A layered amino-functionalized zinc-terephthalate metal organic framework: Structure, characterization and catalytic performance for Knoevenagel condensation

A new stable mixed-ligand metal organic framework Zn2(tpt)2(2-atp)I2 1 (tpt = tris (4-pyridyl) triazine, 2-atp = 2-aminoterephthalate) with split channels has been synthesized and characterized. The nitrogen containing ligands tpt and 2-atp are selected to create attractive basic sites for the catalyst. The Knoevenagel condensation between benzaldehyde and the active hydrogen compound (ethyl cyanoacetate or malononitrile) is carried out using compound 1 as solid basic catalytic support. The test results indicate that 1 is an efficient base catalyst with selective catalytic properties. It gives 37% and 99% yield respectively for the condensation products ethyl (E)-α-cyanocinnamate and 2-benzylidenemalononitrile. TG data show that the solid catalyst sample is fairly thermally stable. The compound does not show any signs of decomposition until 420 °C. PXRD data support that the catalyst remains its crystalline and framework stability after the catalysis process. These characters make it easily to be regenerated for the next cycle.