The cationic halochromism of phenolate betaines: Molecular dynamics and quantum mechanics studies

Abstract

The cationic halochromism of phenolate betaines was reproduced with the aid of a simple theoretical model, by calculation of the longest wavelength transition energies of supermolecules obtained by positioning a cation M n+ at a variable distance from the oxygen atom of the dye. The theoretical results were compared with experimental data for three systems, Reichardt's betaine 1, Brooker's merocyanine 2 and the N-methyl-8-oxyquinolinium dye 3. The model was validated by molecular dynamics simulations of solutions of dye 3, in methanol and DMSO, in the presence of variable concentrations of Na + .

Raman and Surface Enhanced Raman Signals of the Sensor 1-(4-Mercaptophenyl)-2,4,6-Triphenylpyridinium Perchlorate

“…Pyridinium dyes are an interesting family of compounds due to their synthetic versatility and accessibility, being used as solvatochromic, thermohalochromic and halochromic sensors [1][2][3] . This compounds display poor fluorescent quantum yield; however, they have been employed to synthesize dual probes, spin and fluorescent, when the pyridinium unit is linked to a nitroxide moiety.…”