Study On Synthesis And Properties Of Transition Metal Compounds Based On Nitrogen-containing Heterocycles

Since complexes have been studied,transition metal complexes have been one of the hot topics in their fields.Choosing a suitable ligand to coordinate with a transition metal ion can enhance the rigidity of the system,resulting in an increase in the fluorescence intensity of the ligand or a shift in the emission spectrum.This fluorescence characteristic can often be used as a fluorescence sensor to detect solvent molecules,metal cations and some harmful anions.In addition,most transition metal complexes have been found to have antibacterial,anti-inflammatory,and inhibitory effects,especially in binding DNA with potential to be reckoned with.At present,these two aspects have been widely used in the fields of life sciences,food safety and environmental monitoring.Because of its abundant coordination points,stable properties and high absorptivity,pyridine polycarboxylic acid ligands can also chelate or bridge with metal ions to construct metal organic frameworks with various sizes and topologies,which are highly favored in the field of complex research.A novel pyridine polycarboxylic acid target ligand?H₄L¹?with pyridine-2,6-dicarboxylic acid as the terminal group and a benzene ring in the central skeleton was synthesized.The pyridine ring,benzene ring,and carboxyl group in this ligand are all typical?-electron-containing chromophores,which can form a large?-conjugated system,causing absorption and good fluorescence in a certain frequency band Band.When coordinated with metal ions,the ether-oxygen bond in the structure can also be rotated to obtain more novel two-dimensional and three-dimensional structures.Most of the imidazolinone derivatives are very important intermediates for drug synthesis.Their N and O have strong coordination ability and abundant chelating mode.Among them,the 4-acylpyrazolinone derivatives also have keto-and enol-type structural interconversion.Therefore,the complexes formed by 4-acylpyrazolinone derivatives and transition metals not only have structural and luminescence and magnetic properties,but also their biological functions will be more excellent.The content of this thesis is divided into the following three parts:1.The progress of transition metal complexes,especially pyridine polycarboxylic acids and pyrazolinone transition metal complexes at home and abroad were reviewed and the background and significance of this thesis was described.2.A new pyridine polycarboxylic acid ligand?H₄L¹?was synthesized from the starting materials diethyl oxalate and acetone through six-step reaction including Claisen condensation,ammoniation,esterification,substitution,and hydrolysis.A two-dimensional copper coordination polymer was synthesized by hydrothermal method with copper nitrate.The coordination mode and the characteristics of the built spatial structure were discussed,and theoretical calculations?density functional theory calculations and Hirshfeld surface calculations?,biological activity aspects and bacteriostasis studies were performed.3.Based on two 4-acylpyrazolinone derivatives?H₂L²,H₂L³?and their transition metal complexes,the effects of different spatial structures on DNA binding ability were discussed.In order to better understand the electronic transitions in the UV-Vis spectra of ligands and complexes,density functional theory calculations and time-varying density functional theory calculations of these two ligands and their transition metal complexes were performed.Furthermore,the proportion of each interaction in each complex structure is clearly divided by hirshfeld surface calculations.