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A series of mixed Al2O3-Ga2O3 oxides were prepared with different Ga2O3 content (labeled as AlGa-x; where x is the wt % of Ga2O3) by precipitation method. The oxides were then used as supports of palladium (2 wt %) catalysts (labeled as Pd/AlGa-x). Both series of samples, AlGa-x and Pd/AlGa-x were characterized by several techniques such as Raman spectroscopy, XPS, XRD, SEM, and HRTEM, and were tested in the 2-propanol dehydration reaction. The steady-state conversions displayed by the Pd/AlGa-x series was almost twice as that obtained for the AlGa-x series in all the range of tested temperatures. It was worth noting that the presence of palladium changed the yield observed for the AlGa-x series mainly at low temperatures. While at high temperatures the Lewis acidity provided by the well dispersed Pd nanoparticles increased the activity considerably and improved the propylene production. A balance between the dispersion of palladium and the surface acidity, both related to the Ga2O3 content was responsible for the observed catalytic behavior.

In the present work, a type of zirconium metal organic framework known as UiO-66 (reported by researchers from the University of Oslo, for which it is called acronym) was used to adsorb ibuprofen and release it in a medium simulating the blood pH. The bioviability and low toxicity of the UiO-66 are the characteristics by which this nanomaterial was chosen to transport a drug. This project implemented a methodology for the synthesis of UiO-66 at room temperature; it was also achieved to adapt the techniques of in vitro release of drugs reported in the literature, to the simulated release of ibuprofen using the UiO-66 framework. The aim of the in vitro simulation was to determine the efficiency with which this material transports and releases ibuprofen to the blood. Therefore, the simulation conditions considered a physiological temperature of 37 ° C and a release medium (buffer solution of phosphates) with pH similar to the blood. The results show that the release was carried out gradually during the first 24 h. In addition, regardless of the initial concentration, the amount of ibuprofen released was the same.

In this work we have evaluated the fungicide effects causing the growth inhibition of Aspergillus niger, Fusarium solani and Penicillium chrysogenum using three metal–organic framework materials (MOFs): HKUST-1 (three-dimensional structure), HKUST-1NP doped with copper oxide nanoparticles (CuO-NPs) and sterilized HKUST-1 (which generated a one-dimensional Cu(BTC)(OH)(H2O)-type structure). The materials were synthesized by stirring at room temperature under atmospheric pressure, and were compared to commercial CuO-NPs to evaluate the toxic effects using a radial growth (inhibition halo) technique. The MOFs were thoroughly dispersed in culture media, and the fungi were cultured on potato dextrose agar plates containing different concentrations of the tested materials. A thorough characterization of the studied materials was carried out through PXRD, FTIR, N2 adsorption, TGA and SEM measurements in order to determine the physicochemical properties. For A. niger, none of the tested materials inhibited its growth; it hence proved to be resistant, due to its ability to leach copper from the compounds. In the case of F. solani, concentrations between 750 to 1000 ppm caused 100% inhibition of growth. For P. chrysogenum, it was observed that increasing the concentration of MOFs up to 1000 ppm caused a concomitant increase in inhibition. This work represents the first report underlining the possible use of MOFs as fungicides, and the results have shown growth inhibition capability in some species, opening up possible new applications in this field.

The highly porous metal–organic framework based on copper-benzenetricarboxylate (HKUST-1, Cu3(BTC)2, MOF-199) is used for a loading study of basic fuchsin (BF, neutral charge, ϕ = 12.40 A molecular diameter, 50 ppm solution), crystal violet (CV, cationic charge, ϕ = 15.10 A, 50 ppm solution) and Eriochrome Black T (EBT, anionic charge, ϕ = 15.50 A, 80 ppm solution), as chosen molecular probes for physicochemical analysis and interactions. Characterization is carried out using XRD, FTIR, SEM, and TGA, and UV-Vis is used to determine the differential concentration of loaded dye in the MOF. The adsorption process is evaluated by three incorporation methodologies: post-synthesis (PS) and one-pot in organic (OPO) or metallic (OPM) solution. XRD cell parameters reveal the general compactness of the net through ionic (CV and EBT), dipolar (BF, CV and EBT) and van der Waals (BF, CV and EBT) dye–MOF interactions. Enhanced compactness is observed for CV due to its cationic nature and medium size; the effect is not as strong in EBT, which is anionic in nature but bigger in size, and the least compactness is observed for BF, which lacks ionic interaction with the net. The samples have crystal sizes between 34 and 57 nm, which indicate the generation of nanomaterials. The employed procedures yield crystallite size in the following order: PS < OPO < OPM. The (%) adsorption of all the dyes is above 86.93%, which is observed for the EBT-PS sample as the lowest and 99.42% for BF-PS as the highest, which evidences the high displacement of equilibrium in the studied systems to the Cu3(BTC)2·dye occluded state. Thus, MOFs can be suggested as potential adsorbents/loaders of BF/CV/EBT dyes for composite material generation as well as MOF·molecule interaction studies because of their high loading ability and obtained stability as well as facile synthesis.

