Synthesis,Crystal Structure And Luminescent Properties Of Coumarin-Modified-Based Salamo-Like Metal Complexes

Recently,the extensive research on the metal complexes has been received increase attention in the fields of coordination chemistry and organometallic chemistry.With the rapid development of modern coordination chemistry,the syntheses and properties of metal complexes have become major research topics.Salamo-type ligands have good stabilities and flexibilities,and are not easy to hydrolyze,which are easy to coordinate with metal salts to form stable metal complexes.Salamo-type complexes have gradually evolved from mononuclear,binuclear and polynuclear complexes to hetero-metal-polynuclear complexes.So far many novel metal complexes have been prepared.In recent years,Salamo-type metal complexes have potential applications in biological systems,magnetic materials,optical properties,molecular recognitions and other fields.Coumarin,as an important intermediate product and raw materials of organic chemicals,has been widely used in medicine,agriculture,photosensitive materials and other felds.It is noteworthy that coumarin and its derivatives have good characteristics of luminescences and can be used as a good luminescent material.In view of the excellent luminescent properties of coumarins,coumarins derivatives were introduced when the ligand is designed,and their corresponding metal complexes have good luminescent properties.In this thesis,two coumarin-modified salamo-type ligands and their corresponding metal complexes were designed,synthesized,and characterized structurally by elemental analyses,IR and UV-vis absorption spectra.1.Preparation of single salamo-type ligand H₂L¹ and bis?salamo?-type ligand H₄L²H₂L¹ and H₄L² were synthesized using different proportions by the reaction of 4-?N,N-diethylamine?salicylaldehyde or 2,3-dihydroxy-1,4-benzaldehyde and4-methyl-7-hydroxy-8-formyl coumarin.H₂L¹ and H₄L² were structurally characterized by elemental analyses,melting points,IR and UV-vis absorption spectra,which was confirmed that both ligands were target products.The optimum excitation and emission wavelengths of the two ligands were determined by fluorescence spectra.2.Preparation of transition metal complexes based on H₂L¹Mononuclear Cu?II??1?and trinuclear Ni?II??2?complexes were obtained by the ligand H₂L¹ with copper acetate and nickel acetate,respectively,via melting points,elemental analyses,IR,UV-vis absorption spectroscopy and X-ray crystallography.Single crystal X-ray crystallography indicated that abundant hydrogen bonding and C-H...?supramolecular interactions exist in complexes 1 and 2.Clearly,Hirshfeld and two-dimensional fingerprints could observe the proportion of short-range action O···H/H···O,C···H/H···C and H···H in complexes 1 and 2,that is the complexes 1and 2 could be stable.Fluorescence experiments showed that H₂L¹ has a strong fluorescence intensity,while complexes 1 and 2 show relatively weak emission peak.The TG curves of complexes 1 and 2 indicated that the two complexes have different decomposition stages and complexes 1 and 2 have good thermal stability.3.Preparation of transition-rare earth metal complexes based on H₄L²Trinuclear Zn?II??3?and heteropentanuclear Zn?II?-Ln?III??Ln=Eu,Nd,Gd,Dy,Pr??4-8?were obtained by the condensation reaction of H₄L² with transition and rare earth metal salts in different proportions.Complexes 3-8 were characterized by elemental analyses,melting points,UV-vis absorption spectroscopy,IR spectroscopy and single crystal X-ray crystallography.The coordination ratio of transition-rare earth metal and ligand H₄L² could be observed through UV-vis titration experiment.X-ray crystallography indicated the coordination environment and crystal structure of transition and rare earth metals in complex 3-8.At the same time,the crystal structure of complex 4-8 is similar and there are both abundant hydrogen bonding and C-H…?supramolecular interactions.Fluorescence spectra showed that the ligand H₄L²containing coumarin functional groups had strong luminescent intensity.At the same excitation wavelength,complex 3-8 exhibited evidently bathochromic-shift and relatively weak luminescence intensity.Through Hirshfeld and two-dimensional fingerprints,the proportion of short-range interactions O···H/H···O,C···H/H···C and H···H in complex 3 can be clearly observed.