Synthesis and fluorescence of dicyanoisophorone derivatives

A class of dicyanoisophorone derivatives 1–5 with electron-donating groups has been prepared by a two-step condensation reaction. Fluorescence both in solution and in pure solid state are measured. It is found that dicyanoisophorone derivatives 1–5 exhibit fluorescence in both solution and pure solid state. An enhancement of fluorescence in solid state probably results from the aggregation-induced emission. It is also found that dicyanoisophorone derivatives 1–5 show large Stoke's shifts in solution as well as in pure solid state. The origin of fluorescence of dicyanoisophorone derivatives depends on the nature of substituents, with a strong push–pull chromophores dicyanoisophorone system, red or orange solid-state fluorescence is obtained.