Synthesis, Crystal Structure And Antibacterial Activities Of The Nitrogen Heterocyclic Schiff Base And Their Metal Complexes

In the past decades, the nitrogen heterocyclic Schiff base and their metal complexes have attracted a great deal of attention because of their biological activities and pharmacological properties such as antibacterial,anticancer, anti-inflammatory, antidepressant effects and so on.So it is important for the synthesis and study of organic medicament and functional complexes using the combination of multifunctional nitrogen heterocyclic Schiff base ligands.In order to further enrich and extend the studies on the organic medicament and functional complexes, such as predetermination of molecular architectures and the properties of the complexes, seven novel aromatic nitrogen heterocyclic Schiff base compounds and seven transition metal complexes have been synthesized and characterized by single crystal X-ray diffraction on the basis of the previous work. The crystal structures of the compounds were determined.The antibacterial activities of the compounds and the complexes have also been investigated preliminarily. There are four parts in the thesis.1.The synthesis and biological activity study for Schiff base ligands and their transition metal complexes were introduced.On the basis of which, the research target and method of the paper were put forward.2.Seven nitrogen heterocyclic Schiff base have been synthesized:four Schiff base derived from PMBP, two single Schiff base, one bis-Schiff base, and one unsymmetrical Schiff base, and three pyridine-containing Schiff base.These compounds have been characterized by elemental analysis, IR and X-ray single diffraction, and their crystal structures have been determined.3.On the basis of the ligand of Schiff base H2L, seven Schiff base complexes had been synthesized, these compounds have been characterized by elemental analysis and X-ray single diffraction, and their crystal structures have been determined.The complexes which synthesized by Co2+, Ni2+, Zn2+ Co2+ ions and ligands, respectively have two different structures, and the carboxyl groups is undissociativein in Ag+complexes, these structures indicated that the ligand has abundant coordination modes in these complexes.4.The antibacterial activities of Schiff base and theirs complexes against three kind of bacterias, escherichia coli,staphylococcus aureus and bacillus subtilis were measured, the result indicated they all have better antibacterial activities.The antibacterial activities of Schiff bases derived from PMBP are as follows, compound 1 is better than compound 2,and compound 3 is better than compound 2,and compound 2 is better than compound 4, under the certain concentration.Two of Schiff bases derived from pyridine aldehyde have best antibacterial activities, the largest diameter of inhibiton zone is 2.83 cm, and the complexes of H2L were higher to the ligand.