Amorphous zirconium metal-organic frameworks assembled from mixed porphyrins as solvent-free catalysts for Knoevenagel condensation.

Three mixed porphyrins, icpp (1-3), were synthesized the reactions of 4-formylbenzoic acid and 4-imidazolecarboxaldehyde, and then five amorphous or crystalline Zr-MOFs-SPUZ (1-5) were obtained from icpp (1-3), timp and tcpp, respectively. The catalytic activities of the synthesized porphyrins and MOFs were studied on the Knoevenagel condensation of aldehydes and malononitrile under solvent-free conditions. Among them, amorphous MOF SPUZ-1 showed the highest catalytic activity.