Novel fluorescence dyes based on entirely new chromeno[4,3,2-de][1,6]naphthyridine framework

A series of entirely new framework chromeno[4,3,2-de][1,6]naphthyridine derivatives containing triphenylamine groups have been carefully designed and prepared in good yields using the Pd(0) catalyzed Suzuki couplings reactions. The relationship of photoluminescence property and structure of these compounds was systematically investigated via thermogravimetric analyzer, UV–vis, fluorescence and electrochemical analyzer. The HOMO and LUMO distributions of these compounds were calculated by density functional theory (DFT) (B3LYP; 6-31G*) method. These compounds exhibited high fluorescence quantum yields, desirable HOMO levels and high thermal stability, indicating that the combination of chromeno[4,3,2-de][1,6]naphthyridine and triphenylamine could be an efficient means to enhance hole-transporting ability and fluorescent quantum yield.

Graphical abstractEntirely new framework chromeno[4,3,2-de][1,6]naphthyridine derivatives containing triphenylamine groups were synthesized and the optical, electrochemical properties were also investigated. Quantum chemical calculations were used to obtain optimized ground-state geometry, spatial distributions of the HOMO, LUMO levels of the compounds.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Entirely new framework fluorescence dyes based on naphthyridine were synthesized. ► Compounds exhibited efficient emission from blue to green with high quantum yields. ► HOMO/LUMO energy levels were obtained by CV and theoretical calculation. ► The effects of solvents on the fluorescence characteristics were investigated. ► All of the compounds possess of suited HOMO ranges (−5.49 to −5.01 eV).