Premium
Polar‐Solvent Effect on the Photocycloisomerization of Symmetrical Bis[anthracenes]: A Transient Ultrafast Kinetic Study
Author(s) -
Dvornikov Alexander S.,
Desvergne JeanPierre,
Oulianov Dmitri A.,
BouasLaurent Henri,
Rentzepis Peter M.
Publication year - 2001
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(20010919)84:9<2520::aid-hlca2520>3.0.co;2-4
Subject(s) - chemistry , methylcyclohexane , quantum yield , ultrafast laser spectroscopy , photochemistry , solvent , intramolecular force , polar , excimer , fluorescence , spectroscopy , yield (engineering) , solvent effects , zwitterion , picosecond , organic chemistry , toluene , laser , physics , quantum mechanics , astronomy , optics , materials science , molecule , metallurgy
Bis[anthracenes] are the few among the fluorescing nonconjugated bichromophores that possess photoreactive properties. The 9,9′‐[methylenebis(oxy)]bis[anthracenes] 1 (AOCH 2 OA) exhibit the highest known intramolecular photocycloaddition quantum yield from the S 1 state and, moreover, display a higher yield in polar solvents, an unexpected result for symmetrical systems. No excimer fluorescence was detected in solution at room temperature. The 10,10′‐dimethoxy derivative 1b was studied by picosecond (ps) laser spectroscopy. In nonpolar solvents (methylcyclohexane), S n ←S 1 was the only transient absorption detected, whereas, in polar solvents (MeCN), the growth and the decay of a second transient were recorded, and the second transient was attributed to a zwitterion A +. −A −. . The kinetics data were derived, and it was concluded that electron transfer and ion recombination should be at the origin of the observed rate enhancement of cycloadduct formation in polar solvents.