Solvent effects on electronic absorption spectra of 3-N-(4-substituted-phenyl)-5-carboxy uracils

Abstract

Absorption spectra of some 3-N-(4-substituted phenyl)-5-carboxy uracils (substiuents: H, Cl, Br, I, Me, Et, OMe, COOH and NO2) were recorded in twelve solvents in the range 200-400 nm. The effects of solvent polarity and hydrogen bonding on the absorption spectra are interpreted by means of linear solvation energy relationships using a general equation of the form nu=nu(0)+s pi*+b beta+a alpha, where pi* is a measure of the solvent polarity, beta is the scale of the solvent hydrogen bond acceptor basicities and alpha is the scale of the solvent hydrogen bond donor acidities.