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Creation of Stabilized Electrochromic Materials by Taking Advantage of Azulene Skeletons
Author(s) -
Ito Shunji,
Morita Noboru
Publication year - 2009
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200900393
Subject(s) - cyanine , electrochromism , chemistry , azulene , chromophore , redox , photochemistry , electrochromic devices , combinatorial chemistry , organic chemistry , fluorescence , physics , electrode , quantum mechanics
The preparative scope of the new structural principle of utilization of azulene skeletons as redox‐active chromophores for the production of stabilized electrochromic materials is demonstrated in several examples. The structural principle takes advantage both of the cyanine‐type polymethine dyes and of the violene‐type redox systems. Appropriate combination of cyanine and/or violene substructures will produce at least one cyanine‐type structure in the reduced or oxidized form through an overall two‐electron transfer, although some will produce a cross‐conjugated cyanine‐type structure. Hünig's violene–cyanine hybrid structures, utilizing the bis(enediyne) system, afford electrochromic materials that exhibit strong absorptions in the near‐infrared region in the dianionic state. Cyanine–cyanine hybrid structures, consisting of pairs of cyanine units, show two‐step color changes based on single electron transfer in each step. Combinations of the cyanine and/or the violene substructures permit the design of novel stabilized electrochromic systems, including polyelectrochromic systems. The flexibility of the structural principle is demonstrated by the violene–violene hybrid, violene–cyanine–cyanine hybrid, violene‐cyanine‐violene hybrid, andviolene‐violene‐violene hybrid structures. New examples of the violene‐like redox system with inverse electron demand are provided by 6‐aminoazulene derivatives. The liquid‐crystalline properties of the redox‐active columnar mesogen are revealed by several azulene‐substituted electrochromic materials.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)