Linear solvation energy relationships. Part 2. Correlations of electronic spectral data for aniline indicators with solvent π* and β values

The solvatochromic comparison method is employed with electronic spectral data to unravel solvent polarity and hydrogen bonding effects on the p→π* transitions of ethyl 4-aminobenzoate, 4-aminobenzophenone, 3,5-dinitro-aniline, 3-nitroaniline, and N-ethyl-3-nitroaniline. Values of b in the solvatochromic equation, ν(i)max=v0+sπ*+bβ are rationalized in terms of indicator HBD (hydrogen bond donor) acidities and solvent-induced rehybridization effects.