Two Pillared Metal–organic Frameworks Comprising a Long Pillar Ligand used as fluorescent sensor for nitrobenzene and heterogeneous catalyst for Knoevenagel condensation reaction

Two new pillared zinc and cadmium-organic frameworks were synthesized by incorporating two different organic linkers, namely 2-aminoterephthalic acid as an oxygen-donor linker and N4,N4 -bis(pyridin-4-ylmethylene)-biphenyl-4,4 -diamine as a long pillaring strut. The structure of these two frameworks was analyzed using X-ray crystallography, FT-IR spectroscopy, thermogravimetric and elemental analyses. Their structural features as well as their stability were studied. These two MOFs having the same organic compositions and the same network topology but different inorganic nodes differ in their chemical stability. Also, these two frameworks respond differently to nitrobenzene when they are used as a fluorescent sensor. Furthermore, the catalytic behavior of one of these frameworks toward Knoevenagel condensation reaction was investigated.