CIDEP of fullerene C-60 biradical bisadducts by intramolecular triplet-triplet quenching: a novel spin polarization mechanism for biradicals

Citation
C. Corvaja et al., CIDEP of fullerene C-60 biradical bisadducts by intramolecular triplet-triplet quenching: a novel spin polarization mechanism for biradicals, CHEM P LETT, 330(3-4), 2000, pp. 287-292
Citations number
29
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
CHEMICAL PHYSICS LETTERS
ISSN journal
00092614 → ACNP
Volume
330
Issue
3-4
Year of publication
2000
Pages
287 - 292
Database
ISI
SICI code
0009-2614(20001110)330:3-4<287:COFCBB>2.0.ZU;2-6
Abstract
[60]fullerene bisadducts containing the C-2 nu-symmetrical 2,2,5,5-tetramet hylpyrroiidine-1-oxyl moiety have been synthesized. Their EPR spectrum is t ypical of nitroxide biradicals with electron exchange interaction J of the same order of the nitrogen hyperfine coupling. From the EPR spectrum the ab solute value of J was obtained, while the sign was measured by ENDOR. When the derivatives are photoexcited strong spin polarization is observed with A/E/A/E or E/A/E/A patterns, according to a positive or a negative sign of J. This behavior is accounted for by an intramolecular triplet-triplet inte raction. The analogy with the polarization of transient spin correlated rad ical pairs is pointed out. (C) 2000 Elsevier Science B.V. All rights reserv ed.