Do stilbazolium betaine dyes exhibit inverted solvatochromism by changes in solvent dipolarity?

摘要

The thermochromic behavior of solutions of stilbazolium dyes in dipolar 1-chlorobutane toward a solvent dipolarity change was used for the first time to demonstrate that stilbazolium betaine dyes exhibit inverted solvatochromism, with a bathochromic band shift in the low-dipolarity solvent region and a hypsochromic band shift in the high-dipolarity solvent region. Interestingly, the hypsochromic band shifts of the stilbazolium betaine dyes studied here are twice more sensitive to the dipolarity of the medium than its bathochromic band shifts.