2 - Formyl -8 - Acetoxy Quinoline Reduction Of Synthesis And Properties Of Aromatic Amine Schiff Base Complexes

Schiff-bases and their metal complexes are widely studied and used in the fields of organic synthesis and coordination chemistry for a number of reasons:their biological, physiological and pharmacological, electrical and photochemical activities. There are many applications of Schiff-bases and their metal complexes, ranging from pure synthetic work to modern analytical, catalytic, physicochemical, biochemical, and material fields. In this paper, we designed, synthesized and characterized nine new Schiff base type compounds containing quinoline unit. Their structures and coordination properties were also studied. This paper includes the following aspects.Chapter I:A brief introduction of researches and applications of Schiff base compounds and their metal complexes is introduced. Then, the recent researches and main developments in the study of 8-hydroxyquinoline derivatives are reviewed. Finally, the importance on the synthesis of new Schiff base type compounds containing quinoline unit is suggested. Chapter II:2-Formyl-8-acetoxyquinoline was prepared by acetylation (acetic anhydrid e) of the hydroxyl group, followed by oxidation (SeO2) of the methyl group, using 2-me thyl-8-hydroxyquinoline as the starting material. Nine kinds of new Schiff base compound s were synthesized by condensation of 2-formyl-8-acetoxyquinoline with substituted anilin es. All the compounds were characterized by IR,UV and 1H NMR.The crystal structures of three kinds of Schiff base compounds were measured by single x-ray diffraction. It is found that the three compounds have similar crystal structures with crystal system being Monoclinic(L1 and L5) and Triclinic(L4) and space group being C(L1 and L5)and P(L4). The quinoline ring and benzene ring are not coplanar, and Schiff base CH=N bond is only coplanar with quinoline ring, which indicate that C=N bond conjugate with quinoline ring only. It is also found thatπ-πstacking interactions are existed between molecules.Chapter III:Forty-five complexes of the newly synthesized Schiff base compounds with transition metal ions were prepared and characterized. The IR spectra show that the vibration of C=N and Ar-O-C of the complexes, compared to Schiff base ligands, changed from 1629-1614cm-1 and 1149-1169cm-1 (before comlexation) to 1611-1597cm-1 and 1110-1089cm-1 (after complexation), respectively. These results show that the nitrogen atom in imine group and oxygen atom in the ester group coordinate to the metal ions. The absorbtions in 525-577cm-1 are designed as the vibration absorption of M-N bonds.The crystal structure of Zn(II) complex of 2-{[(4-bromophenyl)imino]methyl}-8-quinolinol with zinc sulphate was determinated. It is found that the crystal was five nuclear complexes, 2-{[(4-bromophenyl)imino]methyl}-8-quinolinol was tridentate ligand, which uses the nitrogen atoms in the C=N imine group and quinoline ring, and the oxygen in hydroxy group to coordinate with zinc ions.Chapter IV:The studies of antibacterial properties of the newly prepared Schiff base transition metal complexes were carried out, using escherichia coli, aerobacter aerogenes, bacillus subtilis, Proteus, and Staphylococcus aureus. The results show that L1-Cu and L9-Cu complexes are more effective to bacillus subtilis, L1-Cu complex is better to proteus, L1-Cu, L4-Cu and L5-Cu complexes are good to staphylococcus aureus.