黄曲霉素B1及异构体的前线轨道与拉曼光谱研究

采用B3LYP混合泛函和6-311+g(d, p)基组，利用DFT密度泛函理论优化得到了黄曲霉素Aflatoxin B1(cis)(AFB1(cis))及其反式异构体分子AFB1(trans)的稳定结构, 通过单点能计算和几何结构分析，其顺式结构比反式结构更加稳定;计算了两种分子的Raman光谱，并与AFB1(c)粉末的实验Raman光谱进行比较，吻合较好。把最强的三个峰1 582，3 065和1 626 cm-1指认为顺式结构的特征峰，把1 616，3 065和1 659 cm-1指认为反式结构的特征峰;在优化计算的基础上采用Hirshfeld原子划分方法结合Multiwfn软件分析了前线轨道成分，两种分子的亲电能力明显强于其亲核能力，通过计算C1原子在LUMO轨道中的占据权重分别为21.48%和20.62%，预测出C1原子是这两种顺反异构分子夺走DNA中的电子致癌的最主要位点。结果对该类顺反异构分子的检测、转化以及毒性抑制方面具有一定的理论指导意义。

Study on the Frontier Orbital and Raman Spectra of Aflatoxin B1 and Isomer

Through computation, this paper obtained Aflatoxin B1 and its trans-isomer molecules stable structure which was rarely reported by the density functional theory(DFT) with B3LYP complex function and 6-311+g(d, p) basis set. Through a single point calculations and geometry analysis, we know that the cis -structure is more stable than trans-structure. On the basis of this, Raman spectra of two molecules are calculated by the same method and basis set. compared with the Aflatoxin B1 cis -structure powder experimental Raman spectra, it was informed that numerical results with experimental results combined with a better. While 1 582, 3 065, 1 626 means to take the strongest of the three peaks of cis-structure raman characteristics, 1 616, 3 065, 1 659 cm-1 is indicated for the strongest of the three peaks of trans-structure raman characteristics. Use the Hirshfeld atom division method combined with Multiwfn software to analyze the composition of frontier orbital based on optimization calculation, and it was informed that the electrophilic ability of two m on olecules was stronger than the nucleophilic ability. The proportion of C1 atoms in LUMO orbital are respectively 21. 48 percent, 20. 62 percent by calculating, thus it is predicted that C1 atom is most main position spot depriving of the electronic in DNA to cause cancer. The above-mentioned research has certain theoretical directive significance in detection，transformation and toxicity inhibition of the cis-trans isomers.