Spectral studies on some pyrimidine derivatives

The electronic absorption spectra of 2-[2'-Thiopyrimidine]-5-nitro-pyridine [I], 1[2'-Thiopyrimidine]-2, 4-dinitrobenzene [II] 2-[2'-Thiopyrimidine]-1, 3, 5-trinitrobenzene [III] and 3-[[2'-Thiopyrimidine] methyl] benzoic acid [IV] were measured in a series of fifteen different solvents. The solvent effects induced spectral shifts in the different peak locations have been analyzed as a function of different solute-solvent interaction mechanisms. Ground state properties of optimum molecular geometries, singlet-singlet electronic transitions have been calculated using the AM1, PM3, ZINDO/S and ab initio/3-21G methods