Electronic Spectrum of different Bis-Schiff bases of Isatin and its Solvatochromism

The influence of a series of organic solvents on the UV spectra on some selected bis-Schiff base derivatives has been studied in a number of organic solvents with diverse polarities. As a part of our efforts to interpret the effects of solvent polarity and hydrogen bonding on the absorption spectra of previously synthesized bis-Schiff base derivatives, the study design was based on the linear solvation energy relationship (LSER) concept using Kamlet-Taft solvatochromic parameters: π*, α and β. Correlation of spectroscopic data was carried out by means of multiple linear regression techniques. The fitting coefficient obtained from this analysis allows estimating the contribution of each type of interactions relative to total spectral shifts in solution. The dependence of (u_max) on the solvent parameters indicated that the obtained bands were affected by specific and nonspecific solute-solvent interactions.