Study On Synthesis,Characterization,Crystal Structure And Spectral Properties Of Salicylaldehyde-type Schiff Base Ligands And Their Transition Metal Complexes

In this thesis,using 4-aminoacetophenone as raw material,reacting with hydroxylamine hydrochloride,methoxyamine hydrochloride and O-benzylhydroxylamine salt respectively to obtain three kinds of intermediates,and purify them.In the process of intermediate synthesis,it is found that the temperature required for the reaction with different amine hydrochloride salts is different,which directly affects whether the target product can be obtained.Specificially,the reaction with methoxyamine hydrochloride can be carried out at normal temperature,and with hydroxylamine hydrochloride and benzyloxy amine hydrochloride reaction needs to be carried out at a higher temperature.After verification,the reaction is carried out at 60?70?,both the yield and the purity are relatively high,and the extraction must be very careful to prevent subsequent experiments.Then,the obtained intermediates are reacted with salicylaldehyde,5-chlorosalicylic aldehyde,4-methylsalicylic aldehyde,5-methylsalicylic aldehyde to synthesize different Schiff base ligands and analyzed the structures of these ligands by nuclear magnetic resonance instrument.It was found that when synthesizing the ligands,the reaction according to the ratio of intermediate to salicylaldehyde and its derivative is 1:1 to achieve the best results.Besides,in order to prevent the tempreture instability in the process of the reaction,we use water bath constant temperature reaction,but in the water bath reaction should pay attention to the reaction container can not enter the water,otherwise it will directly affect the purity and yield of the reaction product.Since the synthesis of the ligand requires heating,the reaction needs to be carried out under reflux in order to prevent volatilization from reducing the yield.After the reaction is completed,it is further purified by recrystallization and other methods.The obtained ligands are reacted with the transition metal acetates,and the complexes are cultivated by the natural volatilization method.Part of the metal complexes were obtained.The crystal structures of the ligands and its complexes were analyzed and characterized by elemental analysis,infrared spectroscopy,ultraviolet-visible spectroscopy,Hirshfeld surface analysis,and X-single crystal diffraction analysis,and the crystal structures was verified together.Fluorescence experiments show that the fluorescence intensity of the nickel complex is significantly weakened or even quenched compared to the ligand HL¹,while the fluorescence intensity of the zinc complex is significantly enhanced,and the fluorescence of several Cu complexes are higher than that of the ligand All of them show fluorescence attenuation or even quenching,so it can be considered that the ligand HL¹ has certain application value for the recognition of Ni and Zn ions.Six data of crystal structure are collected,which are[Ni?L¹?₂]_n,[Zn?L¹?₂],[Cu₂?L²?₄],[Cu?L³?₂],[Cu?L⁴?₂]and[Cu?L⁵?₂],the crystallographic data are as follows:Complex 1:Empirical formula,C₃₀H₂₄Cl₂NiN₄O₄,Formula weight,634.14,Crystal system,trigonal,Space group,P3₂21,a=13.091?4????,b=13.091?4????,c=16.323?4????,?=90.00°,?=90.00°,?=120.00°,Z=3,V=2422.5?15????³,R₁=0.0450,wR₂=0.1167;Complex 2:Empirical formula,C₃₁H₂₈Cl₂ZnN₄O₅,Formula weight,672.84,Crystal system,monoclinic,Space group,P2₁/n,a=9.9297?13????,b=25.581?3????,c=11.5765?15????,?=90.00°,?=90.348?5?°,?=90.00°,Z=4,V=2940.5?7????³,R₁=0.1111,wR₂=0.2125;Complex 3:Empirical formula,C₉₂H₈₄Cu₂N₈O₈,Formula weight,1556.75,Crystal system,monoclinic,Space group,P2₁/c,a=18.315?2????,b=12.1533?12????,c=17.518?2????,?=90.00°,?=105.289?4?°,?=90.00°,Z=2,V=3761.3?7????³,R₁=0.0659,wR₂=0.1831;Complex 4:Empirical formula,C₄₄H₃₈CuN₄O₄,Formula weight,750.32,Crystal system,monoclinic,Space group,P2₁/n,a=8.0172?13????,b=10.9003?17????,c=42.154?8????,?=90.00°,?=94.749?6?°,?=90.00°,Z=4,V=3671.2?11????³,R₁=0.0483,wR₂=0.1096;Complex 5:Empirical formula,C₄₆H₄₂CuN₄O₄,Formula weight,778.37,Crystal system,monoclinic,Space group,P2₁/c,a=21.6958?8????,b=11.1395?5????,c=7.8561?3????,?=90.00°,?=91.784?1?°,?=90.00°,Z=2,V=1897.74?13????³,R₁=0.0494,wR₂=0.1103;Complex 6:Empirical formula,C₃₄H₃₄CuN₄O₄,Formula weight,626.19,Crystal system,monoclinic,Space group,C2/c,a=36.359?3????,b=10.6723?8????,c=8.0336?7????,?=90.00°,?=100.001?5?°,?=90.00°,Z=4,V=3069.9?4????³,R₁=0.0436,wR₂=0.1076;...