Supramolecular assembly of a 2D coordination polymer bearing pyridine-N-oxide-2,5-dicarboxylic acid and copper ion: X-ray crystallography and DFT calculations

Abstract

Abstract As an extension of our interest in pyridine-N-oxide-dicarboxylic acids, we report the design and synthesis of a 2D coordination polymer {[Cu(Hpydco)2]·2H2O}n (1) based on the pyridine-N-oxide-2,5-dicarboxylic acid ligand (H2pydco). Compound 1 was characterized using infrared spectroscopy, CHN-elemental analyses, TGA and single crystal X-ray diffraction (SCXD). Structural analysis showed that this compound is a two-dimensional coordination polymer created by four-connected nodes defined by the copper ion and bridging Hpydco–ligands which created regular tetragons. In the packing, hydrogen bonds connect adjacent 2D sheets to extend the structure into a 3D architecture. Since H2pydco and pyridine-2,5-dicarboxylic acid have similar frameworks, we also highlight some areas of current interest in their coordination behavior by surveying reported structures (Cambridge Structural Database (CSD)) and have investigated the influence of the N-oxide moiety on the coordination mode(s) in the crystal lattice. Finally, DFT calculations have been used to compare H2pydco and pyridine-2,5-dicarboxylic acid ligands and their ability to interact with Cu(II).