Symmetrical and unsymmetrical perylene diimides: Their synthesis, photophysical and electrochemical properties

New unsymmetrical perylene diimides have been synthesized to investigate their potential for applications. The symmetrical derivatives of all the compounds have been synthesized for comparison. The compounds are characterized by UV–vis, IR, MS, DSC, TGA and CV measurements. The fluorescence lifetimes, quantum yields and singlet-state energies are presented. All the compounds have very similar fluorescence lifetimes. The LUMO energy values of all the compounds as determined by cyclic voltammetry, are nearly identical. N-substituents have little influence on the electrochemical behavior of all the compounds. The color, solubility, thermal stability, extinction coefficients, aggregation and fluorescence quantum yields are dependent on the nature of the N-substituents. They show different aggregation in solid state.