Quinoxaline based amines as blue-orange emitters: Effect of modulating donor system on optoelectrochemical and theoretical properties

Abstract

A series of eight novel donor‒acceptor based quinoxaline‒amine derivatives 2–9 were prepared by modulating donor species on quinoxaline core with Buchwald‒Hartwig coupling amination reaction. The synthesized molecules were fully characterized and studied for impact of D−A interaction on optoelectrochemical properties of derivatives. Absorption spectra of 2−9 display intramolecular charge transfer (ICT) transitions in the range of 377–456 nm. Dyes 2–9 show positive solvatochromism in emission and emit in blue‒orange region with emission maxima 472–592 nm on excitation at their respective ICT maxima in toluene, chloroform, DCM and neat solid film. Herein, dyes 2, 3 and 7 which possess intense emission in solid state were further studied for Aggregation Induced Emission (AIE) effect. The HOMO and LUMO energy level for compound 2–9 obtained by CV were found in the range of −5.23 to −5.83 eV and −3.55 to −3.74 eV. Theoretical studies of molecules were also carried out by using TD‒DFT calculations. The comparable HOMO and LUMO energy level of 2−9 with reported ambipolar materials and efficient solid state emission make synthesized compounds potential candidate for solid state emissive, ambipolar materials in organic electronics.