In the present work luminescent metal–organic frameworks consisting of terbium ions as the metallic center and 1,4 benzene-dicarboxylic acid (BDC), benzene-tricarboxylic (BTC) acid and 1,3 thiophane-dicarboxylic acid (TDC), as the organic ligands, are synthesized by the microwave assisted solvothermal method at a relatively short time. The samples are studied before and after a thermal annealing process at 400°C. The structural and chemical analysis indicate the formation of nanocrystals of about 8.8 nm, 5.0 nm and 127 nm for BDC, BTC and TDC samples, respectively. All the samples show carbon and oxygen in excess attributed probably to remnants of the N,N-Dimetilformamide used as solvent during the synthesis or to diffused particles from the atmosphere. The luminescent analysis shows a high quantum yield value for the BDC framework, 99.6%, after the annealing process, attributed to an antenna effect; whereas both the BTC and TDC samples show a higher quantum yield before annealing; 64.1% and 13.3%, respectively. The luminescence decay time is also computed in the samples resulting between 1 and 1.5 ms for both BDC and BTC samples, whereas for the TDC sample the decay time was about 0.2 ms. A noticeable daylight visible PL emission is observed in all samples.

The metal-organic framework (MOF) HKUST-1 was employed as an interaction matrix for fundamental loading studies of anthraquinone dyes. Chosen dyes were alizarin (A), alizarin S (AS), disperse blue 1 (B1), disperse blue 3 (B3), disperse blue 56 (B56) and purpurin (P). All materials were characterized by XRD, FTIR, TGA and SEM. Hence the interaction of dyes with the framework was characterized by theoretical-experimental differential analysis. One-pot loading strategy resulted in more efficient scavenging of dyes, and reached 100 % for B56 using 50 mg L-1 . SEM revealed important microstructural changes, the smaller crystals ranged 0.8-3 μm in size and almost all composite sizes were from this to higher values, reaching 70 μm, with varying shapes. Two composites were larger in size range (about 2500-1000 μm), and were shaped as rods, octahedrons and coffin lids. Indeed, the microstructure could be modulated depending on preparation conditions and type of loaded dye. For the higher loading series, N2 adsorption and XPS experiments were carried on to further evidence dye-MOF interactions. Ab initio prediction of structural properties for A@HKUST-1 and P@HKUST-1 were obtained by means of solid-state CRYSTAL14 code at the PBE0 level of theory. Computed findings evidenced two O→Cu coordinative bonds, one from O-ketone and the other from O-phenolate moiety as main interactions towards CuNET centers.

This investigation is based on a combination of experimental tools completed by a computational approach to deeply characterize the unusual adsorption behavior of the flexible MIL-53(Fe) in the presence of short linear alkanes. In contrast to the aluminum or chromium analogues we previously reported, the iron MIL-53 solid, which initially exhibits a closed structure in the dry state, shows more complex adsorption isotherms with multisteps occurring at pressures that depend on the nature of the alkane. This behavior has been attributed to the existence of four discrete pore openings during the whole adsorption process. Molecular simulations coupled with in situ X-ray powder diffraction were able to uncover these various structural states.

The adsorption of C1 to C4 linear hydrocarbons in the flexible metal organic framework MIL-53(Cr) has been followed by adsorption manometry coupled with microcalorimetry and Synchrotron X-ray powder diffraction. This experimental investigation was completed by molecular modeling. In the case of methane, the solid remains rigid whatever the adsorbate amount. However for the C2-C4 series, an increasing flexibility of the structure is observed, which is ascribed first to a breathing of the material from a large pore to a narrow pore form followed by a further expansion at high pressure. The collected thermodynamic and structural information suggests that a minimum adsorption enthalpy of ca. 20 kJ mol (-1) in the initial large pore structure of MIL-53(Cr) is required to induce the structural transition "large to narrow pore". Further, the enthalpy of adsorption can be used to predict the pressure at which the structure reopens. Finally, the magnitude of the breathing can be related to the size of the probe molecule via the van der Waals volume. The above trends have been successfully verified in the case of water and carbon dioxide. This combined experimental and theoretical approach gives the first elements for the prediction of whether or not the MIL53 and similar flexible structures will respond to gas loading and what would be the pressure required and further the amplitude of the induced breathing.

International audience; A comparison of the adsorption of water, methanol, and ethanol polar vapors by the flexible porous chromium(III) terephthalate MIL-53(Cr) was investigated by complementary techniques including adsorption gravimetry, ex situ X-ray powder diffraction, microcalorimetry, thermal analysis, IR spectroscopy, and molecular modeling. The breathing steps observed during adsorption strongly depend on the nature of the vapor. With water, a significant contraction of the framework is observed. For the alcohols, the initial contraction is followed by an expansion of the framework. A combination of IA analysis, X-ray diffraction, and computer modeling leads to the molecular localization of the guest molecules and to the identification of the specific guest-guest and host-guest interactions. The enthalpies of adsorption, measured by microcalorimetry, show that the strength of the interactions decreases from ethanol to water. Differential scanning calorimetry experiments on an EtOH/H(2)O mixture suggest a selective adsorption of ethanol over water.

A general study of the adsorption of n-alkanes in the flexible metal organic framework (MOF) MIL-53 is presented. The roles of the length of the alkyl chain (n = 1-9), the nature of the metal (Al, Cr), and temperature were investigated. The shape of the adsorption curves is driven by the alkyl chain length of the n-alkanes. While traditional type-I isotherms are observed for short alkanes (n = 1, 2), adsorbates with longer chains induce clear substeps in the isotherm curves whose positions depend on the chain length. Such substeps are due to a breathing phenomenon, as proven by ex situ X-ray diffraction analysis. They strongly depend on the amount of adsorbate in the pores and on the nature of the metal (Al, Cr), which, for a given alkane, leads to a strong change in the substep positions despite the similar characteristics of the two metals. The adsorption kinetics are highly sensitive to small variations in temperature. Their detailed analysis in different regions of the isotherms shows in some cases the existence of distinct diffusion regimes and/or conformations within the flexible phases.