Syntheses, Structures And Properties Of Transition And Lanthanide Metal Complexes Based On Pyridinecarboxylate Derivatives

Coordination polymers, refer to compounds that are self-assembled by metal ions and organic ligands, are of increasing interest in coordination chemistry not only because of their intriguing structural topologies but also of their potential application in luminescence, catalysis, magnetism, molecule recognition, gas absorption and so on. It is well known that the properties of coordination polymers are heavily influenced by their structures. Therefore, to investigate the rule and factors influencing self-assembly of functional complexes is of initial emphasis in the field of crystal engineering. However, it is still a great challenge to make synthesis of the coordination polymers with desirable structures and functions under control, becaure the preparing processes of the metal-organic coordination complexes are influenced by many factors.Since transition metal ions Cd2+and lanthanide metal ions Eu3+, Sm3+exhibit good optical properties, and transition metal ions Co2+, Ni2+and Mn2+are paramagnetic, the Coordination polymers constructed with these metal ions may have promising optical and magnetic properties. Based on these viewpoints, we choosed these ions as metal coordination center nodes, and make3-(3,5-dicarboxyl phenyly)-4-carboxyl pyridine,5-(pyridine-2-ylmethoxy)isophthalic acid5-(pyridine-3-ylmethoxy) Isophthalic acid,5-(pyridine-4-ylmethoxy)-isophthalic acid as organic linker, accompanied by1,10-Phenanthroline,2,2’-Dipyridyl and4,4’-Dipyridyl ligands, and obtained the following ten novel coordination polymers under hydrothermal conditions.{[Mn3(OH)(HL)(L)(4,4’-bpy)(H2O)2]2·2(4,4’-bpy)4H2O}n(1){[Cu2(OH)(L)(2,2’-bpy)2]·5H2O}n(2){[Cd(Lo)]2·H2O}n(3){[Ni2Lp(4,4’-bpy)2][NiLP(4,4’-bpy)(H2O)]}n (4)[Co2(Lm)2(4,4’-bpy)]n(5){[Co(Lm)(2,2’-bpy)]·H2O}n(6)[Co(Lm)(1,10-phen)]n(7) [Mn2(Lm)2(4,4’-bpy)]n(8){[Ln2(Lm)3(H2O)4]·(4,4’-bpy)·3H2O}n(Ln=Sm(9),Eu(10))All of the complexes were characterized by single crystal X-ray diffraction, X-ray powder diffraction, IR spectra and elemental analysis. The corresponding luminescence and thermogravimetric analysis were also investigated. Complexes1,5and8feature three-dimensional networks, while complexes3、4、6、9and10exhibit two-dimensional layer-structures, and complexes2and7are one-dimensional belts. It should be pointed out that two different kinds of layers are included in compound4simultaneously.