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Redox photochromism in films of viologens and related compounds bearing long-chain alkyl groups

Journal Article · · Chemistry of Materials; (United States)

1,1{prime}-Bis(benzyl or p-methylbenzyl)-4,4{prime}-bipyridinium and trans-4,4{prime}-vinylenebis(1-benzylpyridinium)bis-(p-alkylbenzenesulfonate)s bearing long-chain alkyl groups (viologen Ia,b), prepared from their respective dichlorides by the anion-exchange reaction, were sandwiched between two glass plates by melting to afford thin transparent and mainly isotropic films. These almost colorless or pale yellow films developed intense visible colors by near-UV irradiation, which bleached upon heating (photochromism). This behavior is considered to be due to reversible redox reactions consisting of the one-electron transfer to viologen Ia,b dication from the counteranion by the photon mode (color development) and vice versa by the heat mode (bleaching).

OSTI ID:
7115559
Journal Information:
Chemistry of Materials; (United States), Journal Name: Chemistry of Materials; (United States) Vol. 3:6; ISSN CMATE; ISSN 0897-4756
Country of Publication:
United States
Language:
English