Modulation of Uptake and Reactivity of Nitrogen Dioxide in Metal‐Organic Framework Materials

Abstract

AbstractWe 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.