Synthesis of secondary and tertiary amine-containing MOFs: C–N bond cleavage during MOF synthesis

Abstract

Secondary and tertiary amine-containing metal–organic frameworks (MOFs) have been synthesized, and unprecedented C–N bond cleavage phenomena were observed during MOF formation. Utilizing the secondary amine-containing ligand (BDC-NHMe), three new MOFs have been prepared, two of which are zinc(II)-based, IRMOF-NHMe (IRMOF = isoreticular MOF) and DMOF-1-NHMe (DMOF = dabco MOF), in addition to the zirconium(IV)-based UiO-66-NHMe (UiO = University of Oslo). The tertiary amine-containing ligand (BDC-NMe₂) was converted to the secondary amine-containing ligand (BDC-NHMe) under both IRMOF and UiO-66 synthesis conditions, indicating an in situ C–N bond cleavage of ligand during MOF formation. In contrast, the tertiary amine-containing DMOF-1-NMe₂ was successfully synthesized and studied for CO₂ adsorption experiments.