Solid state photochromism and thermochromism of two related N-salicylidene anilines

摘要: Abstract The crystalline structure and optical properties of N-salicylidene-p-cyanoaniline N-salicylidene-p-carboxyaniline were investigated in solid state (microcrystalline powder), with the purpose to connect effects substitution crystal packing their properties. Diffuse reflectance fluorescence spectroscopy used study absorption emission upon photoirradiation cooling down liquid nitrogen temperature. Stokes-shifted fluorescence, a quantum yield about 10−2–10−1, is given by tautomeric cis-keto species formed as result excited intramolecular proton transfer from initial enol structure. Despite similar geometrical parameters, only SA-COOH photochromic, which contradiction literature. On other side, thermochromism especially strong at SA-CN. shows behavior SA-CN that classical anil, while presents interesting features contradict presumed based on its supramolecular