Experimental measurements and molecular simulations were conducted for two zeolitic imidazolate frameworks, ZIF-8 and ZIF-76. The transferability of the force field was tested by comparing molecular simulation results of gas adsorption with experimental data available in the literature for other ZIF materials (ZIF-69). Owing to the good agreement observed between simulation and experimental data, the simulation results can be used to identify preferential adsorption sites, which are located close to the organic linkers. Topological mapping of the potential-energy surfaces makes it possible to relate the preferential adsorption sites, Henry constant, and isosteric heats of adsorption at zero coverage to the nature of the host-guest interactions and the chemical nature of the organic linker. The role played by the topology of the solid and the organic linkers, instead of the metal sites, upon gas adsorption on zeolite-like metal-organic frameworks is discussed.

The objective of this work was to study the adsorption and separation of the most important families of hydrocarbon compounds on metal-organic frameworks (MOFs), in comparison with zeolites. For this purpose, we have selected four probe molecules, each of them representing one of these families, i.e., o- and p-xylene as aromatics, 1-octene as an alkene, and n-octane as an alkane. The separation of these four molecules was studied by binary breakthrough experiments. To represent the large diversity of MOF structures, the experiments were carried out with (i) two MOFs with coordinatively unsaturated metal sites (CUS), i.e., Cu-btc (HKUST-1) and CPO-27-Ni, (ii) a MOF with an anionic framework and extraframework cations, i.e. RHO-ZMOF, and (iii) two rather apolar zeolitic imidazolate framework (ZIF) materials with different pore sizes, i.e. ZIF-8 and ZIF-76. Zeolite NaY and zeolite β were used as polar and apolar reference adsorbents, respectively. The results can be briefly summarized as follows: ZIFs (not carrying any polar functional groups) behave like apolar adsorbents and exhibit very interesting and unexpected molecular sieving properties. CUS-MOFs behave like polar adsorbents but show the specificity of preferring alkenes over aromatics. This feature is rationalized thanks to DFT+D calculations. MOFs with extraframework cations behave like polar (cationic) zeolites.

This paper deals with the use of the fluoride route in the synthesis of silica-based zeolites and metallophosphates (mainly gallophosphates) microporous materials, with a special emphasis on the work of the Mulhouse's group during the last recent years. The first part of this account relates to silica-based zeolites and is divided into three sections. The first section is mainly devoted to pure silica and variously substituted MFI-type zeolite (T = Al, Ga, B, Ti....), whereas the second section concerns the synthesis of pure silica or (Si, Al) zeolites with other framework topologies. Among the numerous structure-types so far obtained in fluoride medium, some of them are new and display the small F --containing double four-ring unit (D4R-F). The formation of this type of unit was first observed in the case of the clathrasil octadecasil (AST-structure-type), and is only possible due to the templating and stabilizing effect of the fluoride anion. Besides, the fluoride route leads to pure silica zeolite samples with very few or no connectivity defects. The resulting hydrophobic character allowed us to develop a new application in the field of energetics, where the systems zeolite-water can be used as molecular springs or bumpers. The third section concerns specifically the recently discovered silicogermanate zeolites with new framework topologies. Germanium acts indeed as a real structuredirecting agent, favoring in particular the formation of structures displaying the small D4R or D4R-F unit. The example of IM-10 (IM standing for Institut Français du Pétrole: Mulhouse), with UOZ structure-type, prepared in our laboratory in fluoride medium and from germanium-rich mixtures in the presence of hexamethonium cations, is described. Two other new materials called IM-9 and IM-12, both characterized by the presence of the same D4R-F or D4R unit in their structures, and prepared, respectively, from fluoride-containing or fluoride-free systems in the presence of the (6R,10S)-6,10-dimethyl-5-azoniaspiro [4,5] organic agent, are also presented. The second part concerns the phosphate-based microporous materials prepared in fluoride media and mainly the gallophosphates. As for silica-based zeolites, besides its mineralizing role, Fcan play a templating role, being found inside the small D4R units. Thus many fluorogallophosphates of the Mu-n family, with 0-D, 1-D, 2-D or 3-D frameworks (Mu standing for Mulhouse), showing such a building unit were obtained. Specific experiments are reported about the hydrothermal transformation of the fluorogallophosphate Mu-3 (1-D framework) into the fluorogallophosphate Mu-2 (3-D framework), both containing D4R-F units, and a possible mechanism of reaction is suggested. Several examples are also given where fluorine is part of the framework as terminal groups (Ga-F) or bridging species (Ga-F-Ga). Finally the observed variety