Synthesis and Characterization of a Cu2(pzdc)2(bix) [pzdc: 2,3-pyrazinedicarboxylate; bix: 1,3-bis(imidazol-1-yl)benzene] Porous Coordination Pillared-Layer Network

A porous coordination polymer (PCP) was prepared using pyrazine-2,3-dicarboxylate (pzdc) and the pillar ligand 1,3-bis(imidazol-1-yl)benzene) (bix) in an attempt to improve on the thermal stability and adsorption properties of Cu2(pzdc)2(L) (L = pillar ligand; typically dipyridyl-based). As-synthesized Cu2(pzdc)2(bix) showcases a highly crystalline structure (Monoclinic, P21/c, a = 11.836 A, b = 13.005 A, c = 11.389 A, β = 107.64°) that exhibits characteristic diffraction peaks also found in the dipyridyl-based PCP counterparts. Thermal analysis based on results from thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and in situ high temperature X-ray diffraction (XRD) suggests both framework contraction and expansion during the elimination of physisorbed and coordinated water, phase transition, and prior to the eventual destruction of the structure, which takes place at ca. 556 K. The thermal stability limit is an improvement over those displayed by other Cu2(pzdc)2(L) materials ...