Theoretical study of photo-physical properties of indolylmaleimide derivatives.
Theoretical study of photo-physical properties of indolylmaleimide derivatives.
复制标题
DOI：
10.1039/c2cp22946c
复制
发表时间：
2012-02
期刊：
影响因子：
--
通讯作者：
Zilong Zheng;Yi Zhao;Manabu Nakazono;S. Nanbu
中科院分区：
文献类型：
--
作者：
Zilong Zheng;Yi Zhao;Manabu Nakazono;S. Nanbu
从理论上研究了溴代吲哚马来酰亚胺（IM-Br）、吲哚琥珀酰亚胺（IS）及其阴离子的光物理性质，并与吲哚马来酰亚胺（IM）的理论结果进行了比较[Phys. Chem. Chem. Phys.，1999]。2010，12，9783]。在cc-pVDZ基组水平上，使用基于二阶瑞利-薛定谔微扰理论（CASPT 2）的多参考微扰计算，计算了这些分子的电子激发态和基态的能量。从分子内电荷转移机理讨论了溴取代引起的吸电子或给电子效应。研究发现，在给电子效应的作用下，溴取代的吲哚NH基一价阴离子（I（（-））M-Br）的自然轨道顺序发生了重排，导致了S（1）和S（2）态势能曲线的赝交叉. I（（-））M-Br的Stokes位移很大，这是由赝交叉引起的。同时，IM和IM-Br显示异常的去质子化，这是由吲哚和马来酰亚胺部分的电荷分布解释。最后，根据溶液中的实验光谱，提出通过吲哚NH端和中性IS去质子化形成的一价阴离子I（（-））M-Br和I（（-））M是最可行的候选阴离子。
Photo-physical properties of bromo-indolylmaleimide (IM-Br), indole-succinimide (IS), and their anions were theoretically investigated compared with the previous theoretical result for indolylmaleimide (IM) [Phys. Chem. Chem. Phys., 2010, 12, 9783]. The energies for the electronic excited states as well as the ground states were computed for these molecules using the multi-reference perturbation calculations based on the second order Rayleigh-Schrödinger perturbation theory (CASPT2) at the cc-pVDZ basis set level. The electron-accepting or electron-donating effect caused by bromine-substitution was discussed in the intra-molecular charge transfer (ICT) mechanism. The order of natural orbitals of the bromine-substituted monovalent anion with a deprotonated indole NH group (I((-))M-Br) was found to be rearranged by the effect of electron-donation, which leads to pseudo-crossing of the potential energy cures of the S(1) and S(2) states. The large stokes shift observed for I((-))M-Br was due to pseudo-crossing. Meanwhile, IM and IM-Br show abnormal deprotonation, which is explained by the charge distribution on the indole and maleimide moieties. Finally, the monovalent anions I((-))M-Br and I((-))M by a deprotonation of the indole NH end and the neutral IS were proposed to be the most feasible candidates corresponding to the experimental spectra in solution.