Synthesis,magnetism And NIR Detection Of Antibiotics Of Three Oxygen Containing Coordination Lanthanide Complexes

Lanthanide ions have potential applications in luminescence and molecular magnetism due to their unique 4f electronic structure.In particular,Nd³⁺and Yb³⁺ions exhibit strong characteristic emission in the near infrared region and Dy³⁺ion exhibit single molecule magnets due to its strong anisotropy,which have attracted the research interest of many scientists.Three kinds of lanthanide complexes were synthesized by selecting three kinds of oxygen-containing organic ligands,the composition and structure of the complexes were characterized and their molecular magnetism and near infrared luminescence detection of antibiotics were further studied.The main research contents are as follows:Though the reaction of N,N’-bis（3-ethoxysalicylaldehyde）-ethane-1,2-cyclohexanediamine（H₂L~1）with lanthanide ions,synthesis of one-dimensional chain structure of lanthanide complexes[Ln（H₂L~1）（NO₃）₃·CH₃CN]_n[Ln=Pr（1）,Nd（2）,Sm（3）,Eu（4）,Gd（5）,Tb（6）,Dy（7）,Ho（8）,Er（9）,Yb（10）].Complexes 2 and 10exhibited excellent NIR characteristic emission and studied for NIR luminescence detection of antibiotics in CH₃CN.The results showed that three nitrofuran antibiotics caused the NIR luminescence quenching of complexes 2 and 10.The NIR luminescence mechanism of the complexes and the detection mechanism of antibiotics were further studied,which is of great significance for the future exploration of NIR luminescence detection.The Yb-based mononuclear complexes[Yb（dmh）₃（bpy）]₂（12）and[Yb（dmh）₃（phen）]（13）were obtained by using 2,6-dimethyl-3,5-heptanedione（Hdmh）as the ligand and introducing auxiliary ligand.And by preparing[Yb（dmh）₃（Me OH）]（11）、[Gd（dmh）₃（phen）]（14）and Yb-phen（15）as the control experiment.The NIR luminescence detection of antibiotics in water by complex 13 with excellent NIR luminescence was studied.The results showed that five kinds of nitro aromatic antibiotics caused complex 13 NIR luminescent quenching,and through the visible region of luminescence peak displacement selective detection of these two kinds of antibiotics,which broadened the research of near-infrared detection of antibiotics in water.Mononuclear lanthanide complexes[Dy（H₂L~2）（NO₃）（CH₃OH）₂][Ln=Dy（16）,Ho（17）,Er（18）]were synthesized by the reaction of N,N’-bis（5-nitrosalicylaldehyde）ethane-1,2-cyclohexanediamine（H₂L~2）with lanthanide ions.The magnetic properties of the complexes 7-9 were studied.The magnetic properties of complexes 7 and 16 are single molecule magnets.The structure-magnetic relationship between the structure and magnetic properties was investigated by the coordination symmetry of central atom,ligand field effect and electron density,which enriched the structure of Salen type lanthanide complexes,single molecule magnets and near-infrared detection of antibiotics.