Thermo-solvatochromism of betaine dyes in aqueous alcohols: explicit consideration of the water-alcohol complex

Autor: Omar A. El Seoud, Erika B. Tada, Priscilla L. Silva
Rok vydání: 2003
Předmět:
Zdroj: Journal of Physical Organic Chemistry. 16:691-699
ISSN: 1099-1395
0894-3230
DOI: 10.1002/poc.632
Popis: Thermo-solvatochromism of 2,6-dichloro-4-(2,4,6-triphenylpyridinium-1-yl)-phenolate, 1-methylquinolinium-8-olate and 4-[2-(1-methylpyridinium-4-yl)ethenyl]-phenolate, in the temperature ranges 10–45°C (methanol) and 10–60°C (1- and 2-propanol) was investigated in binary water–alcohol mixtures. Thermo-solvatochromic data were treated according to a modified model that explicitly considers the presence of 1:1 water–alcohol species in bulk solution, and its exchange reactions with water and alcohol in the solvation micro-sphere of the probe employed. Concentrations of these complex species were calculated from density data. Plots of the empirical solvent polarity parameter, ET, versus effective mole fraction of water in the binary mixtures indicate that the probes are preferentially solvated by the alcohol, except for one case. A temperature increase causes gradual desolvation of the probe, due to a decrease in the H-bonding abilities of all components of the binary solvent mixture. Copyright © 2003 John Wiley & Sons, Ltd.
Databáze: OpenAIRE
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