Multistate/multifunctional behaviour of 4'-hydroxy-6-nitroflavylium: a write-lock/read/unlock/enable-erase/erase cycle driven by light and pH stimulation.
We have investigated the network of reactions observed for the photochromic 4'-hydroxy-6-nitroflavylium compound in aqueous solutions upon pH changes (including pH jump and stopped flow experiments) and light excitation. The changes observed in the NMR and UV/Vis spectra allowed identification of ten different forms in which this compound can be transformed depending on the experimental conditions. Equilibrium and kinetic constants have been determined. Compared with other members of the flavylium family, 4'-hydroxy-6-nitroflavylium is characterized by a large cis-->trans isomerization barrier, and a very efficient hydration reaction. These peculiar features allow writing, reading, storing and erasing photonic information on 4'-hydroxy-6-nitroflavylium by a novel cyclic process that involves the following steps: write-lock/read/unlock/enable-erase/erase.
Moncada
Margarida C
MC
Departamento de Química, Centro de Química-Fina e Biotecnologia-REQUIMTE, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Monte de Caparica, Portugal.
Parola
A Jorge
AJ
Lodeiro
Carlos
C
Pina
Fernando
F
Maestri
Mauro
M
Balzani
Vincenzo
V
D000098:Acetophenones / Q000737:chemistry* / Q000528:radiation effects*; D000475:Alkenes / Q000737:chemistry* / Q000528:radiation effects*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008027:Light; D015394:Molecular Structure; D009574:Nitro Compounds / Q000737:chemistry* / Q000528:radiation effects*; D010084:Oxidation-Reduction; D010777:Photochemistry; D013237:Stereoisomerism
C495930:4'-hydroxy-6-nitroflavylium; D000098:Acetophenones; D000475:Alkenes; D009574:Nitro Compounds