The Study Of Fluorescent Coordination Complexes With Efficient Selectivity

Conjugated Schiff base complexes is the important contents in the field ofcoordination chemistry. The aim of this research is to synthesize the complexes with goodfluorescence properties and efficient fluorescent selectivity. On the basis of previous studies,we expand some new Schiff base complexes with condensing diaminomaleonitrile ligands.Instead of N,N-(2,4-dihydroxybenzaldehyde) condensing diaminomaleonitrile (H2L1) planeconjugate tetradentate ligand, N,N-(2-hydroxy-1-naphthaldehyde) condensingdiaminomaleonitrile (H2L2) rigid conjugate ligand was designed and synthesized. Bystirring at room temperature and ambient temperature volatile precipitation method, wehave successfully synthesized seven kinds of complexes with H2L1and H2L2ligands. Thecomplexes have been characterized by FT-IR, XRD, elemental analysis, TGA, and X-raysingle crystal diffraction analysis, and fluorescent properties have been also studied. Themain research contents is as follows:1. The complexes (CuL1)·2DMF (1) and (CoL1)·2DMF (2) were synthesized by thereaction of Cu2+, Co2+with H2L1ligand.2. The complexes [ZnL2(DMF)]·(DMF)(3)，[MgL2(H2O)(CH3CH2OH)](4),[CuL2]·2(DMF)(5),[NiL2]·2(DMF)(6), and [CoL2]·2(DMF)(7) were synthesized by thereaction of corresponding metal ions with H2L2ligand.3. Three of these complexes,(CuL1)·2DMF (1),[ZnL2(DMF)]·(DMF)(3), and[MgL2(H2O)(CH3CH2OH)](4) have been studied by the X-ray single crystal diffractionanalysis.4. The fluorescent properties of complexes were studied.(CuL1)·2DMF (1) is withgood fluorescence properties in CH2Cl2and CHCl3, and [ZnL2·(DMF)]·(DMF)(3) and[MgL2·(H2O)(CH3CH2OH)](4) are with good selectivity in common fluorescent solution,while [CuL2·2(DMF)](5),[NiL2·2(DMF)](6) and [CoL2·2(DMF)](7) are not with verygood fluorescence properties. Contrasted the fluorescence properties of these complexes ondifferent metals with ligands, we found the axial position of the complexes with planeconjugate tetradentate ligands is a important control factor of fluorescence properties.Especially in different solvents, these complexes can present different fluorescenceproperties. So M-L2system can be used as a fluorescent probe in many fields.The research results provide significant guidance and valuable reference fordeveloping new molecular fluorescent probes. Based on a detailed investigation of crystal structures, understanding the relationship between the structure and properties providesimportant structural informations for the further design of new fluorescent probes, and laysa good foundation for appling these complexes to environmental monitoring, biosensors,and functional materials in the future.