Hole Transfer Equilibrium in Rigidly Linked Bichromophoric Molecules
Author(s) -
L. Chen,
N. D. Qi,
Abdelaziz Houmam,
Danial D. M. Wayner,
Stephen J. Weininger,
W. Grant McGimpsey
Publication year - 1999
Publication title -
the journal of physical chemistry a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.756
H-Index - 235
eISSN - 1520-5215
pISSN - 1089-5639
DOI - 10.1021/jp9922211
Subject(s) - anthracene , chemistry , chromophore , intramolecular force , photochemistry , ultrafast laser spectroscopy , electrochemistry , absorption (acoustics) , radical ion , absorption spectroscopy , photoionization , laser , ion , organic chemistry , materials science , electrode , ionization , physics , quantum mechanics , optics , composite material
Two bichromophoric molecules consisting of anthracene and diphenylpolyene moieties linked by two fused norbornyl bridges undergo photoionization upon ultraviolet (UV) pulsed laser irradiation. The simultaneous observation of the cation radicals of both anthracene and polyene groups points to a rapid (nanosecond or faster) intramolecular hole transfer equilibrium between the two chromophores. The existence of an equilibrium is supported by the results of one- and two-laser transient absorption and electrochemical experiments. Equilibrium constants (293 K) were determined by both transient absorption and cyclic voltammetry measurements and were independent of the method used within experimental error. For A-sp-VB, which contains anthracene and vinyldiphenylbutadiene chromophores, Keq = 4.0 ? 2 (transient absorption) and 3.2 ? 2 (electrochemical), favoring the anthracene cation radical. For A-sp-VS, containing anthracene and vinylstilbene groups, Keq = 70 ? 30 (transient absorption) and 105 ? 50 (electrochemical), favoring the anthracene cation radical.Peer reviewed: YesNRC publication: Ye
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