Introduction of a urea R-NH-CO-NH-R group as a seven-membered diazepine ring at the center of 4,4'-biphenyl-dicarboxylic acid leads to a urea-functionalized dicarboxylate linker (L1) from which four zinc metal-organic frameworks (MOFs) could be obtained, having a {Zn(μ-O)(OC-)} SBU and IRMOF-9 topology (compound [Zn(μ-O)(L1)], 1, from dimethylformamide, DMF) or a {Zn(OC-)} paddle-wheel SBU in a 2D-network (compound [Zn(L1)(DEF)·2.5DEF], 2, from diethylformamide, DEF). Pillaring of the 2D-network of 2 with 4,4'-bipyridine (bipy) or 1,2-bis(4-pyridyl)ethane (bpe) gives 3D frameworks with rhombohedrally distorted pcu-a topologies ([Zn(L1)(bipy)], 3 and [Zn(L1)(bpe)], 4, respectively). The 3D-frameworks 1, 3, and 4 are 2-fold interpenetrated with ∼50% solvent-accessible volume, albeit of apparently dynamic porous character, such that N adsorption at 77 K does not occur, while H at 77 K (up to ∼1 wt %) and CO at 293 K (∼5 wt %) are adsorbed with large hystereses in these flexible MOFs. The urea-functionalized MOF 3 exhibits an uptake of 10.9 mmol g (41 wt %) of SO at 293 K, 1 bar, which appears to be the highest value observed so far. Compounds 3 and 4 adsorb 14.3 mmol g (20 wt %) and 17.8 mmol g (23 wt %) NH, respectively, which is at the top of the reported values. These high uptake values are traced to the urea functionality and its hydrogen-bonding interactions to the adsorbents. The gas uptake capacities follow the specific porosity of the frameworks, in combination with pore aperture size and affinity constants from fits of the adsorption isotherms.

ZIF-318, isostructural to ZIF-8 but built from the mixed linkers of 2-methylimidazole and 2-trifluoromethylimidazole can be activated for gases sorption and the separation of ethane/ethene mixtures.

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In gas insulated substations, the main trend is to move from SF6 to more environmentally friendly alternatives. The main SF6 alternatives are mixtures based on CO2, with additives of O2 and the fluorinated gases C4F7N or C5F10O. Mixtures with fluorinated additives of up to 10 % were investigated in a test setup with a free burning arc. Gas composition was measured for each gas after mixing, and in-between some arcing sequences. Gas mixtures were investigated by three mobile gas analyzers and by three laboratories. The results showed that for clean gas mixtures, all methods showed comparable results. Determination of the heavily arced gas mixture decomposition is challenging and requires detailed laboratory analysis. A range of decomposition rates were shown for both C4F7N and C5F10O. In addition, the influence of the gas used for arcing on the arcing contacts made of Cu/W (20/80wt%) was investigated. A higher mass loss on the anode than on the cathode was found for all contacts. There is an indication of a higher erosion rate for arcing contacts used in SF6 alternatives than for those used with SF6, but further investigation is required. No major differences were found during visual inspection of the pins.