5-氯甲基水杨醛缩苯丙氨酸过渡金属(Ⅱ)配合物的合成及抗菌活性

Synthesis and Antibacterial Activities of Transition Metal(Ⅱ) Complexes of 5-(Chloromethyl)Salicylaldehyde-Phenylalanine

在乙醇溶剂中合成5-氯甲基水杨醛缩苯丙氨酸新型Schiff碱配体及其过渡金属M(M=Mn2+、Co2+、Ni2+、Cu2+、Zn2+)配合物.通过元素分析、摩尔电导、红外光谱、紫外光谱及差热-热重方法对其组成和结构进行了表征.采用滤纸片法和试管二倍稀释法试验测定了Schiff碱及其过渡金属配合物对大肠埃希菌Escherichia coli和金黄色葡萄球菌Staphylococcus aureus的抗菌活性.结果表明Schiff碱配体为1∶1型电解质,其组成为KHL.H2O(L=C17H14O3NCl2-);合成的5种Schiff碱金属配合物均为非电解质类型,组成为[ML(H2O)].nH2O,配体L中的亚胺基氮、酚基氧、羧基氧均与中心金属离子M配位,另有1个水分子参与配位.荧光光谱试验显示,5种配合物的荧光强度均较相应Schiff碱配体的明显增强,其中锌配合物的荧光强度最大.体外抗菌试验结果表明该Schiff碱配体及其过渡金属配合物都具有一定的抗菌活性,而且配合物的抗菌活性强于Schiff碱配体,其中铜配合物对大肠埃希菌和金黄色葡萄球菌均表现出最强的抗菌能力,其对这2种细菌的最低抑菌浓度(MIC)分别为25.0和12.5μg.mL-1.

A novel Schiff base, 5- （chloromethyl） salicylaldehyde-phenylalanine, and its transition metal （ Mn2 ＋, Co2 ＋, Ni2 ＋, Cu2 ＋, Zn2 ＋ ） complexes were synthesized in ethanol. The ligand and complexes were characterized by elemental analysis, molar conductance measurement, IR, UV and TG-DTA, and their anti- bacterial activities were detected by paper-disc method and the double-dilution-method. The results showed that the Schiff base was the electrolyte of 1：1 type with the formula of KHL · H2O（ L = C17 H1403NC12-） and these five complexes were the noneleetrolytes with the formula of [ ML（H20） ] · nH2O. The nitro- gen atom of imino group and the oxygen atoms of phenol group and earboxyl group in the ligand and one water molecule were coordinated with the central metal. The fluorescence experiments showed that the fluorescence intensity of each complex was higher than that of the Sehiff base, and the zinc complex had the highest fluorescence intensity. The in vitro antibacterial experiments exhibited that all of the Schiff base and the complexes had antibacterial activities and each complexe had a higher antibacterial activity than that of the Schiff base. The copper complex had the highest antibacterial activity against Escherichia coli and Staphylococcus aureus and its minimal inhibitory concentrations （MIC） against these two bacteria were 25.0 and 12. 5 μg · mL-1 respectively.