Synthesis, Structures And Properties Of Complexes Of 4,4′-bipyridine And Pyrazine-2,3,5,6-tetracarboxylic Acid

4,4′-bipyridine has two coordination sites and it's a good bridging ligands with non-branched-chain and small steric hindrance. The two pyridine rings around the carbon-carbon bond can be any rotation, so it can form a variety of spatial structure of the complex. Pyrazine-2,3,5,6-tetracarboxylic acid has rich coordination sites and a greatly symmetrical structure with a high degree of rigidity. By using Pyrazine-2,3,5,6-tetracarboxylic acid and 4,4′- bipyridine as mixed bridging ligand, novel 1D chains, 2D framework, 3D network complexes have been successfully synthesized. Furthermore, the novel water cluster, the structure and the coordination mode of the complex are also explained in detailed.In this studies four complexes with H4pztc and 4,4′-bipyridine {[Cu3(pztc)2(Hbpy)2(bpy)(H2O)6]·6.5H2O}n(1), {[Zn3(pztc)2(Hbpy)2(bpy)(H2O)4]·7H2O}n(2), {Ag4(bpy)4(pztc)}n (3), {Ag2(bpy)1.5(pztc)0.5}n(4) (H4pztc = Pyrazine-2,3,5,6-tetracarboxylic acid, bpy = 4,4′- bipyridine) have been synthesized and characterized by thermogravimetric (TG) analysis, IR spectrum, Fluorescence spectrum, UV absorption spectrum, and single-crystal X-ray diffraction.Complex 1 is a 1D chain structure like a fish bone, crystallized in the Orthorhombic space group Pnna. Complexes 2 is a 3D network structure crystallized in the Orthorhombic space group Pcca. Metal ions are all six-coordinated in the Complex 1 and Complex 2, exhibiting distorted octahedral coordination geometry. Through the normal coordination bonds Complex 2 form the 3D network structure. Complex 3 crystallizes in the Orthorhombic space group Ibca and forms the 2D layered structure. Complex 4 crystallizes in the Triclinic space group P1 which forms 3D network structure. Silver ions in the Complex 3 and Complex 4 are all three-coordinated, exhibiting Triangle planer or T-shaped coordination geometry. Complex 4 formed the 3D network structure by the weak bonding like metal-metal and metal-oxygen bonds. The (H2O)4 water cluster and (H2O)10 water cluster are presented in 1 and 2 respectively.