Synthesis and photophysical properties of three ladder-type chromophores with large and rigid conjugation structures

摘要

Three novel ladder-conjugated chromophores indicated as LT1 —LT3 were synthesized and characterized. Further studies on linear, nonlinear optics and electrochemical properties demonstrated their photo-physical features respectively. Compound LT1 shows good two-photon absorption cross-section (δ) up to ~ 1200 CM at 810 nm in tetrahydrofuran, which is attributed to intramolecular charge transfer effect, as supported by density functional theory theoretical calculations. Compound LT2 and LT3 show considerable molar extinction coefficients, which are more than 105, and higher quantum yields. Structure—function relationship is further discussed, suggesting a rational strategy to develop ladder-conjugated small molecules.