A combined experiment and computation study of the fused polycyclic benzimidazole derivatives.

Novel fused polycyclic benzimidazole derivatives were synthesized from dimethyl 4,5-diaminophthalate/dimethyl 3,4-diaminophthalate with aromatic anhydride (a-b) by condensation. The UV-Visible absorption and fluorescence emission spectra of the dyes were studied in solvents of differing polarity. The dyes were characterized by the spectral analysis. Density Functional Theory computations have been used to derive more understanding of structural, molecular, electronic and photophysical parameters of the push-pull dyes. The computed absorption wavelength values were observed to be in good agreement with the experimental results. The second order hyperpolarizability (β(o)) values were computed by Density Functional Theory and found to be in the range of 67.16 × 10(-31) to 107.76 × 10(-31) e.s.u.