| Affiliation: | 1. Department of Chemistry, University of Manchester, Manchester, M13 9PL UK Photon Science Institute, University of Manchester, Manchester, M13 9PL UK;2. Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester, M13 9PL UK;3. Department of Chemistry, University of Manchester, Manchester, M13 9PL UK;4. Department of Physics, University of Warwick, Coventry, CV4 7AL UK;5. Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA;6. Diamond Light Source, Harwell Science Campus, Oxfordshire, OX11 0DE UK;7. Department of Materials, University of Manchester, Manchester, M13 9PL UK |
| Abstract: | We report the modulation of reactivity of nitrogen dioxide (NO2) in a charged metal–organic framework (MOF) material, MFM-305-CH3 in which unbound N-centres are methylated and the cationic charge counter-balanced by Cl− ions in the pores. Uptake of NO2 into MFM-305-CH3 leads to reaction between NO2 and Cl− to give nitrosyl chloride (NOCl) and NO3− anions. A high dynamic uptake of 6.58 mmol g−1 at 298 K is observed for MFM-305-CH3 as measured using a flow of 500 ppm NO2 in He. In contrast, the analogous neutral material, MFM-305, shows a much lower uptake of 2.38 mmol g−1. The binding domains and reactivity of adsorbed NO2 molecules within MFM-305-CH3 and MFM-305 have been probed using in situ synchrotron X-ray diffraction, inelastic neutron scattering and by electron paramagnetic resonance, high-field solid-state nuclear magnetic resonance and UV/Vis spectroscopies. The design of charged porous sorbents provides a new platform to control the reactivity of corrosive air pollutants. |
