Synthesis,Structures,Optical Properties And DFT Studies Of Metal(Mg,Ca,Sm,Nd) Complexes Containing Octanoyl Amino Carboxylic Acids

Metal complexes have become one of the research hotspots in the field of functional materials because of their tunable coordination structure,large stokes shift,and high photostability.When metal complexes were synthesized,the finiteness of metal ions were combined with the infinite choice of ligands.By selecting appropriate ligands,new metal complexes with novel structures and strong functions can be prepared.Organic carboxylic acid compounds are a kind of commonly organic oxygen-containing ligands.The carboxyl group of carboxylic acid ligands has various coordination modes with various structures through coordination bonds with metal ions.To obtain metal complexes with novel structures and explore the potential use of rare earth metal complexes as luminescent materials,this project selected metal elements(Mg,Ca,Sm,Nd)as the coordination center ions,with three octanoyl amino acids as ligands(H(oct-ala),H(oct-ser),H(oct-phe)).A series of octanoyl amino acid metal complexes were synthesized by solution chemistry.The purity and molecular structure information of the complexes were obtained by elemental analysis,proton nuclear magnetic resonance spectrum analysis,infrared spectrum analysis,and the synthesized samples were determined as the target complexes.The lamellar morphology shapes and amorphous structure with long range disorder of the complexes were characterized by scanning electron microscopy and X-ray diffraction.The optically anisotropic(birefringence)and optically isotropic(single refraction)properties of the complexes were observed by polarized light microscopy,the result shows that some complexes display liquid crystal properties after heating.The thermal performance of the complexes were determined by differential scanning calorimetry and thermal gravimetrydifferential thermal analysis in the temperature range of 0 ??280 ?,the result shows that the complexes have thermal stability.The light absorption properties of the complexes were measured by UV-Vis absorption spectra,the result shows that the complexes have good light absorption in the range of UV-vis light.In addition,the luminescence properties of the rare earth(Sm,Nd)organic complexes were obtained utilizing fluorescence spectra,quantum efficiency,CIE chromaticity diagram,temperature-dependent emission spectra and ultraviolet light irradiation,the result shows that the ligand transferred the absorbed energy to the central rare earth ions through the "antenna effect",resulting in characteristic fluorescence.In addition,based on the experimental research results,the molecular geometric structures,proton nuclear magnetic resonance spectra,infrared vibration spectra of the synthesized octanoyl amino acid metal complexes were studied by density functional theory,and the obtained results were compared with the experimental results.It provides theoretical guidance and supplement for experimental research.