SYNTHESIS AND CHARACTERIZATION OF THIOPHENE-CONTAINING CHROMOPHORES FOR NONLINEAR OPTICAL (NLO) MATERIALS

A series of chromophores based on benzene and thiophene moieties as pi-conjugating spacers were designed and synthesized by Horner-Emmons-Wadsworth reaction and Vilsmeier-Haack reaction, followed by Knoevenagel reaction with different electron acceptors. Their structures were confirmed by (HNMR)-H-1, FT-IR, HPLC-Ms, UV-visible spectra, and the thermal properties were characterized by differential scanning calorimetry (DSC). Solvatochromic method was used to measure their nonlinear optical properties. The variation of chromophoric structures on NLO properties was investigated, indicating that the cyano substitution on the vinylene bridge of the chromophore produces a considerable red-shift of the absorption maximum, and would greatly enhance the molecular quadratic hyperpolarizability (beta mu).