标题：Synthesis and optical properties of novel pyrido[1,2-a]benzimidazole- containing 1,3,4-oxadiazole derivatives
作者：Yang, H.;Ge, Y.-Q.;Jia, J.;Wang, J.-W.
作者机构：[Yang, H] Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China;[ Ge, Y.-Q] 更多
通讯作者地址：[Wang, JW]Shandong Univ, Inst Organ Chem, Sch Chem & Chem Engn, Jinan 250100, Shandong, Peoples R China.
来源：Journal of Luminescence: An Interdisciplinary Journal of Research on Excited State Processes in Condensed Matter
摘要：A series of novel substituted 1,3,4-oxadiazole derivatives containing pyrido[1,2-a]benzimidazole moiety were synthesized and characterized using FTIR, ~1H NMR, ~(13)C NMR, and HRMS. An efficient tandem reaction was employed as a key step in constructing the pyrido[1,2-a]benzimidazole moiety under very mild condition. The structure of compound 4a was established by X-ray crystallography. The UVvis absorption and fluorescence spectral characteristics of these compounds were investigated in several solvents. Compounds 4ai display similar absorptions, with absorption peaks ranging from 330 to 339 nm in acetonitrile, while the absorption maxima of compound 4j bearing a diphenylamino group on the benzene ring is red-shifted distinctly to 377 nm due to the strong electron-donating property of its substituent and extended π-conjugated system. All these target heterocyclic compounds present blue-green emissions (461487 nm) in dilute solutions and show high quantum yields of fluorescence (Φ_(PL)=0.65-0.99) in dichloromethane.