Electric field induced second harmonic generation (EFISH) measurements on absorbing compounds: push–pull substituted anilines

Synthesis and Characterization of Dicyanovinyl-Substituted Thienylpyrroles as New Nonlinear Optical Chromophores

“…A reversible process can be attributed to the formation of the radical cation of the pyrrole, whereas the extraction of subsequent electrons gives rise to an irreversible process. Upon dicyanovinylation, the compounds 2a 1 and 2b − e display the first oxidation at about 0.46−0.68 V as a consequence of the destabilizing effect of the electron-withdrawing dicyanovinyl group. 11b,c, As the HOMO levels in the dicyanovinyl-thienylpyrroles 2 increase along the series with the donor strength of the nitrogen substitute in the pyrrole ring, the propensity for oxidation gradually decreases. Cyclic voltammetry shows that the reduction of thienylpyrroles 2 is a reversible one-electron process.…”