In situ hydrothermal syntheses, structures and photoluminescent properties of three coordination polymers based on 3-amidecarbonylpyrazine-2-carboxylic acid

Three coordination polymers based on 3-amidecarbonylpyrazine-2-carboxylic acid (HPyzca), [Cd(Pzdc)(H2O)]n·(H2O)n, [Pb3(Pzdc)3(H2O)]n, [Cu0.5(HPzdc)]n (H2Pzdc = 2,3-pyrazinedicarboxylic acid) have been in situ hydrothermally synthesized and characterized by single crystal X-ray diffraction analysis. The structural analysis revealed that HPyzca underwent hydrolysis to H2Pzdc under hydrothermal conditions. In compound 1, the Pzdc2− ligands link Cd(II) ions into a 2D architecture with the μ4-η1:η1:η2:η2 coordination mode. In compound 2, the ligands Pzdc2− adopt μ5-η1:η1:η2:η2:η2 and μ4-η1:η2:η2:η2 coordination modes connecting metal centers to form a new (3,4,5)-connected 6-nodal net with {42·6}{44·62}{43·62·8}{45·63·82}2{48·62} topology symbol. In compound 3, the adjacent Cu(II) centers are connected by HPzdc− to furnish polymeric chains along the [0 1 0] direction. These 1D arrays are further interlinked through Pzdc2− spacers to a 2D (4,4) coordination layer along the bc plane. Furthermore, thermal stabilities and photoluminescent properties of the compounds were also studied in the solid state.