the sample. Thus, the Mo(V) state of the active sites localized in ionic liquids is responsible for the further catalytic process. The same seems to be true for the W(V) species accumulated in the ionic liquid at the end of the first step of the reaction.

Библиографическая ссылка: Kucherov A.V. , Vasnev A.V. , Greish A.A. , Kustov L.M.
Catalytically active species in new metathesis systems [Wn+(Mon+)–ionic liquid–olefin]: A quantitative ESR study
Journal of Molecular Catalysis A: Chemical. 2005. V.237. N1-2. P.165-171. DOI: 10.1016/j.molcata.2005.04.045 WOS Scopus OpenAlex

Идентификаторы БД:

Web of science:	WOS:000230713100023
Scopus:	2-s2.0-21644473139
OpenAlex:	W2049879288

Цитирование в БД:

БД	Цитирований
OpenAlex	7
Scopus	10

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