2,5-Diaryl-1,3,4-oxadiazoles: synthesis, spectral-luminescent properties, and complexation with beryllium(ii)

Abstract

Cyclization of aroylbenzohydrazides in SOCl2 was used to obtain 2,5-diaryl-1,3,4-oxadiazoles, and to study their spectral-luminescent properties. Oxadiazoles with phenyl or 2-methoxyphenyl substituents at position 2 of the oxadiazole ring have a luminescence with a high quantum yield in polar and nonpolar solvents (λflmax = 378−424 nm, φ = 0.88−0.98). Replacement of these groups with a 2-phenol substituent results in a ligand with strong emission only in highly polar aprotic DMSO (λflmax = 397 nm, φ = 0.18). Based on this ligand, a chelated beryllium complex with the composition L2Be was obtained, which has a strong luminescence in the violet region of the visible spectrum (λflmax = 410−414 nm, φ = 0.34−0.48).