A nanotubular metal-organic framework (MOF), {[(WS(4)Cu(4))I(2)(dptz)(3)]·DMF}(n) (dptz = 3,6-di(pyridin-4-yl)-1,2,4,5-tetrazine, DMF = N,N-dimethylformamide) for sensing small solvent molecules is presented. When accommodating different solvent molecules as guests, the resulting inclusion compounds exhibit different colors depending on the solvent guests, and more interestingly, the band gaps of these solvent-included complexes are in linear correlation with the polarity of the guest solvents. The solvent molecules can be sensed by the changes of UV-vis spectra of the corresponding inclusion compounds, showing a new way of signal transduction as a new kind of sensor. The sensing by such a MOF occurs within the channel-containing material rather than on the external surface.

We report the one-pot reactions of the 16e(-) half-sandwich complex CpCoS(2)C(2)B(10)H(10) (1), methyl propiolate, and 3e(-)-donor ligands, which lead to selective B-functionalization at carborane with cyclopentadienyl as a functional group at ambient temperature in good yields. Metal-promoted activations of both a B-H bond of the carborane and a C-H bond of the Cp unit take place sequentially in the cooperation of organic ligands. The reaction requires a 3e(-)-donor ligand and an activated alkyne and is therefore suitable for a broad range of substrates. This investigation provides a simple and efficient synthetic route to B-functionalized carborane derivatives.

NH3 (ammonia) is a promising energy resource owing to its high hydrogen density. However, its widespread application is restricted by the lack of efficient and corrosion-resistant storage materials. Here, we report high NH3 adsorption in a series of robust metal-organic framework (MOF) materials, MFM-300(M) (M = Fe, V, Cr, In). MFM-300(M) (M = Fe, V III , Cr) show fully reversible capacity for >20 cycles, reaching capacities of 16.1, 15.6 and 14.0 mmol g -1 , respectively, at 273 K and 1 bar. Under the same condition, MFM-300(V IV ) exhibits the highest uptake among this series of MOFs of 17.3 mmol g -1 . In situ neutron powder diffraction, single crystal X-ray diffraction and electron paramagnetic resonance spectroscopy confirm that the redox-active V centre enables host-guest charge-transfer, with V IV being reduced to V III and NH3 oxidised to hydrazine, N2H4. A combination of in situ inelastic neutron scattering and DFT modelling has revealed the binding dynamics of adsorbed NH3 within these MOFs to afford a comprehensive insight into the application of MOF materials to the adsorption and conversion of NH3.

Hydrogen bonds dominate many chemical and biological processes, and chemical modification enables control and modulation of host–guest systems. Here we report a targeted modification of hydrogen bonding and its effect on guest binding in redox-active materials. MFM-300(VIII) {[VIII2(OH)2(L)], LH4=biphenyl-3,3′,5,5′-tetracarboxylic acid} can be oxidized to isostructural MFM-300(VIV), [VIV2O2(L)], in which deprotonation of the bridging hydroxyl groups occurs. MFM-300(VIII) shows the second highest CO2 uptake capacity in metal-organic framework materials at 298 K and 1 bar (6.0 mmol g−1) and involves hydrogen bonding between the OH group of the host and the O-donor of CO2, which binds in an end-on manner, =1.863(1) Å. In contrast, CO2-loaded MFM-300(VIV) shows CO2 bound side-on to the oxy group and sandwiched between two phenyl groups involving a unique ···c.g.phenyl interaction [3.069(2), 3.146(3) Å]. The macroscopic packing of CO2 in the pores is directly influenced by these primary binding sites.

Porous MFM-202a (MFM = Manchester Framework Material, replacing the NOTT designation) shows an exceptionally high uptake of acetylene, 18.3 mmol g −1 (47.6 wt %) at 195 K and 1.0 bar, representing the highest value reported to date for a framework material. However, at 293 K and 10 bar C 2 H 6 uptake (9.13 mmol g −1 ) is preferred. Dual-site Langmuir-Freundlich (DSLF)-and Numerical Integration (NI)-based IAST methods have been used to analyze selectivities for C 1 to C 3 hydrocarbons. MFM-202a exhibits broadly hysteretic desorption of acetylene; such behavior is important for practical gas storage since it allows the gas to be adsorbed at high pressure but stored at relatively low pressure. Stepwise uptake and hysteretic release were also observed for adsorption of other unsaturated light hydrocarbons (ethane and propene) in MFM-202a but not for saturated hydrocarbons (methane, ethane, and propane). MFM-202a has been studied by in situ synchrotron X-ray powder diffraction to reveal the possible phase transition of the framework host as a function of gas loading. A comprehensive analysis for the selectivities between these light hydrocarbons has been conducted using both IAST calculation and dual-component mixed-gas adsorption experiments, and excellent agreement between theory and experiment was achieved.

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We report the reversible adsorption of ammonia (NH 3 ) up to 9.9 mmol g –1 in a robust Al-based metal–organic framework, MFM-303(Al), which is functionalized with free carboxylic acid and hydroxyl groups. The unique pore environment decorated with these acidic sites results in an exceptional packing density of NH 3 at 293 K (0.801 g cm –3 ) comparable to that of solid NH 3 at 193 K (0.817 g cm –3 ). In situ synchrotron X-ray diffraction and inelastic neutron scattering reveal the critical role of free −COOH and −OH groups in immobilizing NH 3 molecules. Breakthrough experiments confirm the excellent performance of MFM-303(Al) for the capture of NH 3 at low concentrations under both dry and wet conditions.

Binding of C2H2 in MFM-300(VIII) showing interactions to O–H, carboxylate O-centres and intermolecular packing.