5-[2'-氟-4'-溴-苯甲亚胺]-8-羟基喹啉铝的量子化学研究

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CN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.

Quantum Chemistry Studies on Halogen-benzylidenequinolin-8-ol Alumium Complex

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 PBE0 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 CN group to quinolin-8-ol.