Metal-carbamate complexes as precursors for the synthesis of metal-organic frameworks (MOFs)

Metal-carbamate complexes of Cu (II), Zr (IV) were synthesized and characterized by IR and NMR spectroscopy. These complexes were then used as precursors for the synthesis of metal-organic frameworks (MOFs), in particular HKUST-1 and UiO-66, in combination with carboxylic ligands such as terephthalic acid and trimesic acid. The syntheses were conducted in aprotic dipolar solvents, varying parameters such as reagent concentration, solvents, addition method, linker protonation state, temperature and reaction time. The resulting MOFs were characterized by X-ray powder diffractometry, NMR spectroscopy, scanning electron microscopy, thermogravimetric analysis and nitrogen adsorption measurements at 77 K. The results obtained suggest that metal-carbamato complexes are suitable precursors for the synthesis of MOFs. The high reactivity of these complexes allows to perform syntheses at room temperature that afford products in high yields and comparable quality to those obtained with literature procedures and from classical precursors.