Pressures up to 0.8 GPa have been used to squeeze a range of sterically 'oversized' C5-C8 alkane guest molecules into the cavities of a small-pore Sc-based metal-organic framework. Guest inclusion causes a pronounced reorientation of the aromatic rings of one third of the terephthalate linkers, which act as 'torsion springs', resulting in a fully reversible change in the local pore structure. The study demonstrates how pressure-induced guest uptake can be used to investigate framework flexibility relevant to 'breathing' behavior and to understand the uptake of guest molecules in MOFs relevant to hydrocarbon separation.

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We propose a simple method to predict solubility in mixed solvents, combining experimental data for solubility in pure solvents with non-ideal contributions obtained from molecular simulation. By evoking a well-established thermodynamic model for mixed solvent, we provide rationale and justification for this hybrid approach. We test the accuracy of the method for solubility prediction in two highly non-ideal mixtures, CO 2 in ethanol + water, and CH 4 in MDEA + water. Non-ideal behaviour in each system is characterised using molecular simulation across the full range of compositions and for temperatures covering the range 273.15 K-373.15 K. Comparison against experimental Henry's law constants for CO 2 and CH 4 gives mean absolute errors of 6.9% and 27%, respectively. We investigate the origin of non-ideal Henry's law behaviour in each of the mixed solvents by interrogating radial distribution functions from molecular simulation, finding increased association of CO 2 and CH 4 with the organic solvents at elevated temperatures.

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