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Titolo:
Photoinduced reaction of arene singlets with carbon tetrachloride in zeolite Y
Autore:
Ellison, EH; Thomas, JK;
Indirizzi:
Univ Notre Dame, Dept Chem & Biochem, Notre Dame, IN 46556 USA Univ Notre Dame Notre Dame IN USA 46556 Biochem, Notre Dame, IN 46556 USA
Titolo Testata:
MICROPOROUS AND MESOPOROUS MATERIALS
fascicolo: 1-3, volume: 49, anno: 2001,
pagine: 15 - 24
SICI:
1387-1811(20011115)49:1-3<15:PROASW>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
POLYCYCLIC AROMATIC-HYDROCARBONS; PHOTOPHYSICAL PROBE MOLECULES; RESOLVED DIFFUSE REFLECTANCE; ATOM-INDUCED PHOSPHORESCENCE; ELECTRON-TRANSFER REACTIONS; CATION-PI-INTERACTION; INTRAZEOLITE PHOTOCHEMISTRY; FAUJASITE ZEOLITES; PYRENE; ANTHRACENE;
Keywords:
arene fluorescence; static quenching; NaY; carbon tetrachloride;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
51
Recensione:
Indirizzi per estratti:
Indirizzo: Thomas, JK Univ Notre Dame, Dept Chem & Biochem, 251 Niewland Sci Hall, Notre Dame, IN 46556 USA Univ Notre Dame 251 Niewland Sci Hall Notre Dame IN USA 46556 A
Citazione:
E.H. Ellison e J.K. Thomas, "Photoinduced reaction of arene singlets with carbon tetrachloride in zeolite Y", MICROP M M, 49(1-3), 2001, pp. 15-24

Abstract

Picosecond fluorescence methodologies combined with nanosecond, laser flash photolysis have been applied to examine the reaction of arene excited singlets with CCl4 in dehydrated, zeolite NaY. Fluorescence quenching by CCl4 was shown to originate mainly from a static process, with a much greater drop in fluorescence intensity than could be accounted for by a random distribution of CCl4 among the anthracene-occupied supercages. A similar effect was observed in a previous study of arene fluorescence quenching by nitroalkanes in NaY, and was explained by a mechanism involving coadsorption of thearene and nitroalkane to conjugate acid-base sites. This places the reactants in close proximity - a requirement for the static quenching. The results of the present study support this quenching mechanism by showing that a different electrophilic species (i.e., CCl4) also behaves like nitroalkanes,while reductive quenching by NN-dimethylaniline and triethylamine does not. Quenching of pyrene fluorescence by CCl4 produced pyrene radical cations through electron transfer to CCl4, with the cation yield proportional to the level of fluorescence quenching. One-third of these radical cations reacted with the fragmentation products of CCl4 anions to form stable products; the remaining fraction was stable, but reacted with added ferrocene. These results demonstrate that the addition of small quantities of CCl4 to the zeolite leads to efficient charge separation by a single-photon mechanism. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 07/07/20 alle ore 11:37:45