| With the continuous design and synthesis of MOFs,as well as its application and development in various fields,MOFs are attracting more and more attention of chemists.In this paper,11 metal complexes were synthesized based on ether-oxygen bond bridged semi-rigid polycarboxylic acid ligands and auxiliary ligands with different transition metal ions,through a series of characterization to study the structure-activity relationship,and analysis of different metal complexes for fluorescence,magnetic properties and electrochemical properties.1.The development,influencing factors and properties of MOFs are outlined respectively.2.Four complexes were synthesized with different transition metal ions under similar reaction conditions by using ether-oxygen-bridged semi-rigid tri-acid ligands2-(4-carboxyphenoxy)terephthalic acid(H3L1)and 4-(3-carboxyphenoxy)phthalic acid(H3L2)as main ligands and 1,10-phen,dib,bix and 4,4'-bipb as auxiliary ligand,namely,[Cd(HL1)(4,4'-bipb)]n(1),[Co(HL1)(dib)(H2O)2]n(2),[Cd3(L2)2(1,10-phen)2·H2O]n(3),[Cd(bix)(NO3)2]n(4).Complex 1 can be regarded as a(2,6)connected three-dimensional topological structure.Complex 2 can be regarded as a two-dimensional topological structure of(2,4)connection.Complex 3 is a one-dimensional chain structure formed by L2 and1,10-phen,which is connected to each other by hydrogen bonds and?···?stacking to form a three-dimensional framework structure.Complex 4 can be regarded as a(2,4)connected three-dimensional interpenetrating topology.Complexes 1 and 3 have good fluorescence properties.Moreover,the complex 1 has a recognition effect on both Fe(III)and Ag(I)ions,in which Fe(III)quenched 1 completely.Therefore,complex 1 is expected to be a fluorescent probe for Fe(III).DFT calculation,2D fingerprinting and Hirshfeld surface analysis were performed for complexes 1-3,respectively.It was found that the short-range interaction on Hirshfeld surface of complexes 1 and 3 was largely due to the H-H/H-H interaction,and for complex 2,it was largely due to the O-H/H-O interaction.It is precisely because of the existence of these short-range interactions that the structure of the complex is more stable.3.A semi-rigid tetra-acid ligand 3-(2,4-di-carboxyphenoxy)phthalic acid(H4L3)bridged by ether-oxygen bond was designed and synthesized.With H4L3 as the main ligand,dib,bix and 4,4'-bipb as auxiliary ligands,five complexes were synthesized with different transition metal ions,namely,[Co2(L3)(bix)(H2O)]n(5),{[Cd2(L3)(bix)0.5(H2O)2]·H2O}n(6),{[Cd2(L3)(4,4'-bipb)2(H2O)]·(H2O)2}n(7),[Zn2(L3)(4,4'-bipb)]n(8),{[Zn2(L3)(dib)(H2O)]·(H2O)2}n(9).Comparing complexes 5 and 6,it is found that the metal ions are different,and the structures of the two complexes are also different.Similarly,comparing complexes 6 and 7,the auxiliary ligand is one of the factors that affect the structure of the complex.Therefore,metal ions and auxiliary ligands have a great influence on the structure of the complex.The comparison of complexes 7 and 8 and the comparison of 8and 9 also verify the above conclusions.Subsequently,the electrochemical and magnetic properties of complex 5 were studied.There is an obvious reduction peak on the CV curve of complex 5,indicating that 5 has a certain energy storage performance.The temperature-varying magnetic susceptibility of complex 5 was studied,and the characterization results showed that there is an antiferromagnetic interaction between the cobalt ions.The complex 6-9 was characterized by fluorescence,and both Ag(I)and Fe(III)had quenching effect on 7,while Fe(III)quenched 7 completely.4.Two diether-oxygen-bridged semi-rigid tetra-acid ligands 3,3'-(1,3-phenylenebis(oxy))diphthalic acid(H4L4)and 4,4'-(1,3-phenylenebis(oxy))diphthalic acid(H4L5)were designed and synthesized.Two complexes were synthesized by H4L4 with 1,10-phen and4,4'-bipb with different metal ions,namely,[Co2(L4)(1,10-phen)2(H2O)]n(10),{[Cd2(L4)(4,4'-bipb)(H2O)2]·(4,4'-bipb)0.5}n(11).The electrochemical properties of complex10 have been studied.The CV curve of complex 10 has an obvious redox peak,which has potential for electrochemical performance.Fluorescence analysis of complex 11 was done,in which Ag(I)ions have a quenching effect on 11,while Al(III)and Fe(III)enhance the fluorescence of 11. |
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