Very Large Second Order Non-Linear Optical Activity Shown by Heterocycle-Based Dicyanomethanide Zwitterions

Abstract

AbstractThe new series of recently synthesized chromophores 2 - 6 in which a positively charged N-alkylpyridinium acceptor and a negatively charged dicyanomethanide donor are spaced by thiophene-based and/or ethylenic bridging units show dramatically enhanced first molecular hyperpolarizabilities (μβ as high as 27000 × 10−48esu), in comparison with some of the best recently reported neutral systems 7 and 8.