6,7,8,9-四氢-吩嗪并[2,3]C_(60)衍生物的结构、电子光谱和二阶非线性光学性质的理论研究

利用半经验AM1量子化学方法研究了6, 7, 8, 9-四氢-吩嗪并2, 3]C60衍生物(1～4)及其异构体5, 6, 7, 8-四氢-9, 10-二氮杂蒽并2, 3]C60衍生物 (5～8) 的结构。 结果表明,目标分子的前线轨道主要由C60部分决定, C60母体与加成基团之间存在较强的分子内电荷转移, C60部分是电子受体,吩嗪环部分为电子给体。 在AM1优化几何构型的基础上, 用INDO/SCI方法计算了目标分子的电子光谱, 用完全态求和(SOS)公式计算了其二阶非线性光学性质。 计算结果表明, 目标分子在400 nm 以上均存在弱吸收峰, 与实验所得结果一致。 5, 6, 7, 8-四氢-9, 10-二氮杂蒽并2, 3]C60衍生物(5～8)的二阶非线性光学系数(0)比其异构体6, 7, 8, 9-四氢-吩嗪并2, 3]C60衍生物(1～4)的大得多。

Theoretical Studies on the Structures, Electronic Spectra and Second-order Nonlinear Optical Properties of 6, 7, 8, 9-4H-phenazino[2,3]C60 derivatives

AM1 semiempirical calculation method was used to study the structures and electronic properties of 6, 7, 8, 9-4H-phenazino2,3]C60 (1~4) and 5, 6, 7, 8-4H-9, 10-diazanthraceno2,3]C60(5~8). The calculated results indicate that the frontier molecular orbitals of C60 moiety dictated those of molecules 1~8. There exists stronger intramolecular electron transfer, with C60 moiety as the electron acceptor while phenazine and anthracene the electron donors. Based on the AM1 geometry optimization, the electronic spectra and second-order nonlinear optical polarizabilities (0) were calculated by using INDO/SCI method combined with sum-over-states (SOS) expression. The calculated results reveal that there exist weak absorption peaks above 400 nm for these C60 derivatives, which agrees with the experimental results. 5, 6, 7, 8-4H-9, 10-diazanthraceno 2,3] C60 (5~8) exhibit more optical nonlinearities than 6, 7, 8, 9-4H-phenazino2,3]C60 (1~4).