Synthesis,Characterization And Properties Of New Schiff Base Ligands And Their Cu(?)and Ni(?)Metal Complexes

Schiff base compounds since the discovery,due to its structure of the particularity of the diversity of functions can be a variety of methods for organic synthesis reaction in the system.During the integration process of metal complexes,the complex Schiff base ligands are coordinated with different transition metals to synthesize the transition metal complexes.Schiff base and its transition metal complexes are widely used in agriculture,industry,analytical chemistry,luminescent materials,antibacterial activity and anti-tumor.Therefore,the synthesis method and the properties of novel Schiff base ligands and their corresponding transition metal complexes have become a fascinating research topic.In this paper,o-aminoacetophenone was used as precursor to synthesize the corresponding para-intermediate which named o-aminoacetophenone oxime,and then reacted with 2-Cl benzaldehyde,2-pyrroleformaldehyde,4-cyanobenzaldehyde,2-Naphthyl formaldehyde,salicylaldehyde,3-Br-5-Cl salicylaldehyde and 4-methoxy salicylaldehyde to synthesize the seven Schiff base ligands.Herein,HL1-HL7 are Schiff base ligand which containing a quinazoline structure,respectively:HL1: 2-(2-chlorophenyl)-4-methyl-1,2-quinazoline-3-oxideHL2: 2-(2-pyrrolyl)-4-methyl-1,2-quinazolin-3-oxideHL3: 2-(4-cyanophenyl)-4-methyl-1,2-quinazolin-3-oxideHL4: 2-(2-naphthyl)-4-methyl-1,2-quinazolin-3-oxideHL5: 2-(2-phenyloxy)-4-methyl-1,2-quinazoline-3-oxideHL6: 2-(3-bromo-5-chloro-2-hydroxyphenyl)-4-methyl-1,2-quinazoline-3-oxideHL7: 2-(4-methoxy-2-phenyloxy)-4-methyl-1,2-quinazoline-3-oxide HL8 ligand was synthesized by p-amino acetophenone and tertbutyl ammonium,and then the intermediates were reacted with 5-Cl salicylaldehyde to synthesize the HL8.HL8:1-{4-[(5-chloro-2-hydroxybenzyl)amino] phenyl} ethanone t-butyl oxime.The composition and structure of the ligands were characterized by elemental analysis and nuclear magnetic resonance hydrogen spectroscopy,and the single crystal of ligand HL5 was obtained with the volatilization of the solvent.The coordination reactions were carried out between the Cu(CH3COO)2·H2O,Cu(NO3)2·3H2O,Ni(CH3COO)2·4H2O and the three ligands of HL6,HL7 and HL8,respectively.Four composites of crystals were precipitated through the natural evaporation method.The Cu(II)complex 1 is a three-core crystal structure with five,four,four coordination configurations.Cu(II)complex 2 belongs to tetracyclic mononuclear complex.Cu(II)complex 3 is a mononuclear complex with a five-coordinated configuration.Ni(II)complex crystal is hexahedral mononuclear complex,and the central metal ion is octahedral coordination configuration.The structure and composition of the compounds were determinedby elemental analysis and X-ray single crystal diffraction.The spectral properties of the transition metal complexes and the Schiff base ligand were investigated by infrared spectroscopy and UV spectroscopy.In this paper,the antibacterial properties of HL6,HL7 and HL8 and their complexes against Bacillus subtilis and Escherichia coli were studied with the comparison of antibiotics.