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Rapid Communication Effect of Alkali Metal Ions on Photochromic Behavior of Bisviologen‐incorporated Oligo‐oxyethylene Units ¶
Author(s) -
Kuwabara Tetsuo,
Yabuzaki Akira
Publication year - 2003
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/0031-8655(2003)0770572rceoam2.0.co2
Subject(s) - viologen , chemistry , photochromism , hexafluorophosphate , alkali metal , dimer , photochemistry , dication , radical ion , electrochromism , ion , inorganic chemistry , organic chemistry , ionic liquid , electrode , catalysis
Two bisviologen derivatives, 1,11‐bis( N ‐propyl‐4,4′‐bipyridinium)‐3,6,9‐trioxaundecane tetrakis‐(hexafluorophosphate) (1) and 1,8‐bis( N ‐propyl‐4,4′‐bipyridinium)‐3,6‐dioxaoctane tetrakis‐(hexafluorophosphate) (2), each incorporating trioxaundecane and dioxaoctane groups between two viologen units, respectively, were prepared so that their photochromic behavior in the absence and the presence of alkali metal ions in a thin polymer film could be investigated. Photoirradiation of the films containing 1 and 2 caused color changes from pale yellow to blue, associated with the photoinduced reduction of the viologen units from the dication to the radical cation. The addition of alkali metal ions, especially, K + and Na + , caused change in the spectra of the photoreduced viologen radical cation for 1 and 2, respectively, because of the increase in the fractional amplitude for the dimer component of the radical cation rather than the monomer one. This may be related to the guest‐induced conformational change of 1 and 2, in which the alkali metal ion is surrounded by the oligo‐oxyethylene unit of 1 and 2. The regulation in photochromic properties of viologen derivatives can be achieved by addition of alkali metal ions.