Synthesis,Crystal Structure And Antitumor Activity Of Copper Complexes With 4-acyl Pyrazolone Schiff Base

4-Acylpyrazolone compounds have a wide range of biological activities such as antibacterial,antitumor and antioxidation and occupy unique position in the field of drug development.In this paper,the structure of 4-acylpyrazolone ligands was optimized by introducing salicylhydrazide,thiophenecarboxylic acid hydrazide and indole-3-acetyl hydrazide with biological activity.Three novel 4-acylpyrazolone hydrazide ligands and their copper complexes were synthesized,and 2,2-bipyridine,1,10-phenanthroline and pyrazino[2,3-f][1,10]phenanthroline were introduced into copper complexes as auxiliary ligands.The structures of ligands and copper complexes were determined by a series of characterization methods and the interaction between HS-DNA and ligands/complexes was studied by UV-visible and fluorescence quenching spectroscopy.And then,the tumor cytotoxicities of the ligands and copper complexes were initially screened by MTT assay.Antitumor mechanism of complexes 4 and 8 which with stronger cytotoxicity were studied.The main research results are as follows:1.Three kinds of 4-acylpyrazolone hydrazide ligands were designed and synthesized,which are N-（1-phenyl-3-methyl-4-（4-fluorobenzoyl）-5-pyrazolone）-2-salicylidene hydrazide（H₂L_a）,N-（1-phenyl-3-methyl-4-（4-fluorobenzoyl）-5-pyrazolone）-2-thiophenecarboxylic acid hydrazide（H₂L_b）and N-（1-phenyl-3-methyl-4-（4-fluorobenzoyl）-5-pyrazolone）-indole-3-acetyl hydrazide（H₂L_c）.Ten copper complexes were obtained by the reaction of the ligand with copper acetate and bpy,phen,dpq,which are[Cu₂（μ-L_a）₂（DMF）₂]（1）,[Cu（L_a）（bpy）]（2）,[Cu（L_a）（phen）]（3）,[Cu（L_a）（dpq）]·CHCl₃（4）,[Cu（L_b）]·CHCl₃（5）,[Cu（L_b）（bpy）]（6）,[Cu（L_b）（phen）]（7）,[Cu（L_b）（dpq）]·CH₃CN（8）,[Cu（L_c）（bpy）]·CH3CN（9）and[Cu（L_c）（phen）]·0.5CH₃CN·CH₃OH（10）.The structure of ligands H₂L_a,H₂L_b,H₂L_cand complexes 1-10 were determined by X-ray single crystal diffraction,elemental analysis and mass spectrometry.It was found that ligands change from keto-form to enol-form during the coordination process and the central metal Cu（Ⅱ）ions of the complexes mainly adopt a five-coordinated tetragonal conical coordination configuration.2.The results of UV-Vis spectra and fluorescence quenching spectra showed that the ligands H₂L_a,H₂L_b,H₂L_cand complexes 1-10 could bind to the salmon sperm DNA（HS-DNA）in different degrees through the insertion mode.It was found that the general trend of DNA binding properties of the complexes was H₂L_bseries copper complexes>H₂L_cseries copper complexes>H₂L_aseries copper complexes.The greater planarity of the co-ligands which involved in the coordination,the stronger DNA binding ability of the copper complexes.The fluorescence quenching constants of complexes 4 and 8 are 6.13×10⁵M^-1and 9.08×10⁵M^-1,respectively,exhibiting excellent DNA binding properties.3.The antiproliferative activities of ligands H₂L_a,H₂L_b,H₂L_cand complexes1-10 against human cervical cancer HeLa cells and human esophageal cancer Eca-109cells were examined by MTT assay.The results showed that copper complexes exhibited excellent antitumor activity compared with ligands and superior to the clinical antitumor drug cisplatin.The overall trend of the antiproliferative effect of the complexes on two types of tumor cells is as follows:H₂L_bseries copper complexes>H₂L_cseries copper complexes>H₂L_aseries copper complexes.Comparing the copper complexes of the same series,it was found that the copper complexes containing the larger planar co-ligand showed better antitumor activity in vitro,and the IC₅₀values of the complex 4 on HeLa cells and Eca-109 cells were 4.37±0.08μM and 3.68±0.14μM,the IC₅₀values of the complex 8 on HeLa cells and Eca-109 cells were 1.92±0.04μM and 1.78±0.09μM.Cell morphology,Hoechst 33258 staining and Annexin-V/PI double staining experiments showed that complexes 4 and 8 inhibited the proliferation of Eca-109 cells by inducing apoptosis in a dose-dependent manner.