新型1，3,4-噁二唑衍生物的合成与性质研究

Synthesis and Properties of Novel 1,3,4-Oxadiazole Derivatives

研制高效载流子传输材料是提高有机电致发光器件性能的关键.采用对酯对二酰氯(5)与含不同链长烷氧取代基的苯甲酰肼(2)缩合制备了一系列腰接羧基1,3,4-噁二唑衍生物,即1,4-二[5-(4-烷氧基苯)-1,3,4-噁二唑基]-2,5-二羧基苯(7;烷氧基=OCnH2n+1;n=8,12,16),并采用UV-vis吸收和荧光光谱对合成物进行了表征.结果表明:7的分子结构中羧基的横向引入,对化合物的光物理性质和能带结构产生较大影响.这些噁二唑化合物的LUMO及HOMO值分别介于-3.62与-3.58eV之间及-6.94与-6.90eV之间,说明它们可能具有良好的电子传输性.

Preparation of high-efficiency carrier transport material is a key to fabricate more efficient and high performance organic and polymeric light-emitting devices. A series of rod-coil 1,3,4-oxadiazole derivatives with lateral carboxyls, 1,4-bis[5-（4-alkoxyphenyl）-1,3,4-oxadiazol-2-yl]-2,5-di（carboxy）benzenes （7; alkoxy= OCnH2n＋ 1; n = 8, 12 and 16） were synthesized by condensation of terephthaloyl chloride （5） with benzohydrazides containing alkoxy chains with different lengths （2）. The results show that introduction of two carboxyls whose electron-accepting ability is stronger reduces the electron density of the conjugated segment of 7, and thus leads to the absorption maximum bathochromic-shift compared to 8 （without carboxyl group）. Calculation on the representative compound by the Dmol^3 package of MS Modeling 3.0 revealed that the decrease of energy levels in 7 was due to the change of the frontier molecular orbital distribution in the central benzene ring because of introduction of two carboxyls. The HOMO and LUMO energy levels of the compounds studied are in the range of -3.62--3.58 eV and -6.94--6.90 eV, which showed that they functioned well as electron-transporting materials.