喹唑啉酮类化合物的合成及光电性能

Synthesis and Optical Properties of Quinazolinone Derivatives

以5-溴靛红和2,5-二溴吡啶为原料,合成了2,8-二溴-11H-吡啶并[2,1-b]喹唑-11-酮(Ⅱ),再通过Suzuki偶联反应在分子两侧用三芳胺等供电子基团进行了修饰,合成了3个喹唑啉酮衍生物,收率在68%~85%,其结构经1HNMR、13CNMR和MS确证。通过UV-Vis、FL测试考察了其光学性能,用循环伏安法和理论计算考察了其电化学性质。结果表明:在喹唑啉酮母体分子两侧接入供电子基团延长了分子的π共轭体系,增加了喹唑啉酮母体两侧的空间位阻,减少了分子间的π-π堆积,两侧的供电子基团与喹唑啉酮母体形成了推挽结构,有利于分子内的电子转移,减少电子由基态到激发态的跃迁能,其中接入三芳胺基团的2,8-双(4-(二苯基氨基)苯基)-11H-吡啶并[2,1-b]喹唑-11-酮(Ⅲa)的能带隙(Egap)最小,为2.2533 eV,而未修饰的喹唑啉酮母环(Ⅰ)的能带隙Egap为2.7231 eV。喹唑啉酮化合物的能带隙具有明显优势,该类化合物是一类潜在的三阶非线性光学功能材料。

2,8-Dibromo-11 H-pyrido[2,1-b]quinazolin-11-one(Ⅱ) was synthesized from 5-bromoisatin with 2,5-dibromopyridine. Then three new quinazolinone derivatives with yields between 68% and 85% were obtained via suzuki coupling reaction. These compounds were characterized by NMR and MS. Their optical physical properties were investigated by UV-Vis and fluorescence spectroscopy. Their electrochemical properties were studied by cyclic voltammetry and theoretical calculation methods. The results showed that the introduction of donor groups on the planar structure of parent ring extended the π-conjugation system, reduced the π-π intermolecular stacking of parent ring compound. Furthermore, the formation of push-pull structure by connecting donor groups to quinazolinone backbone not only facilitated the intramolecular electron transfer but also decreased the transition energy of electrons from the ground state to the excited state. Among these compounds, the band gap(Egap) of 2,8-bis(4-(diphenylamino)phenyl)-11 H-pyrido[2,1-b] quinazol-11-one(Ⅲa) with a triarylamine group incorporated was the smallest(2.2533 eV), while that of the unmodified quinazolinone parent ring(I) was 2.7231 eV. These quinazolinone derivatives had obvious Egapadvantages, which were a kind of potential third-order nonlinear optical materials.