Synthesis of a novel isoreticular metal–organic framework by protection and complexation of 2,5-dihydroxyterephthalic acid

A novel isoreticular metal–organic framework (IRMOF) was synthesised by controlling the coordination ability of the functional groups of a ligand. Hydroxyl groups of 2,5-dihydroxyterephthalic acid (H₂dhybdc) were protected with acetyl groups and complexation reactions of these unprotected H₂dhybdc and protected 2,5-diacetoxyterephthalic acid (H₂dacobdc) were performed with zinc ions. From the X-ray powder diffraction measurement, reaction with non-protected dhybdc results in an amorphous compound, while the compound obtained with protected dacobdc was isostructural to IRMOF-1. Hydroxyl groups of the non-protected ligand have the ability to coordinate to the metal sites and random coordination of various types of functional groups resulted in the amorphous compound, while protection of certain groups can prompt the highly ordered MOF.