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Titolo:
CHAIN-LENGTH-DEPENDENT AND SOLVENT-DEPENDENT INTRAMOLECULAR PROTON-TRANSFER IN STYRENE AMINE EXCIPLEXES
Autore:
LEWIS FD; REDDY GD; BASSANI DM; SCHNEIDER S; GAHR M;
Indirizzi:
NORTHWESTERN UNIV,DEPT CHEM,2145 SHERIDAN RD EVANSTON IL 60208 UNIV ERLANGEN NURNBERG,INST PHYS & THEORET CHEM D-91058 ERLANGEN GERMANY
Titolo Testata:
Journal of the American Chemical Society
fascicolo: 2, volume: 116, anno: 1994,
pagine: 597 - 605
SICI:
0002-7863(1994)116:2<597:CASIP>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
PICOSECOND LASER PHOTOLYSIS; PHOTOINDUCED ELECTRON-TRANSFER; CHARGE-TRANSFER; PHOTOCHEMICAL ADDITION; ACETONITRILE SOLUTION; EXCITED BENZOPHENONE; HETEROEXCIMER SYSTEMS; REDUCTION PROCESS; TERTIARY-AMINES; PHENYL KETONES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
78
Recensione:
Indirizzi per estratti:
Citazione:
F.D. Lewis et al., "CHAIN-LENGTH-DEPENDENT AND SOLVENT-DEPENDENT INTRAMOLECULAR PROTON-TRANSFER IN STYRENE AMINE EXCIPLEXES", Journal of the American Chemical Society, 116(2), 1994, pp. 597-605

Abstract

The photochemical and photophysical behavior of several ((N,N-dimethylamino)alkyl)styrenes in which the amino group is attached to the styrene alpha- or beta-carbon by a methyl, ethyl, propyl, or butyl polymethylene chain has been investigated. Efficient intramolecular addition of an aminomethyl C-H to styrene is observed in nonpolar solvents for the (aminoethyl)styrenes, and addition of anaminomethylene C-H is observed for the (aminobutyl) styrenes. However, the (aminomethyl)- and (aminopropyl)styrenes do not undergo intramolecular addition reactions. Both the reactive and unreactive (aminoalkyl)styrenes form fluorescentsinglet exciplexes in nonpolar and polar solvents. The results of exciplex and product quenching by an added primary amine indicate that the fluorescent exciplex is an intermediate in the addition reactions ofthe (aminoalkyl)styrenes. Activation parameters for both exciplex formation and exciplex proton transfer have been determined. Highly regioselective intramolecular proton transfer is proposed to occur via least motion pathways from the lowest energy folded conformations of the singlet exciplex intermediates in nonpolar solvents. The solvent dependence of exciplex proton transfer, fluorescence, intersystem crossing, and nonradiative decay is attributed to a change in exciplex conformation from folded in nonpolar solvents to extended in solvents more polar than diethyl ether.

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Documento generato il 26/11/20 alle ore 20:32:33