Rubbery organic frameworks-tuning the Gaz-diffusion through dynameric membranes

High permeability whilst keeping a reasonable selectivity is the most important challenge in developing membrane systems for gas separation. Valuable performances are usually obtained with polymeric membranes for which the gas transport is controlled by the gas-diffusivity in glassy polymers and by gas-solubility in rubbery polymers. During the last decade, important advances in this field are related to the molecular control of the gas separation properties. The combination/replacement of classical glassy polymers with metal-organic crystalline frameworks (MOFs, ZIFs, zeolites…) providing reasonable permeability through porous free volume network and high selectivity due to so-called “selectivity centers” specifically interacting with the gas molecules. Despite the impressive progress, important difficulties are observed to get dense mechanically stable thin layer MOFs on various supports. Taking advantage of high permeabilities observed with the rubbery polymers and to their flexible casting properties, there should be very interesting to build rubbery organic frameworks-ROFs, as alternative for gas membrane separation systems. Here we use low macromolecular constituents and dialdehyde core connectors in order to constitutionally generate rubbery organic. Differently to rubbery polymeric membranes the ROFs performances depend univocally of diffusional behaviors of gas molecules through the network. For all gases, a precise molecular composition of linear and star-type macromonomers generates an optimal free volume for a maximal diffusion through the matrix. These results should initiate new interdisciplinary discussions about highly competitive systems for gas separation, constitutionally controlled at the molecular scale. Please click Additional Files below to see the full abstract

Salt-excluding artificial water channels exhibiting enhanced dipolar water and proton translocation

Aquaporins (AQPs) are biological water channels known for fast water transport (~108-109 molecules/s/channel) with ion exclusion. Few synthetic channels have been designed to mimic this high water permeability, and none reject ions at a significant level. Selective water translocation has previously been shown to depend on water-wires spanning the AQP pore that reverse their orientation, combined with correlated channel motions. No quantitative correlation between the dipolar orientation of the water-wires and their effects on water and proton translocation has been reported. Here, we use complementary X-ray structural data, bilayer transport experiments and molecular dynamics (MD) simulations to gain key insights and quantify transport. We report artificial imidazole-quartet water channels with 2.6-Å pores, similar to AQP channels, that encapsulate oriented dipolar water-wires in a confined chiral conduit. These channels are able to transport ~106 water molecules per second, which is within two orders of magnitude of AQPs’ rates, and reject all ions except protons. The proton conductance is high (~5 H+/s/channel) and approximately half that of the M2 proton channel at neutral pH. Chirality is a key feature influencing channel efficiency. Please click Additional Files below to see the full abstract

THE RELATION BETWEEN TERRITORIAL COLECTIVITIES IN FRANCE AND THE EUROPEAN UNION. THOUGHTS ON THE CROSS-BORDER COOPERATION

France, one of the founding members of the European Union, is a unitary state from the administrativeterritorial point of view, based on deep centralism. Having territorial collectivities with highly complex structure (communes, departments, regions, sui-generis collectivities and overseas collectivities), France committed itself to cooperation not only between its own administrative structures, but also to cross-border cooperation within the European Union. After showing reluctance to external actions underwent by territorial collectivities, France ended up with acknowledging this right of its territorial collectivities within the «decentralized cooperation», expressly brought under regulation by the Law of 6 February 1992. According to the law, there is no need for any ratification on behalf of the State to allow cooperation between territorial collectivities, within the boundaries of their competence. The Law of 1992 thus authorized the territorial collectivities to close agreements with other collectivities from abroad. Furthermore, the Law of 4 February 1995 allowed several treaties with the border states to be signed, thus creating the SAAR-LOR-LUX region (an European cross-border region that made way for cooperation between Germany, France and Luxembourg). The French legislation also allowed several European districts to be created, acting as local groups for cross-border cooperation, created on the initiative of territorial collectivities. The aim of our study is to identify the main relationship between territorial collectivities in France and EU and to analyze the cooperation instruments used by the French collectivities in order to foster the cross-border cooperation

1,3,4-Thiadiazole Derivatives. Part 91. Synthesis and Biological Activity of Metal Complexes of 5-(2-Aminoethyl)-2-Amino-1,3,4-Thiadiazole

Metal complexes of the title ligand (L) containing Co(II), Ni(II) and Cu(II) were prepared and characterized by elemental analysis, IR, electronic spectroscopy and conductimetry. The new derivatives, possessing the following formulae, CuL2(OH)2, NiL2Cl2, and [Co2LCl4]n showed in vitro antifungal activity against Aspergillus and Candida spp

1,4-Bis(2-pyridylmethyl­eneamino­meth­yl)benzene

The asymmetric unit of the centrosymmetric title compound, C20H18N4, contains one half-mol­ecule. The pyridine and benzene rings are oriented at a dihedral angle of 77.21 (7)°

Bis[μ-1-hexyl-3-(2,3,5,6,8,9,11,12-octa­hydro-1,4,7,10,13-benzopenta­oxacyclo­penta­decin-15-yl)urea]bis­(azido­sodium) chloro­form disolvate

In the title compound, [Na2(N3)2(C21H34N2O6)2]·2CHCl3, the sodium cation is hepta­coordinated by five O atoms of the crown ether unit of the 1-hexyl-3-(2,3,5,6,8,9,11,12-octa­hydro-1,4,7,10,13-benzopenta­oxacyclo­penta­decin-15-yl)urea (L) ligand, the O atom of the urea group of the second, symmetry-related L ligand, and one N atom of the azide anion. The experimentally determined distance 2.472 (2) Å between the terminal azide N atom and the sodium cation is substanti­ally longer than that predicted from density functional theory (DFT) calculations (2.263 Å). The crown ethers complexing the sodium cation are related by an inversion centre and form dimers. The urea groups of the two L ligands are connected in a head-to-tail fashion by classical N—H⋯N hydrogen-bonding inter­actions and form a ribbon-like structure parallel to the b axis. Parallel ribbons are weakly linked through C—H⋯N, C—H⋯O and C—H⋯π inter­actions

Tunable membranes incorporating artificial water channels for high-performance brackish/low-salinity water reverse osmosis desalination

Membrane-based technologies have a tremendous role in water purification and desalination. Inspired by biological proteins, artificial water channels (AWCs) have been proposed to overcome the permeability/selectivity trade-off of desalination processes. Promising strategies exploiting the AWC with angstrom-scale selectivity have revealed their impressive performances when embedded in bilayer membranes. Herein, we demonstrate that self-assembled imidazole-quartet (I-quartet) AWCs are macroscopically incorporated within industrially relevant reverse osmosis membranes. In particular, we explore the best combination between I-quartet AWC and m-phenylenediamine (MPD) monomer to achieve a seamless incorporation of AWC in a defect-free polyamide membrane. The performance of the membranes is evaluated by crossflow filtration under real reverse osmosis conditions (15 to 20 bar of applied pressure) by filtration of brackish feed streams. The optimized bioinspired membranes achieve an unprecedented improvement, resulting in more than twice (up to 6.9 L center dot m-2 center dot h-1 center dot bar-1) water permeance of analogous commercial membranes, while maintaining excellent NaCl rejection (>99.5%). They show also excellent performance in the purification of low-salinity water under low-pressure conditions (6 bar of applied pressure) with fluxes up to 35 L center dot m-2 center dot h-1 and 97.5 to 99.3% observed rejection