Calcium coordination compounds of anionic forms of hydrogen dipicolinate and quinolinate: synthesis, characterization, crystal structures and DFT studies

Two calcium coordination compounds [Ca(2,6-Hpdc)2(H2O)2] 1 and [Ca2(2,3-pdc)2(H2O)6]n 2 (where 2,6-H2pdc = 2,6-pyridinedicarboxylic acid 2,3-H2pdc 2,3-pyridinedicarboxylic acid) were grown at room temperature. The characterized using elemental analysis, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric powder X-ray diffraction single crystal crystallographic analysis. structures of both are stabilized by a network hydrogen bonds arising from coordinated water molecules carboxylate groups. Computational analysis revealed that compound has large energy gap (9.221 eV), suggesting high excitation energies chemical hardness making it better electron acceptor while displayed smaller (5.156 which is indicative softer molecule with polarizability reactivity.