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利用最小抑菌浓度(MIC)测定方法对6种含羧基席夫碱的抑菌(主要为大肠杆菌)活性进行了研究。采用密度泛函理论方法 B3LYP/6-31G*基组对6种含羧基席夫碱的抑菌活性进行了计算。结果表明,邻氧乙酸苯甲醛缩氨基酸类席夫碱分子的C N键级越弱,N13上电子云密度越大,HOMO与LUMO之间的能量差(△E)越小,抑菌活性越好,抑菌活性部位主要在C N、—COOH和CH3O—上。丙酮酸缩吡啶甲酰腙类席夫碱分子的C N键级越弱,N6、N8、N10、O15、O14上电子云密度越大,HOMO与LUMO之间的能量差(△E)越小,抑菌活性越好,抑菌活性部位主要在C O、吡啶环和C N上。采用逐步法进行多元线性回归分析,得到线性方程为lg(1/MIC)=2.634-18.08△E-0.006α-3.229 BO C N(n=6,R=0.887,Se=0.237),计算值和实验值基本一致。
The antibacterial (mainly E. coli) activities of 6 kinds of carboxyl-containing Schiff bases were studied by the method of minimum inhibitory concentration (MIC). The antibacterial activities of six kinds of carboxyl-containing Schiff bases were calculated by density functional theory (B3LYP / 6-31G * basis set). The results showed that the CN bond of the benzaldehyde amino acid Schiff base of o-oxyacetic acid was weakened, the electron cloud density of N13 was higher, the energy difference (△ E) between HOMO and LUMO was smaller, and the antibacterial activity was better The main antibacterial activity sites were CN, -COOH and CH3O-. The weaker CN bond of pyracolylhydrazone Schiff base molecule, the larger the electron cloud density of N6, N8, N10, O15, O14, the smaller the energy difference (△ E) between HOMO and LUMO, The better the antibacterial activity, the antibacterial active site mainly in CO, pyridine ring and CN. The multiple linear regression analysis was performed by using the stepwise method, and the linear equation was obtained as lg (1 / MIC) = 2.634-18.08 △ E-0.006α-3.229 BO CN (n = 6, R = 0.887, Se = 0.237) The value is basically the same.