Synthesis,Structure Regulation And Properties Of Coordination Complexes Based On Flexible Thioether Pyridine Ligands

It has been widespread attention using of flexible thioether ligands with different metal ions to construct complexes and to study the relationship between structure and properties.In this thesis,adopting the mixed ligand strategy,a total of 20 unreported complexes were obtained based on two selected flexible thioether pyridine ligands 1,2-bis[(pyridin-4-ylthio)methyl]benzene(bpb)and 1,4-bis(pyridin-4-ylthio)but-2-ene(bpe).The crystal structures of ligands and all complexes were characterized by single-crystal X-ray analysis.Besides,many analysis methods,X-ray powder diffraction,Hirshfeld surface calculation,infrared spectroscopy,thermogravimetry,photoluminescence properties and so on,were used to characterize the complexes.The main contents are as follows:1.Three complexes were obtained based on bpb ligand,Zn(NO3)2,and different isophthalic acids(1,3-H2bdc,H2mip,and H2tbip),in which 1 and 2 have similar double-layer stacking structure and 3 is a single layer stacking structure.Hirshfeld surface analysis was used to compare the weak sites of different substituents and their effects on crystal structures.Fluorescence spectroscopy studies of complex crystals indicate the presence of inter-layer excitons and intra-layer exciton-related two-channel fluorescence emission in complexes.In addition,the conversion of two homologous fluorescence emissions was studied by mechanical abrasive stripping.2.A series of 1D chain complexes were successfully synthesized by self-assembly of bpb,Cd~? ions,and different substituted isophthalic acids.The effect of substituents on the structure was studied by Hirshfeld surface analysis.The fluorescence spectra of complex crystals showed that there are double fluorescence channels based on ligand luminescence and chain exciton-related luminescence.In addition,time-resolved and variable-temperature fluorescence spectra of all complexes were tested,and the effects of mechanical grinding on the fluorescence of the complexes were studied.3.Four complexes were successfully synthesized by adjusting solvent ratio and controlling temperature using bpb,5-nitroisophthalic acid(H2nip)and Zn(NO3)2.MOF 7 with 1D chain structure,MOF 8 showing a 2D layer,and 3D MOF 10 were obtained by using different ratios of DMF/H2O mixed solvent at 100?.MOF 9 with interlocking structure(2D+2D?3D)was obtained under similar conditions to 10,except that the temperature becomes 110?.The photophysical studies indicate that the relatively narrow optical energy gaps of complexes 7-10 reflect their outstanding semiconductive nature.The photocatalytic degradation of methylene blue by all complexes was studied.4.Four complexes were successfully synthesized using bpb and terephthalic acid under solvent heat condition.Notably,complexes 11 and 12 can be synthesized by changing reaction time,and the ratio of 13 and 14 also can be controlled by that.The single crystal analysis shows that 11 and 14,showing 2D+2D?2D,are heteromorphic,complex 12 displays a 2D net but with 1D channel,and complex 13 is a 1D chain.In addition,the fluorescence spectra of complexes 11 and 12 and the magnetic properties of complexes 13 and 14 were determined.5.Adopting a mixed ligand strategy,six low-dimensional complexes were successfully synthesized based on Zn~?/Cd~? ions,bpe,and different substituted phthalic acids.With the change of substituent of phthalic acids,the structures of complexes 15-17 are successively 2D interpenetrating network(15),2D monolayer network(16),and 1D trapezoidal chain(17),and similar structure transformation from 2D monolayer net(18 and 19)to 1D trapezoidal chain(20)also occurs in complex 18-20.The complex was characterized by powder diffraction and thermal stability,and its fluorescence properties were preliminarily investigated.