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.
A phase-change thermochromic system was designed through the reversible transformation of the 4-substituted flavylium dye 4-(2-carboxyphenyl)-7-diethylamino-4'-dimethylamino-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.
REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
Raquel
R
Gavara
César A T
CA
Laia
A Jorge
AJ
Parola
Fernando
F
Pina
D000097:Acetonitriles / Q000737:chemistry; D000872:Anthocyanins / Q000737:chemistry; D005419:Flavonoids / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D012997:Solvents / Q000737:chemistry; D013148:Spironolactone / Q000138:chemical synthesis* / Q000737:chemistry; D014466:Ultraviolet Rays
C552433:4-(2-carboxyphenyl)-7-diethylamino-4'-dimethylamino-1-benzopyrylium; D000097:Acetonitriles; D000872:Anthocyanins; D005419:Flavonoids; D012997:Solvents; D013148:Spironolactone; C032159:acetonitrile