Synthesis, Characterization, Optical Properties and Theoretical Calculations of Blue Light-Emitting 1-Alkyl-2-substituted Benzimidazoles
作者:Hong Shi、Tao Wu、Peng Jiang、Xiao-Dong Jin、Hong-Jun Zhu
DOI:10.14233/ajchem.2013.14025
日期:——
A series of novel blue light-emitting 1-alkyl-2-substituted benzimidazoles (4a-4g) were synthesized by reactions of the 2-substituted benzimidazoles (3a-3e) with ethyl bromide or n-butyl bromide as electrophilic reagent. Compounds 3a, 3c, 3e were synthesized by the condensation of 1a-1c with 1,2-diamino benzene o-phenylene diamine using air as oxidizing agent and compounds 3b, 3d were synthesized by the condensation of 2d-2e with 1,2-diamino benzene o-phenylene diamine using phosphoric acid and polyphosphoric acid as catalyst. Their optical properties were investigated by UV-visible spectroscopy and photoluminescence techniques in solution. They emit violet-blue light (lEmmax = 380-440 nm) with fluorescence quantum yields of 0.43 to 0.92 while diluted in acetonitrile solution. In order to find the relationship between the structures and properties of compounds 4a-4g, theoretical calculations using density functional theory at the B3LYP/6-31g* level were also studied.
一系列新型蓝光发射的1-烷基-2-取代苯并咪唑(4a-4g)通过将2-取代苯并咪唑(3a-3e)与溴乙烷或溴正丁烷作为电亲试剂反应合成。化合物3a、3c、3e是通过将1a-1c与1,2-二氨基苯和邻苯二胺冷凝反应合成的,使用空气作为氧化剂;而化合物3b、3d则是通过将2d-2e与1,2-二氨基苯和邻苯二胺冷凝反应合成的,使用磷酸和聚磷酸作为催化剂。它们的光学性质通过紫外-可见光光谱法和光致发光技术在溶液中进行了研究。在稀释的乙腈溶液中,它们发出紫蓝色光(lEmmax = 380-440 nm),荧光量子产率为0.43至0.92。为了探讨化合物4a-4g的结构与性质之间的关系,还进行了基于密度泛函理论的B3LYP/6-31g*级别的理论计算。