新型双噻吩衍生物的合成、晶体结构及光谱性能

通过Suzuki偶联反应,用不同基团对双噻吩原料上的溴原子进行取代后合成了一系列双噻吩衍生物:3-(5′-溴-2,2-双噻吩]-5-基)吡啶(Dt-1)、5,5-双(吡啶-3-基)-2,2-双噻吩(Dt-2)、5-(3,5-双(三氟甲基)苯基)-2,2-双噻吩(Dt-3)、5,5-双(3,4,5-三氟苯基)-2,2-双噻吩(Dt-4)。通过红外光谱(IR)、质谱(MS)、核磁共振氢谱(1H NMR)及单晶X射线衍射对其结构进行了表征。通过紫外-可见吸收光谱和荧光光谱研究了其发光性能。结果表明,在CH2Cl2溶液中,化合物Dt-1在349 nm激发光作用下在390~470 nm区域有较强的双荧光发射行为,两个最大发射峰分别为403 nm和422 nm;化合物Dt-2在372 nm激发光作用下在400~480 nm区域即紫色和蓝色光区有较强的双荧光发射行为,最大发射峰分别为430 nm和440 nm;化合物Dt-3在349 nm激发光作用下在418 nm处有最强的荧光发射;化合物Dt-4在371 nm激发光作用下于436 nm处有最强的荧光发射。由于双噻吩共轭结构中引入的吸/给电子基团增加了π电子的流动性以及共轭程度,增强了分子间的相互作用力,振动弛豫现象以及斯托克斯位移(Stokes shifts)的产生引发的能量损失导致最大吸收峰向长波方向移动。

Synthesis,Crystal Structure and Spectroscopic Properties of Novel Bisthiophene Derivatives

A series of bisthiophene derivatives were synthesized by Suzuki coupling reaction,in which bromine atoms on bisthiophene raw materials were substituted with different groups:3-(5′-bromo-2,2-bisthiophene]-5-yl)pyridine(C13H8BrNS2,Mr=322.24,compound Dt-1),5,5-bis(pyridine-3)-yl)-2,2-bisthiophene(C18H12N2S2,Mr=320.43,compound Dt-2),5-(3,5-bis(trifluoromethyl)phenyl)-2,2-bisthiophene(C16H8F6S2,Mr=378.35,compound Dt-3),5,5-bis(3,4,5-trifluoro-phenyl)-2,2-bithiophene(C20H8F6S2,Mr=426.39,compound Dt-4).The structures were characterized by infrared spectroscopy(IR),mass spectrometry(MS),nuclear magnetic resonance spectroscopy(1H NMR)and single crystal X-ray diffraction.The luminescence properties were studied by UV-Vis absorption spectroscopy and fluorescence spectroscopy.The results showed that compound Dt-1 had strong fluorescence emission ranging from 390 nm to 470 nm under the excitation light of 349 nm in CH2Cl2 solution,and the two largest emission peaks are 403 nm and 422 nm,respectively.Compound Dt-2 showed strong fluorescence emission in the 400-480 nm region under the excitation light of 372 nm with two maximum emission peaks at 430 nm and 440 nm.Compound Dt-3 exhibited the strongest fluorescence emission at 418 nm under excitation light of 350 nm and compound Dt-4 presented the strongest fluorescence emission at 436 nm under 371 nm excitation light.Due to the introduction of electron-withdrawing/donating groups in the conjugated structure of bisthiophene,the mobility and conjugation degree ofπelectrons are increased,and the intermolecular interaction force is enhanced.Energy loss caused by vibration relaxation phenomenon and Stokes shift leads to the shifts of the maximum absorption peaks to the long wave direction.