Porous materials are important in a wide range of applications including molecular separations and catalysis. We demonstrate that covalently bonded organic cages can assemble into crystalline microporous materials. The porosity is prefabricated and intrinsic to the molecular cage structure, as opposed to being formed by non-covalent self-assembly of non-porous sub-units. The three-dimensional connectivity between the cage windows is controlled by varying the chemical functionality such that either non-porous or permanently porous assemblies can be produced. Surface areas and gas uptakes for the latter exceed comparable molecular solids. One of the cages can be converted by recrystallization to produce either porous or non-porous polymorphs with apparent Brunauer-Emmett-Teller surface areas of 550 and 23 m2 g(-1), respectively. These results suggest design principles for responsive porous organic solids and for the modular construction of extended materials from prefabricated molecular pores.

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3There is great current interest in the use of porous materials for substrate storage and separations, catalysis, drug delivery, and sensing. [1][2][3][4][5] Understanding the host-guest interactions in these systems is vital if new generations of improved materials are to be developed. However, gaining such insight is challenging and often not feasible in large void materials due to lack of order in porous systems such as carbon, mesoporous silica and zeolites, 5 and also because the nature of these host-guest interactions is often based upon very weak and dynamic supramolecular contacts such as hydrogen-bond, π···π stacking, van der Waals, electrostatic or dipole interactions. Such supramolecular binding usually involves many hydrogen atoms and undergoes dynamic processes that are difficult to probe directly by experiment. 2,6 Recent studies on porous metal-organic frameworks (MOFs) for hydrogen storage, 7,8 carbon capture, 1 and hydrocarbon separations 9,10 have shown, in exceptional cases, location of guest molecules within the host via advanced crystallography studies, providing invaluable structural rationale for their function and properties. Most of these successes have been achieved within host systems that display strong confinement effects on the guest molecules and/or have specific relatively strong binding sites such as open metal centers. 7-12 However, host-guest systems involving primarily soft supramolecular interactions usually lead to serious positional disorder of the guest molecules, and hydrogen atoms involved in these binding processes are not readily seen or defined from crystallography studies, 13,14 leading to problems in defining the dynamics and motions of such host-guest systems.As a result, information on molecular binding dynamics and the motion of guests within the confined space of MOF hosts is largely lacking. Herein, we report the application of combined inelastic, quasi-elastic and elastic neutron scattering and synchrotron X-ray diffraction coupled to density functional theory (DFT) calculations to directly visualise the dynamics of host-guest interactions between adsorbed C 2 -hydrocarbons and the hydroxylfunctionalised porous MOF NOTT-300, which exhibits high selectivity and uptake capacity for unsaturated hydrocarbons. Moreover, direct observation of the mobility and diffusion for these adsorbed hydrocarbons within NOTT-300 has been achieved, representing important methodologies for their potential kinetic separations. These complementary experiments using dynamic, kinetic and static approaches lead to the same conclusion: four types of soft supramolecular interactions cooperatively bind guest molecules in these functionalised cavities, and these finetuned interactions lead to optimal uptake kinetics and binding dynamics affording excellent selectivities between these hydrocarbons. Results and discussionMaterial and characterisation. and 5, respectively. These selectivities are, however, subject to uncertainties associated with isotherm measurement of the extremely low ...

Understanding the mechanism by which porous solids trap harmful gases such as CO(2) and SO(2) is essential for the design of new materials for their selective removal. Materials functionalized with amine groups dominate this field, largely because of their potential to form carbamates through H(2)N(δ(-))···C(δ(+))O(2) interactions, thereby trapping CO(2) covalently. However, the use of these materials is energy-intensive, with significant environmental impact. Here, we report a non-amine-containing porous solid (NOTT-300) in which hydroxyl groups within pores bind CO(2) and SO(2) selectively. In situ powder X-ray diffraction and inelastic neutron scattering studies, combined with modelling, reveal that hydroxyl groups bind CO(2) and SO(2) through the formation of O=C(S)=O(δ(-))···H(δ(+))-O hydrogen bonds, which are reinforced by weak supramolecular interactions with C-H atoms on the aromatic rings of the framework. This offers the potential for the application of new 'easy-on/easy-off' capture systems for CO(2) and SO(2) that carry fewer economic and environmental penalties.

A software package for the calibration and processing of powder X-ray diffraction and small-angle X-ray scattering data is presented. It provides a multitude of data processing and visualization tools as well as a command-line scripting interface for on-the-fly processing and the incorporation of complex data treatment tasks. Customizable processing chains permit the execution of many data processing steps to convert a single image or a batch of raw twodimensional data into meaningful data and one-dimensional diffractograms. The processed data files contain the full data provenance of each process applied to the data. The calibration routines can run automatically even for high energies and also for large detector tilt angles. Some of the functionalities are highlighted by specific use cases.