Structures And Properties Of A Series Metal-organic Frameworks Materials Based On 3,5-bis-(3',5'-dicarboxylphenyl)-1,2,4-triazole

Metal–organic frameworks(MOFs)composed of transition metals and organic ligands by solven(hydro)thermal synthesis in organic solvent.People can by introducing different metal elements and organic ligands,construct a novel structure,excellent performance of complexes.Coordinating diversified and flexible carboxylic acid or nitrogen carboxylic acid ligand,and to design,adjust and modify to achieve versatility,this makes various potential applications in many fields.This dissertation mainly focuses on the hydro(solvo)thermal syntheses,structures and properties of series of coordination complexes based on 3,5-bis-(3',5'-dicarboxylphen yl)-1,2,4-triazole.The thesis is divided into five chapters.The main contents are summarized as below:In the first part,we simply introduced the research progress of Metal-organic frameworks(MOFs).We summarized and highlighted the recent development of the single crystal-to-single crystal(SC-SC)transformation,catalytic and magnetic and fluorescence and supercapacitors performance of MOFs.In addition,the aims and experimental results of this work are also outlined.Secondly,dehydration induced stepwise single-crystal to single-crystal(SC-SC)transformations are observed in two dimensional 63-topological coordination polymer[Co(H2L)(H2O)2]?H2O(1),where H4 L is 3,5-bis(3?,5?-dicarboxylphenyl)-1H-1,2,4-triazole.Upon thermal dehydration at 130°C for 2h,half lattice water in 1 can be released to form[Co(H2L)(H2O)2]?0.5H2O(2).Increase of dehydration temperature to 150 °C for three hours,the third phase [Co(H2L)(H2O)2](3)that is free of lattice water molecule is gained.Further increasing the dehydration temperature to 160 °C for 6 h,one coordination water moleculecan be released,giving rise to dicobalt based 2D(3,6)-connected kgd double layer[Co(H2L)(H2O)](4).During stepwise dehydration SC-SC transformation courses,coordination sphere of Co(II)changes from penta-coordinate trigonal bipyramid to hexa-coordinate octahedra;network topology ranges from 3-connected 63-hcb to(3,6)-connected kgd;magnetism changes from spin canting to intra-dicobalt ferromagnetism.[Co(H2L)(H2O)2]?H2O(1),can effective catalytic Knoevenagel condensation,for DMA in solvent,the temperature of 60°C,which the conversion can reach 98.7%.Thirdly,[Mg(H2L)(H2O)2]·H2O(5),[Zn(H2L)(H2O)2]·H2O(6)and [Zn1.5(HL)(H2O)5]·2H2O(7)have been achieved by hydrothermal synthesis from H4 L ligand with different metal salts.The free H4 L and 5 exhibit emission at 447 nm and 476 nm(?ex = 364 nm),447 nm and 476 nm(?ex = 348)nm in the solid state,respectively,which are usually derived from?*?? transitions.Furthermore,luminescent study indicated that 5 exhibits high sensitivity to electron-deficient nitro-benzene explosives via fluorescence quenching.The luminescent intensity of powder 5 shows an enhancement.Fourth,[Ni(H2L)(H2O)2]·H2O(8),[Co2(L)(4',4-bpy)0.5(H2O)2]·4H2O(10)have been synthezied under hydro(solvo)thermal conditions.SC-SC transformations can be observed of compound 8 by dehydration to generating compound 9,namely [Ni(H2L)(H2O)2].Compound 10 crystallizes in the triclinic space group P-1.Electrochemical properties of 8and 10 are characterized in solid state.Finally,a concise conclusion is summarized and a prospect in this area is drawn.