A study of the synthesis and nonlinear optical properties of 3-substituted 5H-[1,2,4]triazolo[3′,4′:2,3][1,3,4]thiadiazino[5,6-b]quinoxaline derivatives



*Corresponding author
Department of Organic Chemistry, Faculty of Chemistry, Urmia University, Urmia Iran


3-Alkyl-5H-[1,2,4]triazolo[3’,4’:2,3][1,3,4]thiadiazino[5,6-b]quinoxaline derivatives have been synthesized by the reaction of 4-amino-5-alkyl-4H-1,2,4-triazole-3-thiol and 2,3-dichloroquinoxaline under solvent-free conditions in moderate yields or refluxing in EtOH in the presence of K2CO3 in excellent yields. Third-order, nonlinear optical properties of the quinoxaline derivatives were measured. The replication of linear optics of the new compounds (16a-d) was investigated by UV–Visible techniques in N,N-dimethylformamide as a solvent. The nonlinear absorption coefficient and refraction index of (16a-d) were also measured in N,N-dimethylformamide via a Z-scan method using a continuous-wave, Nd–YAG laser at 532 nm. The nonlinear refraction index was measured from the order of 10-10 m2/W that is caused the compounds appropriate candidate in optoelectronic and electronic modulators and switches. 


The quinoxaline derivatives are an important class of heterocyclic compounds due to their wide range of physical and pharmacological applications.

Third-order nonlinearity in conducting materials is an extremely significant property due to its various applications, including multi-photon and free-carrier absorptions, nonlinearity scattering and refraction (1-2). Heterocyclic compounds, especially quinoxaline derivatives, are widely studied and applied in photonic, optical switching, wave guides, etc (3-4). Hence, the importance of these heterocyclic compounds and their many applications led us to studying the nonlinear optical properties of new synthesized quinoxaline derivatives. Here we report the synthesis of 3-substituted-5H-[1,2,4] triazolo [3’,4’:2,3][1,3,4]thiadiazino[5,6-b]quinoxalines (16a-d). These new compounds were prepared by reaction of 4-amino-5-alkyl-4H-1,2,4-triazole-3-thiol with 2,3-dichloroquinoxaline under solvent-free conditions or refluxing in ethanol in good yields  and their structure is characterized by 1H-NMR, 13C-NMR and FT-IR spectra. T ...