Synthesis,Characterization And Properties Of Salicylaldehyde And N-heterocyclic Ligands And Their Cu(?),Cd(?) Complexes

In coordination chemistry,Schiff base compounds are an essential research subject because of a variety of structures and excellent properties.Among them,salicylaldehyde Schiff base derivatives on account of unique biological activity,so can be used widely in the field of theoretical chemistry,applied chemistry and materials,such as extraction of metallurgical as an analytical reagent,the tire industry adhesion promoter,and so on.In addition,the quinazoline nitrogen-heterocyclic compounds with aromatic ring structure and lack of electron properties,and generally have a high biologically active and low in toxicity.Besides,they can achieve a lower orbital energy and higher electron mobility.Hence,the compounds have a wide range of applications in the pharmaceutical and pesticide production,organic optoelectronic materials.In this paper,five new ligands have been synthesized.Three of them are quinazoline N-heterocyclic ligands,they were synthesized by o-acetophenone oxime and pyridine-3-formaldehyde,4-imidazole formaldehyde and 2-hydroxy-1-naphthaldehyde,respectively.Namely 2-?3-pyridyl?-4-methyl-1,2-quinazoline-N³-oxide?HL1?,2-?4-imidazolyl?-4-methyl-1,2-quinazoline-N³-oxide?HL2?,2-?2-hydroxyl naphthyl-1-yl?-4-methyl-1,2-quinazoline-N3-oxide?HL3?.HL4 and HL5 are salicylic aldehyde schiff base ligands which were synthesised by p-aminoacetophenone t-butyl oxime with salicylaldehyde and 3-methoxy-salicyladehyde,respectively.Namely,1-{4-[?2-hydroxybenzylidene?amino]phenyl}ethanone O-isobutyl oxime?HL4?and 1-{4-[?3-methoxy-2-hydroxybenzylidene?amino]phenyl}ethanone O-isobutyl oxime?HL5?.Then,the ligand structure was determined by elemental analysis,1H NMR and other basic characterization methods.By the ligand HL1 react with Cu?OAc?₂?H₂O and Cd?NO₃?₂?4H₂O,respectively.The single crystals of Cu???and Cd???metal complex were obtained by natural evaporation method.Afterwards,the chemical constitution,structure parameters and space structures were determined by X-ray single crystal diffractometer?XRD?.Cu???complex crystal is anti-symmetrical octa-coordination compounds,center metal ions have two different coordination configurations.Cu1 and Cu2 are tetracoordinated distorted square planar,while Cu3 and Cu4 are pentacoordinated distorted square pyramidal environment,and the metals are bridged by acetate groups.In Cd???complex crystal structure,it is triclinic coordination polymer and has hexa-coordinated distorted octahedral configuration.Nitrate ions participate in the coordination and form a one-dimensional?1-D?chain structure through the coordination bond.Based on the complexes,IR spectra,UV diffuse reflectance spectra and solid fluorescence spectra were characterized by the solubility of the complexes.Moreover,the Cu???complex has been studied by electron paramagnetic resonance spectroscopy?EPR?because of the presence of single electrons of Cu???d9 configuration.Cd???is d10 electron configuration and does not have paramagnetism.The electrochemical properties of Cd???complex are measured by cyclic voltammetry.The antibacterial activity of the ligands and complexes against Gram-positive bacteria?Bacillus subtilis?and Gram-negative bacteria?Escherichia coli?was determined by measuring the size of the inhibition zone by the filter paper diffusion method.At last,the preliminary results of ion recognition of ligands HL1 and HL2 were investigated.