Synthesis,structure And Fluorescence Properties Of 4,4'-thiobis(Methylene) Dibenzoic Acid Coordination Polymers

Coordination polymers are usually composed of oxygen and nitrogen containing multidentate organic ligands and metal ions through self-assembly to form organic and inorganic hybrid materials with one-dimensional,two-dimensional or three-dimensional structures.Because of its potential application value in luminescence,catalysis,gas storage and adsorption,etc.,Scientific researchers are paying more and more attention to its synthetic development.During the synthesis of the coordination polymer,the rigidity and flexibility of the ligand can form different spatial structures with the central metal ion from different angles.In this paper,a flexible aromatic polycarboxylic acid sulfide ligand 4,4'-thiobis(methylene)dibenzoic acid[H2tmba]was synthesized,with flexible H2tmba as the main ligand and rigid 1,10-phenanthroline(Phen)Solvent-thermal synthesis of four new coordination polymers for auxiliary ligands and transition metals:[Co2(tmba)2(Phen)2(H2O)]n(1),[Ni2(tmba)2(Phen)2(H2O)]n(2),[Mn(tmba)(Phen)]n,(3)and[Zn(t mba)(Phen)]n(4).Compound 3 has a two-dimensional network structure,and compounds 1,2,and 4 have a one-dimensional chain structure.By changing the pH value of the mixed solvent of water and N,N-dimethylformamide(DMF),a series of new three-dimensional coordinations have been synthesized under weak alkaline conditions with H2tmba as the main ligand,Phen as the auxiliary ligand and lanthanide metal.Polymer[Ln4(tmba)6(Phen)5(H2O)4]n[Ln=Ce(5),Pr(6),Nd(7),Sm(8),Eu(9),Tb(10),Dy(11)].The compound structure was studied by X-ray single crystal diffraction,elemental analysis,infrared spectroscopy,X-ray powder diffraction,and thermogravimetric analysis.X-ray single crystal diffraction results show that compound 1-2 is a crystallographic isomorphism and belongs to the monoclinic system,I2/a space group;compound 3 crystallizes in the monoclinic system,P2/c space group;compound 4 belongs to the monoclinic system,P21/n space group;Compounds 5-11 are crystallographically isomorphic and all belong to triclinic crystal system,P-1 space group.The four Ln(?)central ions in the asymmetric structural unit form[Ln2(COO)4]2+secondary structural unit(SBU)and bridge with the H2tmba ligand to form a one-dimensional chain structure through the ligand tmba2-infinitely extends along the bc plane to form a two-dimensional network structure,and tmba2-ligand is further bridged to form a three-dimensional structure.Fluorescence properties of compounds 8-11 were studied,showing the characteristic emission peaks of lanthanide ions,respectively.