Ynthesis And Properties Of Metal Complexes Based On Nitro-functionalized Biphenyltricarboxylic Ligands

Coordination polymers have attracted much attention because of their good application value in the fields of luminescence,catalysis,magnetism,adsorption and other functional materials.Nitrotricarboxylic acid ligands have many Coordination sites and flexible coordination modes.They have abundant bridging modes and diverse transmit magnetic coupling behaviors.They can coordinate with metal ions to obtain novel and diverse coordination polymers.Nitro-functionalized biphenyltricarboxylic acid ligands are easy to form coordination polymers with metal ions due to their multiple carboxyl groups.They can be used to identify harmful substances in water and to store information.Auxiliary ligands can also be added to make the structure of the complex more novel and diverse,and make it have more unique magnetic and fluorescent properties.In this paper,a series of complexes with one-dimensional,two-dimensional and three-dimensional structures were constructed by the coordination assembly of nitrotricarboxylic acid ligands with rare earth ions or transition ions.The crystal structure,spectral characterization,infrared and elemental analysis of 19 complexes were carried out.The magnetic and fluorescent properties of some complexes were studied.The research work is mainly divided into three parts:1.Magnetic properties of Ln(III)ions complexes with5-(2-nitro-4-carboxyphenyl)isophthalate Acid5-(2-nitro-4-carboxyphenyl)isophthalic acid(H3L1)is a bifunctional ligand with nitro group and carboxyl group.Its ligand has many coordination modes.It can form carboxyl bridge structure through carboxyl group of ligand,which is conducive to magnetic research.Eight complexes were synthesized with5-(2-nitro-4-carboxyphenyl)isophthalic acid(H3L1)as ligand directly with rare earth Dy(III),Gd(III),Ho(III),Sm(III),Pr(III)metal salts.Among them,five three-dimensional framework complexes with homocrystalline binuclear units were synthesized with H3 L and Dy(III),Gd(III),Ho(III),Sm(III)and Pr(III).Structural characterization and magnetic properties of these rare earth complexes were studied.The binuclear units of the double(?-COO)2 bridge are connected with the L ligand.The magnetic coupling of the double carboxylic acid bridge indicates that the complex 1,3,4 are antiferromagnetic.In zero DC field,3 shows slow magnetic relaxation.Complexes 6,7 and 8 with three-dimensional network structure different from complex 1-5 were synthesized by using H3 L and Dy(III),Gd(III)and Pr(III)ions in different solvents.X-ray single crystal diffraction analysis shows that the structures of complexes 6,7 and 8 are three different three-dimensional structures.6 contains unique linear quadruplex clusters.Three-bond and double-bond carboxylic acid bridges are crosslinked by ligand L skeleton to form a 3D framework.They represent a rare(3,3,12)connection network with dot symbols(43)(43)(421.625.818.102).7 is homogeneous chain units formed by magnetic coupling of one-dimensional chains with(?-COO)2(?2-Ocarboxylate)three-bridge.8 is homogeneous chains formed by magnetic coupling of one-dimensional chains with(?-COO)two double bridges.Unit.Magnetic measurements showed that complex 7 had ferromagnetism,while complex6 and 8 had antiferromagnetism,and complex 8 exhibited slow magnetic relaxation under zero DC field.2.Fluorescence properties of Ln(III)ions Complexes with5-(2-nitro-4-carboxyphenyl)isophthalate AcidIn this chapter,we synthesized a binuclear complex with three-dimensional structure from H3L1 and rare earth Eu(NO3)3 by hydrothermal synthesis.Luminescent sensing experiments show that 9 has high selectivity,good recyclability and low detection limit.It can be used to detect alkylamines in water system.However,the complex can only quench alkylamines fluorescence,and no fluorescence quenching occurs for aromatic amines,anions,cations and organic small molecules.3.Magnetic and Fluorescence Property of Transition Metal ions Complexes with5-(2-nitro-4-carboxyphenyl)isophthalate Acid and 5-(3-nitro-4-carboxyphenyl)isophthalic acidUsing 5-(2-nitro-4-carboxyphenyl)isophthalic acid(H3L1)and5-(3-nitro-4-carboxyphenyl)isophthalic acid(H3L2)as ligand and different transition metals(Co(II),Ni(II),Zn(II),Mn(II)),new coordination polymers with different structural characteristics were synthesized by solvothermal or hydrothermal methods.In the first work,four new compounds of 3D Mn(II)10-13 were synthesized and characterized by using two isomeric dicarboxylic acid ligands.In these compounds,adjacent Mn(II)ions are linked by different carboxylates and ?2-O bridges,resulting in different Mn(II)chains or banded patterns connected by organic spacers into 3D structures.The chain of complex 10 contains two distinct double bridges:(?2-O)2 and(?-syn-anti-COO)2,-ABAB-mode alternating,and complex 11 contains two slightly different double bridges(?-syn-anti-COO)2.3D is composed of alternating dual structure(?-syn-anti-COO)2 bridge and(?-ODMF)(?-syn-anti-COO)(?3-COO)triple bridge of Mn(II)chain.Complex 13 shows a complex 3D network,in which two sets of different units are alternately linked to organic ligands: the bis-carboxylic Acid Bridged Mn(II)chain and the mono-carboxylic acid bridged banded pattern.Magnetic analysis showed that compounds 10,11 and 13 all exhibited weak antiferromagnetic interaction ions between Mn(II).The comparison of magnetic structures shows that the antiferromagnetic coupling of degree 10 and 11 is related to some of them.Previous compounds were mainly located at the distance from Mn to Mn and at the Mn-Ocarboxylate-Mn angle.This work provides a useful strategy to construct flux-based compounds by using tricarboxylic acid ligands and enrich knowledge of magnetic coupling and structure.In the second section,we use H3L1 to react with transition metals Co(II),Ni(II)and Zn(II)under different reaction conditions to obtain metal-organic frameworks of different structures 14-19.In order to enrich the structure of metal-organic frameworks,we add nitrogen-containing heterocyclic4,4'-bipyridine as auxiliary ligands to obtain different structures.Then we study the magnetic properties of 14,15,17,18,19.It is clear that these complexes areantiferromagnetic coupling.