The synthesis, characterization and optical properties of novel 1,3,4-oxadiazole-containing imidazo[1,5-a]pyridine derivatives

• Published in: Journal of luminescence 2011-05, Vol.131 (5), p.1070-1076
• Main Authors: Qing Ge, Yan, Hao, Ben Qian, Yun Duan, Gui, Wu Wang, Jian
• Format: Article
• Language: English
• Subjects: Atomic and molecular physics; Calculations and mathematical techniques in atomic and molecular physics (excluding electron correlation calculations); Chlorides; Density; Density-functional theory; Derivatives; Electronic structure of atoms, molecules and their ions: theory; Exact sciences and technology; Fluorescence; Fluorescence and phosphorescence; radiationless transitions, quenching (intersystem crossing, internal conversion); Imidazo[1,5-a]pyridine; Mathematical analysis; Maxima; Molecular properties and interactions with photons; Molecular structure; Nitrogen-bridgehead; Nuclear magnetic resonance; Oxadiazole; Phenyls; Physics; Synthesis; UV absorption
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2011.01.024

A series of novel substituted 1,3,4-oxadiazole derivatives were synthesized by the reaction of 3-butyl-1-chloroimidazo[1,5-a]pyridine-7-carbohydrazide with propionyl chloride and substituted benzoic chloride in the presence of phosphorus oxychloride. The compounds were characterized using IR, 1H NMR, 13C NMR and HRMS. Absorption and fluorescence spectra were measured in dichloromethane; an intense absorption maxima was noted at ca. 290nm and emission maxima was noted at ca. 470nm. The absorption spectra of the 1,3,4-oxadiazole derivatives reveal that a phenyl and an ethyl group attached to the 1,3,4-oxadiazole ring markedly influenced the maximum absorption. The structures based on density function theory (DFT) calculation show planar configurations for the compounds. The calculated molecular orbital correlates well with their absorption. ► Novel imidazo[1,5-a]pyridine derivatives were synthesized. ► The structures were determined by IR, 1H NMR, 13C NMR and HRMS spectra. ► We investigated the absorption and fluorescence spectral characteristics of the compounds. ► The side group in 1,3,4-oxadiazole ring can affect its photophysical properties markedly. ► Quantum calculation correlates well with their absorption.