In situ synthesis of (5-phenyl-1H-pyrazole-3-carboxylic acid) metal complexes and their stable supramolecular microporous frameworks

By in situ generation of ppc ligand in the presence MCl2 and 3-phenyl-1H-pyrazole-5-carbohydrazide at room temperature, the complexes, [M(ppc)2(DMF)2]·2H2O (M = Co (1) and Ni (2); ppc = 5-phenyl-1H-pyrazole-3-carboxylic acid), were synthesized and characterized by single-crystal X-ray diffraction, IR spectrum, UV spectra and elemental analysis. X-ray structural analysis revealed that the complexes were formed into 3D supramolecular polymers via C–H⋯O and π⋯π interactions. The 3D supramolecular networks of two complexes were constructed from 1D nanochannels along the c-direction with the disorder DMF and water solvent molecules shuttling easily. TG and powder X-ray diffraction analysis showed two complexes had high stability when DMF and H2O molecules were removed. Upon DMF molecules liberated, two complexes become stable microporous solid with coordination-unsaturated [M(ppc)2] as center. The electrochemical properties were also investigated.