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001-es BibID:	BIBFORM112580
035-os BibID:	(WoS)000367561100005 (Scopus)84952946597
Első szerző:	Gabričević, Mario
Cím:	Hydrogen Isotope Exchange of Chlorinated Ethylenes in Aqueous Solution: Possibly a Termolecular Liquid Phase Reaction / Mario Gabričević, Gábor Lente, István Fábián
Dátum:	2015
ISSN:	1089-5639
Megjegyzések:	This work reports an experimental study of the hydrogen/deuterium exchange in the basic aqueous solutions of trichloroethylene, trans-1,2-dichloroethylene, and cis-1,2-dichloroethylene using 1H NMR as a monitoring method. 1,1-Dichlorethylene was also investigated but found not to exchange hydrogen isotopes with water. The kinetics of isotope exchange features two different pathways, the first is first order with respect to hydroxide ion, whereas the second is second order. The first pathway is interpreted as a straightforward bimolecular reaction between chloroethylene and hydroxide ion, which leads to the deprotonation of chloroethylene. The second pathway involves a transition state with the association of one molecule of the chloroethylene and two hydroxide ions. It is shown that the second pathway could involve the formation of a precursor complex composed of one chloroethylene molecule and one hydroxide ion, but a direct termolecular elementary reaction is also feasible, which is shown by deriving a theoretical highest limit for the rate constants of termolecular reactions in solution.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk 1H NMR chlorinated ethylenes isotope exchange
Megjelenés:	Journal Of Physical Chemistry A. - 119 : 51 (2015), p. 12627-12634. -
További szerzők:	Lente Gábor (1973-) (vegyész) Fábián István (1956-) (vegyész)
Pályázati támogatás:	4.2.2.A-11/1/KONV-2012-0043 TÁMOP 77936 OTKA OTKA-105156 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM103957
035-os BibID:	(cikkazonosító)e4045 (WOS)000505510900001 (Scopus)85077852751
Első szerző:	Gabričević, Mario
Cím:	Kinetic detection of osmium(VI) ester intermediates during the OsO4-mediated aqueous dihydroxylation of chloroethylenes / Mario Gabričević, Gábor Lente, István Fábián
Dátum:	2020
ISSN:	0894-3230 1099-1395
Megjegyzések:	The kinetics and mechanism of the cis dihydroxylation of cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, and trichloroethylene by osmium tetroxide was studied systematically in aqueous solution. The stoichiometry of the process was determined based on the principle of continuous variation of reactant ratios with spectrophotometric detection. The results always showed 1:1 stoichiometry, which is in agreement with dihydroxylation. All three reactions were found to proceed in two distinct steps. The first step occurred on a time scale of seconds and was associated with a minor change in absorbance and was identified as the formation of a 1:1 adduct between the two reagents, which is the osmium(VI) ester that plays a decisive role in catalytic applications. This species is formed in an equilibrium that is very much shifted toward the reactants, so the osmium(VI) complex is a short-lived intermediate of the process, which is detected kinetically, but its concentration is never high enough for structural characterization. The second reaction is accompanied by major spectral changes; it involves the formation of the final products. Our results clearly show that it is possible to detect the intermediate of the process by careful kinetic studies. It is also possible that the same strategy might be successful in other OsO4-dependent dihydroxylation processes.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk aqueous chemistry osmium (VI) ester oxidation of alkenes relaxation kinetics stopped-flow
Megjelenés:	Journal of Physical Organic Chemistry. - 33 : 4 (2020), p. 1-10. -
További szerzők:	Lente Gábor (1973-) (vegyész) Fábián István (1956-) (vegyész)
Pályázati támogatás:	GINOP-2.3.2-15-2016-00008 GINOP K-17-124983 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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