Characterization,Spectroscopic,and Electrochemical Properties Of Quinazoline Ligands And Schiff Base Cu(?) Complexes

Quinazoline is a compound of fused heterocycles,which is considered as an important chemical composition with a variety of physiological meaning and pharmacological uses.On the side,quinazoline ligands have shown a wide range of biological activities in animals as well as humans,such as anti-HIV,anti-mutagenesis,anti-convulsion,central nervous system inhibitors,anti-aging activities.Therefore,the study of quinazoline derivatives provides a valuable reference in the future.In the past several years,Schiff bases have become strong chelating ligands in coordination chemistry because of their ease of synthesis,structural changes as well as several biological,catalytic and industrial applications,especially the copper complexes rooted in Schiff bases have been widely studied attribute to their vast applications in ingredient and biological production science.Firstly,this thesis introduces the synthesis of the intermediate 2-aminoacetophenone oxime and reacted with 4-cyanobenzaldehyde,4-nitrobenzaldehyde,salicylaldehyde,2-hydroxy-4-methoxybenzaldehyde to synthesize HL₁-HL₄,the ligand HL₅ was obtained from the intermediate 4-aminoacetophenone oxime with piperonal.HL₁:2-?4-cyanophenyl?-4-methyl-1,2-dihydroquinazoline 3-oxide;HL₂:2-?4-nitrophenyl?-4-methyl-1,2-dihydroquinazoline 3-oxide;HL₃:2-?2-hydroxyphenyl?-4-methyl-1,2-dihydroquinazoline 3-oxide;HL₄:2-?2-hydroxy-4-methoxyphenyl?-4-methyl-1,2-quinazoline-N³-oxide;HL₅:1-?4-??Benzo?dioxol-5-ylmethyleneamino?phenyl?ethanone oxime.The organic ligands HL₁?HL₅ were characterized by various means to determine the structures,such as elemental analysis,¹H NMR,IR,etc.The single crystal of the ligand HL₅was also gained.HL1,HL2 as primary ligands and 1,10-phenanthroline as secondary ligand react with Cu?NO3?2?3H2O to obtain Cu?II?complexes 1 and 2,respectively.Complex 3 has been synthesized via complexation of Cu?II?nitrate trihydrate with 1,10-phen.The chemical structures of the crystal were determined by X-ray single crystal diffractometer.The Cu?II?complexes 1-3 are all in penta-coordinated,in which 1 and 2 are nitrate ions participating in the triangular bipyramid configurations and 3 is also centered on Cu?II?.Cu?II?complex 4 is a crystal with binuclear molecular structure obtained by the reaction of ligand HL₃ with Cu?NO3?2?3H2O to obtain a eight coordination configuration.The UV-Vis absorption of the ligand HL₅ and all complexes as well as the bacteriostatic activities and electrochemical properties of Cu?II?complexes 1,2 and 4 were tested,which were compared with the corresponding ligands HL₁?HL₃,meanwhile the electron paramagnetic resonance spectroscopy?EPR?of binuclear Cu?II?complex 4 were investigated.In addition,the density functional theory?DFT?,Hirshfeld surfaces analysis and Fingerprint plots were used to theoretically study the complexes 1–4 and the ligand HL₅,the molecular orbital energy and band gap values were calculated;the time-dependent density functional theory?TD-DFT?calculation of the adiabatic complexes 1–4 and ligand HL5 further clarifies the effect of electronic transition on the UV-visible absorption spectrum;the Electrostatic Potentials?ESP?analysis was utilized to visualize the charge distribution on the molecules,and the mapping demonstrated the reactive sites of four complexes the ligand HL5,which confirmed the observation of the optimized structure formed in the crystals by hydrogen bonds.