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Titolo:
Long-lived photoproduced radical ions in tetrathiafulvalenes covalently tethered to C-60
Autore:
Simonsen, KB; Konovalov, VV; Konovalova, TA; Kawai, T; Cava, MP; Kispert, LD; Metzger, RM; Becher, J;
Indirizzi:
Univ Alabama, Dept Chem, Tuscaloosa, AL 35487 USA Univ Alabama TuscaloosaAL USA 35487 Dept Chem, Tuscaloosa, AL 35487 USA Odense Univ, Dept Chem, DK-5230 Odense M, Denmark Odense Univ Odense Denmark M Univ, Dept Chem, DK-5230 Odense M, Denmark
Titolo Testata:
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2
fascicolo: 3, , anno: 1999,
pagine: 657 - 665
SICI:
0300-9580(199903):3<657:LPRIIT>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOTOINDUCED ELECTRON-TRANSFER; BUCKMINSTERFULLERENE C-60; INTRAMOLECULAR ELECTRON; CYCLIC VOLTAMMETRY; CONDUCTING POLYMER; CHARGE SEPARATION; SPIN-RESONANCE; DONOR; FULLERENES; PHOTOSYNTHESIS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
54
Recensione:
Indirizzi per estratti:
Indirizzo: Metzger, RM Univ Alabama, Dept Chem, Tuscaloosa, AL 35487 USA Univ Alabama Tuscaloosa AL USA 35487 Tuscaloosa, AL 35487 USA
Citazione:
K.B. Simonsen et al., "Long-lived photoproduced radical ions in tetrathiafulvalenes covalently tethered to C-60", J CHEM S P2, (3), 1999, pp. 657-665

Abstract

C-60 or [60]fullerene, a reversible one- to six-electron acceptor with moderate first electron. affinity, was covalently linked, via a 1,3-dipolar addition reaction using azomethine ylides and two flexible insulating sigma-chains of different lengths, to a tetrathioalkyltetrathiafulvalene, a reversible one- to two-electron donor with low first ionization potential, yielding molecules 1 and 2. The electrochemical oxidation and reduction waves arethe same as those of the separate components; UV-VIS spectra indicate no appreciable charge transfer in the ground state between the donor and acceptor moieties of these D-sigma-A systems 1 and 2: there is only a weak shoulder at 800 nm (epsilon approximate to 200 L mol(-1) cm(-1)), which could be the intervalence transfer band. These same molecules, as well as their donor and acceptor components takenseparately, were electrochemically oxidized/reduced in liquid solutions, and also irradiated with laser light in low-temperature glasses. The electron paramagnetic resonance (EPR) spectra revealed photoexcited electron transfer at 77 K, with resulting S = 1/2 radical cation and radical anion states. In a glass at 77 K these radical signals survive a long time (up to several days) after the end of light irradiation. This may be separately solvated pairs of long-lived radicals D.+-sigma-A and D-sigma-A(.-) or, less likely, a long-lived excited-state zwitterionic biradical D.+-sigma-A(.-) with increasing temperature and the onset of diffusional motion, the EPR signals disappear.

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Documento generato il 18/09/20 alle ore 10:52:22