We demonstrate that fluorous metal-organic frameworks (FMOFs) are highly hydrophobic porous materials with a high capacity and affinity to C(6)-C(8) hydrocarbons of oil components. FMOF-1 exhibits reversible adsorption with a high capacity for n-hexane, cyclohexane, benzene, toluene, and p-xylene, with no detectable water adsorption even at near 100% relative humidity, drastically outperforming activated carbon and zeolite porous materials. FMOF-2, obtained from annealing FMOF-1, shows enlarged cages and channels with double toluene adsorption vs FMOF-1 based on crystal structures. The results suggest great promise for FMOFs in applications such as removal of organic pollutants from oil spills or ambient humid air, hydrocarbon storage and transportation, water purification, etc. under practical working conditions.

A fluorous metal−organic framework, FMOF-1, is obtained by reaction of Ag(I) with 3,5-bis(trifluoromethyl)-1,2,4-triazolate, giving rise to a neutral, hydrogen-free, extended 3D nanotubular porous framework consisting of tetranuclear clusters [Ag4Tz6] connected by three-coordinate Ag(I) centers. The fluoro-lined channels and cavities of the framework show hysteretic adsorption of H2 with a volumetric capacity of 41 kg/m3 at 77 K and 64 bar. The framework also exhibits very high adsorptions for O2 and N2 with volumetric uptake of ∼550 and 400 kg/m3 at 77 K even at very low pressures (<10-2 bar).

The kinetics of methane hydrate formation was investigated by in-situ time-of-flight neutron powder diffraction. Samples were prepared from deuterated ice particles (< 0.25 mm) and transformed to clathrate hydrate by pressurizing the system with methane gas. The rates of sI methane hydrate formation were measured in-situ under isothermal conditions with a methane pressure of 1000 psi (6.9 MPa). Kinetic data were analyzed in terms of a shrinking core model, including possible contributions of nucleation, methane diffusion, and interface reaction. The data support the hypothesis that methane hydrate formation reaction from ice particles is diffusioncontrolled. The reaction starts quickly at the nucleation stage, which propagates to form a hydrate layer that covers the ice particle. Further reaction is limited by the growth of the hydrate layer and inward diffusion of methane molecules through the hydrate layer to the unreacted ice core. The reaction rate at the interface between hydrate and unreacted ice particle is fast compared to that of methane diffusion. The conversion of ice particle to methane hydrate follows Arrhenius behavior, from which an activation energy of 14.7(5) kcal/ mol was derived. Complete transformation of ice to methane hydrate was achieved through temperature rampingsa nonisothermal procedure that involves slowly increasing the sample temperature through the ice melting point.

Playing accordion: Cooling a single crystal of a microporous fluorous metal-organic framework under ambient atmosphere leads to very large breathing upon gas adsorption, during which multiple N(2) molecules are filled into channels and cages (see picture). While the framework exhibits remarkable positive thermal expansion under vacuum, a gigantic apparent negative thermal expansion takes place when the crystal is exposed to N(2) at ambient pressure.