3H-1,2-dithiole-3-thione derivatives as novel solvatochromic dyes. 2008, 21, 1007- 1013.

ALEJANDRO M. FRACAROLI; FERNANDO SILVA,; ALEJANDRO M. GRANADOS; RITA H. DE ROSSI

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY

John Wiley & Sons, Ltd.

Año: 2008 p. 1007 - 1013

0894-3230

The UV–Vis spectrum of 5-(1-butylthio)-3H-1,2-dithiole-3-thione (1a) and that of the chromium pentacarbonylcomplex of 5-methyl-3H-1,2-dithiole-3-thione (3) present significant changes with the solvent polarity. The twoabsorption bands shown by the compounds in the region above 300nm were identified by theoretical calculations.For Compound 1a these are n-pi * and pi-pi * transitions and for Compound 3 the longest wavelength absorptioncorresponds to a charge transfer band and shows a remarkably negative solvatochromism. Not only has thewavelength of maximum absorption changed with the solvent but also the ratio of the absorbances at the twowavelengths. The effect of solvents was correlated with solvatochromic parameters such as p* and a. The spectrum of5-(1-butylthio)-3H-1,2-dithiole-3-one (2)Q3 was also measured in different solvents but in this case the changesobserved are less significant than for the other two compounds. The spectra of 1a and 3 were also determined in thepresence of anionic (SDS), cationic (CTAB), and neutral surfactants (Brig-35) and it is shown that these compounds can beused as probes for the polarity of the binding sites of organized assemblies. Copyright 2008 John Wiley & Sons, Ltd.