High adsorption of ammonia in a titanium-based metal-organic framework.

We report the high adsorption of NH 3 in a titanium-based metal-organic framework, MFM-300(Ti), comprising extended [TiO 6 ] ∞ chains linked by biphenyl-3,3',5,5'-tetracarboxylate ligands. At 273 K and 1 bar, MFM-300(Ti) shows an exceptional NH 3 uptake of 23.4 mmol g -1 with a record-high packing density of 0.84 g cm -3 . Dynamic breakthrough experiments confirm the excellent uptake and separation of NH 3 at low concentration (1000 ppm). The combination of in situ neutron powder diffraction and spectroscopic studies reveal strong, yet reversible binding interactions of NH 3 to the framework oxygen sites.