Synthesis And Biological Activity Testing Of Novel Schiff Bases And Their Metal Complexes

1. The preface introduced the recent advances in the synthesis and applications of Schiff bases and their complexes, and the advances of this kind of compounds as potential antibacterial reagents, antiviral reagents, anticancer reagents, enzyme inhibitor, etc. are also reviewed.2. The synthesis and characterization of novel Schiff bases containing pyridine diamide bridge and their complexes were studied.Employing high-dilute method and 5-fold excess amine prepared two new "two-armed" acyclic diamine intermediates I_a and I_b, which are also intermediates of synthesizing microcyclic compounds, and eight aromatic Schiff bases, II_a-h, were synthesized from reaction of I_a or I_b condensing with different aromatic aldehydes. Their composition and structure were characterized by Elemental analysis, IR, UV-Vis, LIF, ¹HNMR and MS. The hydrogen bond interactions and MS fragmental patterns were also discussed.3. Several novel transition metal complexes using II_a as ligand were synthesized and identified by Elemental analysis, IR, UV-Vis, ¹HNMR and molar conductivity. The coordination and deprotonation phenomena were discussed.4. Ten novel rare earth metal complexes using II_e as ligand and eleven rare earth metal complexes using N,N'-bis(2,-hydroxyphenyl-iminoethyl)-2,6-Pyridine dicarboxylic diamide as ligand were synthesized and identified by Elemental analysis, IR, UV-Vis, 'HNMR and molar conductivity. The coordination and deprotonation phenomena were discussed.5. The antibacterial activity of different Schiff bases were tested by microcalorimetric technique.a, An LKB-2277 Thermal Activity Monitor was used to monitor E. coli and S.aureus metabolic activity in vitro to produce thermogenesis curves. The all kinds of parameters of E. coli and S.aureus in different compounds at different concentrations, such as growth rate contants k, half-inhibitory concentration IC50, etc. were deduced from these thermogenesis curves and quantitatively reflected the antibacterial capacity of these Schiff bases compounds.b, Through comparing the antibacterial (E. coli and S.aureus ) capacity of these Schiff bases compounds with different structure, the structure-activity relationship and the general law of antibacterial activity of this kind of compounds were discussed.