Formation of a leuco Spirolactone from 4-(2-Carboxyphenyl)-7-diethylamino-4 '-dimethylamino-1-benzopyrylium: Design of a Phase-Change Thermochromic System Based on a Flavylium Dye

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A phase-change thermochromic system was designed through the reversible transformation of the 4-substituted flavylium dye 4-(2-carboxyphenyl)-7-diethylamino-4'-dimethyl-amino-1-benzopyrylium into its leuco form, in the presence of a developer (ethyldiisopropylamine) and a suitable solvent (e.g., acetonitrile, n-pentadecanonitrile). The leuco form of the flavylium-based dye is a spirolactone species whose ring opens at low temperature (below the solvent melting point) to form the blue flavylium cation. Decarboxylation of the lactone to give 4-phenyl-7-diethylamino-4'-dimethylamino-1-benzopyrylium was observed upon irradiation of the system with UV light, erasing the thermochromic effect.
Original languageUnknown
Pages (from-to)7760-7766
JournalChemistry-A European Journal
Issue number26
Publication statusPublished - 1 Jan 2010

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