Abstract
We report the modulation of reactivity of nitrogen dioxide (NO(2) ) in a charged metal-organic framework (MOF) material, MFM-305-CH(3) in which unbound N-centres are methylated and the cationic charge counter-balanced by Cl(-) ions in the pores. Uptake of NO(2) into MFM-305-CH(3) leads to reaction between NO(2) and Cl(-) to give nitrosyl chloride (NOCl) and NO(3) (-) anions. A high dynamic uptake of 6.58 mmol g(-1) at 298 K is observed for MFM-305-CH(3) as measured using a flow of 500 ppm NO(2) 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 NO(2) molecules within MFM-305-CH(3) 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.