Synthesis and characterization of Cu(II) complexes of pyrazine-2,3-dicarboxylicacid

Four copper(II) coordination polymers, {[Cu(pz(COO)2)(H2O)]4·HBr}n (1), {[Cu(pz(COO)2)(NH3)2]·H2O}n (2), {[Cu3H2(pz(COO)2)4(H2O)3]·2H2O}n (3) and {[Cu2(pz(COO)2)2(NH3)2(H2O)3][Cu(pz(COO)2)(NH3)(H2O)2][Cu(pz(COO)2)(NH3)(H2O)]·2H2O}n (4) were synthesized using pyrazine-2,3-dicarboxylic acid, CuBr2, 2-(2-aminoethylamino)ethanol/triethanol amine/ammonia in a methanol:water (1:1) solution, and the mixed ligand complexes were characterized by spectroscopic methods, thermal and elemental analysis, and magnetic susceptibility. Complexes 2 and 4 were also characterized by means of single crystal X-ray crystallography. The characterizations show that the complexes have polynuclear molecular structures, except for complex 2, and all of the complex structures form polymeric chains. Complex 4 has a pseudo-merohedral twin structure.

Four copper(II) coordination polymers {[Cu(pz(COO)2)(H2O)]4·HBr}n (1), {[Cu(pz(COO)2)(NH3)2]·H2O}n (2), {[Cu3H2(pz(COO)2)4(H2O)3]·2H2O}n (3) and {[Cu2(pz(COO)2)2(NH3)2(H2O)3][Cu(pz(COO)2)(NH3)(H2O)2][Cu(pz(COO)2)(NH3)(H2O)]·2H2O}n (4) were synthesized using pyrazine-2,3-dicarboxylic acid, CuBr2, 2-(2-aminoethylamino)ethanol/triethanol amine/ammonia in methanol:water (1:1) solution, and the mixed ligand complexes were characterized by spectroscopic methods, thermal and elemental analysis, magnetic susceptibility and single crystal X-ray crystallography.Figure optionsDownload as PowerPoint slideHighlights
► Mono- and polynuclear polymeric copper(II)-pyrazine-2,3-dicarboxylic acid complexes.
► Effects of fully neutralized and unneutralized ligands on the copper(II)-pyrazine-2,3-dicarboxylic acid complexes.
► Five-coordinated mononuclear and five and six coordinated polynuclear-polymeric copper(II) complexes.
► Effects of neutral ligand exchange on the coordination modes and on the crystal systems.
► Pseudo-merohedral twin formation with three linear polymeric chains of Cu(II)-pyrazine-2,3-dicarboxylic acid complexes.