5-[2′-氟-4′-溴-苯甲亚胺]-8-羟基喹啉铝的量子化学研究

Quantum Chemistry Studies on Halogen-benzylidene-quinolin-8-ol Alumium Complex

应用密度泛函PBE0方法优化5-[2′-氟-4′-溴-苯甲亚胺]-8-羟基喹啉铝(AlA3)及5-[2′-氟-4′-溴-苯甲亚胺]-8-羟基喹啉(HA)的几何构型,用TDDFT法计算其电子光谱,对电荷转移及金属原子与配体的结合能进行了讨论.计算结果表明:(1)AlA3配合物较稳定,但结合能略低于8-羟基喹啉铝(AlQ3).与AlQ3相比,AlA3的轨道作用较强,静电作用较弱,两者之和相近,但AlA3排斥能较大.(2)计算AlA3的两个电子吸收峰与实验结果相符.AlA3中的电荷由羟基喹啉基团通过Al原子在不同配体间转移呈现出最大吸收峰,属于AlQ3类衍生物的特征吸收峰.因为体系的共轭程度增大使LUMO轨道能降低,电子跃迁需要的能量减少,故吸收峰比AlQ3红移;(3)290 nm吸收峰是电荷由C N基团向羟基喹啉基团转移产生的.在喹啉环接上5-[2′-氟-4′-溴-苯甲亚胺]基团可望制备出波长更长的发光材料,且增加了一个较强的吸收峰.

The geometric configurations of tris {5-[ （2＇-fluoro-4＇-bromo-benzylidene） -amino ] -quinolin-8-ol } aluminum（ AlA3 ） and 5-[ （ 2＇-fluoro-4＇-bromo-benzylidene ） -amino ] -quinolin-8-ol were optimized by PBEO method. The electronic spectra of the complex and ligand were calculated by TDDFT method. It is indicated from the calculation that ： （ 1 ） for the larger Pauli repulsion of ligand, the interaction energy of AlA3 is weaker than that of tris （ 8-hydroxy quinolinato ） aluminum （ AlQ3 ） ; （ 2 ） the maximal absorption wavelength of AlA3, which is assigned to charge transfer between different quinolin-8-ol, is the characteristic band of AlQ3 analogue. The decrease of LUMO energy results in a red shift in electronic absorption spectrum compared to that of AlQ3 ; （3） the 269 nm band is assigned to charge transfer from C = N group to quinolin-8-ol.