Synthesis, characterization, photophysical and electrochemical properties of new thiadiazole-based olefins for OLED applications

Abstract

A three–step synthetic approach was employed to synthesize new thiadiazole-based olefins integrating customized functional groups. This methodology consistently delivered satisfactory overall yields ranging from 44 % to 57 %. Comprehensive structural characterization of the synthesized compounds was conducted using FT–IR and NMR (1H, 13C) spectroscopic techniques. The resulting thiadiazole-based olefins exhibited notable UV absorption (λmax = 309–382 nm). Among these, one compound displayed a green emission, while others exhibited red-orange emission, indicating a Stokes shift ranging from 5423 to 6835 cm–1. Their electrochemical behavior was analyzed, revealing an irreversible redox-active response and experimentally determined HOMO and LUMO energy levels indicated an electrochemical gap of <2.32 eV. Our comprehensive investigation, integrating experimental and theoretical methodologies with TD–DFT calculations, aimed to deepen the understanding of the photophysical properties of the target compounds. This comparative analysis between computational results and experimental data highlights the potential of these N-heteroaromatic compounds as organic small-molecule fluorophores for applications in electroluminescent devices.