Transfer approximately 10 milligrams of the MOF solid exchanged with UiO-66-Triazole to a powder X-ray diffraction sample holder. Place the sample holder in the diffractometer, and collect the powder X-ray diffraction pattern. To begin NMR characterization, transfer around 30 milligrams of the exchanged MOF solid to a fresh four milliliter vial.
Then move 400 microliters of DMSO-d6 to the MOF sample using a micro pipette. Transfer 200 microliters of 4.14 molar ammonium fluoride deuterium oxide solution to a DMSO-d6 suspension of MOF powder using a micro pipette. Sonicate the heterogeneous mixture for 30 minutes until the MOF is dissolved in the dimethyl sulfoxide deuterium oxide mixed solvent after digestion.
Once done, remove any remaining insoluble solids by filtering the solution through a polyvinylidene difluoride syringe filter while transferring it from the four milliliter vial to a nuclear magnetic resonance tube. To determine the success of the exchange, powder X-ray diffraction patterns were measured and compared to pristine UiO-66 MOF for crystallinity. The position of reflection peaks, relative intensity, and broadness in the powder X-ray diffraction patterns of exchanged UiO-66-Triazole and UiO-66-Tetrazole matched with pristine UiO-66 MOFs, indicating that the ligand exchange did not impact the framework structure.
The exchange ratios were determined by comparing the integration of nonfunctionalized BDC and BDC-Triazole or BDC-Tetrazole. The exchange ratios for Triazole and Tetrazole were found to be 33%and 30%respectively from post synthetic ligand exchange analysis.
