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Photochemistry of Charge‐Transfer Complexes in a Viologen Periodic Mesoporous Organosilica: Time Evolution from Femtoseconds to Minutes
Author(s) -
Álvaro Mercedes,
Ferrer Belén,
García Hermenegildo,
Hashimoto Shuichi,
Hiratsuka Masahiro,
Asahi Tsuyoshi,
Masuhara Hiroshi
Publication year - 2004
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200301038
Subject(s) - viologen , photoexcitation , photochemistry , nanosecond , femtosecond , halide , chemistry , mesoporous organosilica , mesoporous material , ion , electron transfer , radical ion , charge (physics) , chemical physics , materials science , inorganic chemistry , mesoporous silica , atomic physics , catalysis , organic chemistry , laser , optics , excited state , physics , quantum mechanics
Persistent radical cations can be generated in V∝PMO, a periodic mesoporous organosilica incorporating a viologen in its silicate framework. Photoexcitation of V∝PMO forms a geminate viologen–halide ion pair that can undergo rapid charge recombination or electron hopping to form the nongeminate ion pair, which persists for minutes (see picture). In contrast, viologen–halide CT complexes in solution undergo complete charge recombination on the sub‐nanosecond timescale.