Based On Zwitterionic Dicarboxylic Acid Ligands Synthesis,Structure And Properties Of Complexes

As a research object of coordination chemistry,complexes have won favor because of their novel structure and wide application.Although the research on coordination chemistry is progressing rapidly,it is still a challenging problem to directionally synthesize complexes with certain functionalities by changing the ligands or metal ions.At present,transition metals and rare earth metals are generally used for the metal ions constituting the complex,and the ligands widely used in the synthesis of complexes are nitrogen-containing heterocycles or carboxyl-containing ligands,and the synthesized complexes can be used for ion/molecule recognition,Adsorption,catalysis,magnetic materials,etc.The zwitterion-containing ligands can provide a good charged environment and strengthen the interaction with the guest molecules,providing conditions for the determination of the follow-up properties of complexes.Based on the above analysis,two different zwitterion-containing dicarboxylic acid ligands 1-carboxymethylpyridine-4-carboxylic acid(CMPC)and l,3-bis(4-carboxyphenyl)-imidazole[H2(IMS1)Cl]were designed and synthesized.By reacting them with transitional/rare earth metals,18 complexes have been successfully synthesized,11 of which are structurally different,and their structures and properties have been analyzed and studied.The following is the specific content of this paper:1.The use of a primary ligand of pyridine dicarboxylic acid,l-carboxymethylpyridine-4-carboxylic acid(CMPC),and an ancillary ligand(2,2-dipyridyl,1,10-phenanthrene and 4,4-dipyridyl)react with the transition metal salt Cd(NO3)2·4H2O,respectively,to synthesize three complexes with different structures[Cd(CMPC)2(H2O)4]n(1),{[Cd(CMPC)2(1,10-phen)]·7.54H2O}n(2),{[Cd(CMPC)2(H2O)]·2H2O}?(3).According to the crystallographic software analysis,finding that only the 1,10-phenanthroline ligand in complex 2 participated in the coordination,but the structures of the three complexes were completely different.Complex 1 is a 3D hydrogen-bonding supramolecular structure.The complex 2 passed the ?-? stacking action forms a two-dimensional layered structure,while the complex 3 presents a three-dimensional framework structure with {65·8} topology.It is worth noting that although 2,2-bipyridine and 4,4 dipyridyl do not participate in the coordination,the differences in structure indicate that the N-donor-containing ancillary ligand has an effect on the structure of the complexes.We measured the fluorescence properties of complex 2.2.We designed and synthesized a second ligand,1,3-bis(4-carboxyphenyl)-imidazole[H2(IMS1)Cl].Coordinated with transition metal(Cd,Cu,Zn,Pb,Hg)and lanthanide rare earth metals(Ln?La,Pr,Eu,Tb,Ho,Er,Yb),fifteen complexes were successfully synthesized:{[Cd2(IMSl)]Cl·2H2O}n(4),{[Cd(IMS1)2]·2.46H20}n(5),{[Cu(IMS1)H2O]NO3 H2O}n(6),{[Zn(IMSl)2]·10H2O }n(7),{[Pb(IMS1)]·1.29H2O}n(8),{[Hg(IMS1)N3]·0.5MeOH}n(9),{[Tb(IMS1)(SO4)]·2H2O·CH3CN}n(10),{[Ln(IMS1)2]Cl·4H2O}n(11-17)(Ln=La,pr,Eu,Tb,Ho,Er,Yb).Crystallographic software analysis revealed that complex 4 used two ?-Po-type cubic structures interpenetrated to eventually exhibit a three-dimensional double interpenetrating structure.Complex 5 was passed through six monolayer chains and the two structures are interpenetrating to form a three-dimensional six interpenetrating structure.The complex 6 is connected by the formed two-nuclear metal clusters to form a single-layered network structure,and eventually exhibits a three-dimensional double interpenetrating structure through multi-layer interpenetration.The complex 7 also shows a three-dimensional double interpenetrating structure by several layers of chain structures extending indefinitely to the periphery.The complex 8 forms a helical tubular structure on the ac plane,and the four tubular structures interpenetrate to form a three-dimensional four-fold interpenetrating structure.Complex 9 is connected by intramolecular and intermolecular hydrogen bonding to form a three-dimensional double interpenetrating structure.Complex 10 forms a three-dimensional network structure by intermolecular hydrogen bonding.The complexes 11-18 have the same structure.They all use metal clusters La2(CO2)8 as four-nodes,presenting a three-layer interpenetrating three-dimensional network structure.After that,the infrared and thermostability of the complex 4-11 were measured.At the same time,the complex {[Eu(IMSl)2]Cl·4H2O}n(11)has good luminescence properties.The determination of the ion-recognition properties led to the conclusion that the complex 11 has a good recognition of Fe3+.