以双三苯基膦二氯化钯(Pd(PPh3)2Cl2)为催化剂,通过Stille偶联反应合成二噻吩基苯并噻二唑,将其作为原料分别与5,6二酮-1,10-邻菲罗啉、菲醌、苊醌和联苯甲酰反应,分别制备了4个二噻吩基喹喔啉衍生物(P1、P2、P3、P4)。以无水FeCl3作为氧化剂,4个二噻吩基喹喔啉衍生物通过溶液氧化聚合为4个均聚物。用FT-IR和1 H-NMR等测试手段对单体及聚合物的结构进行了表征。通过UV-Vis-NIR光谱和荧光光谱法,研究了聚合物本征态以及与不同浓度的三氟乙酸(TFA)作用时的光学性能。结果显示,聚合物P2~P4对低浓度TFA具有良好的敏感性,其中聚合物P2与8.0×10-4 mol/L的TFA作用后,P2的CHCl3溶液的颜色发生明显变化,并且其UV-Vis-NIR光谱在600~1 100nm出现新的宽吸收带。P2~P4具有一定的荧光性能,且向溶液中加入一定浓度TFA时,聚合物荧光强度减弱且发射波长发生蓝移,其中聚合物P2与8.0×10-6mol/L的TFA作用时其荧光发射强度明显减弱。
Four dithiophene quinoxaline type monomers (P1,P2,P3,P4) were synthesized by the reaction of dithiophenebenzothiadiazole with 5, 6-dione 1, 10-phenanthroline, phenanthrenequinone, acenaph thenequinone and benzil. Dithiophenebenzothiadiazole was prepared by stille coupling reaction using Pd(PPh3)2C12 as catalyst. Four type polymers were synthesized by oxidative polymerization of dithiophene quinoxaline derivatives using anhydrous FeC13 as oxidant. All monomers and polymers were characterized by FT-IR and 1 H-NMR spectra. The optical properties of polymers solution in CHCI:~, at neutral state and when different concentrations of TFA was added into the solution, were investigated by UV Vis NIR and fluorescence spectrometer. Results show that P2 P4 have good sensitivity to low concentration of TFA, wherein polymer P2 is sensitive to 8.0×10-4 mol/L of TFA. The polymer solution in CHCl3 exhibites sig nificant changes in color and there appears a new broad absorption band in the range of 600 1 100 nm. P2--P4 have certain fluorescence properties, and the fluorescence intensity decreases and emission wave length exhibits blue shift when certain concentration of TFA is added to the polymer solution, wherein polymer P2 has sensitivity to 8.0×10-6mol/L of TFA.