A Recyclable Metal-Organic Framework as a Dual Detector and Adsorbent for Ammonia

Recyclable materials for simultaneous detection and uptake of ammonia (NH₃ ) are of great interest due to the hazardous nature of NH₃ . The structural versatility and porous nature of metal-organic frameworks (MOFs) make them ideal candidates for NH₃ capture. Herein, the synthesis of a water-stable and porous 3-dimensional Cu^II -based MOF (SION-10) displaying a ship-in-a-bottle structure is reported; the pores of the host SION-10 framework accommodate mononuclear Cu^II -complexes. SION-10 spontaneously uptakes NH₃ as a result of two concurrent mechanisms: chemisorption due to the presence of active Cu^II sites and physisorption (bulk permanent porosity). The color of the material changes from green to blue upon NH₃ capture, with the shifts of the UV/Vis absorption bands clearly seen at NH₃ concentrations as low as 300 ppm. SION-10 can be recovered upon immersion of SION-10⊃NH₃ in water and can be further reused for NH₃ capture for at least three cycles.