Synthesis, photophysical and nonlinear optical properties of [1,2,5] oxadiazolo[3,4-b]pyrazine-based linear push-pull systems

Abstract

A series of D-pi-A chromophores based on [1,2,5]oxadiazolo[3,4-b]pyrazine electron-withdrawing group has been designed. The influence of the pi-conjugated linker (1,4-phenylene and 2,5-thienylene) and the amino-electron-donating group (diphenylamino and carbazol-9-yl) was studied by cyclic voltammetry, UV-Vis and emission spectroscopy. The second order nonlinear optical properties were also studied using the electric field induced second harmonic generation (EFISH) method. The experimental results have been rationalized by theoretical DFT calculations.