Thermal stabilities and crystal structures of two supramolecular microporous frameworks based on carboxylate-dipyridyl mix-ligands

The mix-ligand system of 5-(4-carboxy-2-nitrophenoxy)isophthalic acid (HСn-H₂Ipa) and dipyridyl-type molecule produces two M(II) porous coordination polymers, namely {Zn(HCn-Ipa)(Dpe)(H₂O)] · 2H₂O} _n (I) and {Co(Cn-HIpa)(Dpe)(H₂O)₃] · 2.5H₂O} _n (II) (Dpe = 1,2-di(4-pyridyl) ethylene). Structure determinations reveal that two complexes feature different one-dimensional (1D) polymers assembling into supramolecular microporous frameworks with different thermal stabilities. The 3D supramolecular frameworks of complex I show relatively lower stability, which can be caused by relatively larger porous cavity absent of the strong hydrogen bonds interaction, whereas thick-layer blocks in complex II are cohered further together by H-bonding interactions to form its 3D supramolecular network with relatively higher stability, indicating extraordinarily stable H-bonding systems; CIF files CCDC nos. 966919 (I) and 966920 (II).