Phosphonic acid‐containing polysulfones as anticorrosive layers

As a part of research work to elaborate polymeric materials for metal corrosion protection, we have developed a new family of phosphonic acid‐containing polymers. The synthesis and the characterization of polysulfones bearing alkyl phosphonate ester side groups are first described. These polymers are synthesized by direct polycondensation of a phosphonate ester‐containing bisphenol by aromatic nucleophilic substitution. The physicochemical properties of the resulting polymers are described. Acidic hydrolysis of phosphonate esters results in the formation of phosphonic acid groups. A series of phosphonic acid‐containing polysulfones is therefore obtained and characterized. A preliminary evaluation of the anticorrosive properties of these polymers is described. In 0.25M Na₂SO₄ solution, the corrosion rate of a polymer‐coated mild steel sample is much lower than of the free metal substrate. These results suggest that phosphonic acid‐containing polysulfones might be interesting as anticorrosive coatings. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41890.     

Copper‐Catalyzed Trifluoromethylation of Aliphatic N‐Arylhydrazones: A Concise Synthetic Entry to 2‐Trifluoromethylindoles from Simple Aldehydes

The copper‐catalyzed C(sp²) H trifluoromethylation of N,N‐disubstituted hydrazones using the Togni reagent is demonstrated to proceed efficiently for aliphatic aldehyde‐derived substrates. The success of the reactions relied on the choice of the N,N‐diphenylamino group as the terminal hydrazone amino group where N,N‐dialkylamino groups were preferred for (hetero)aromatic aldehyde‐derived substrates. In addition, the trifluoromethylated N‐arylhydrazones are shown to be ideal substrates for Fischer indole synthesis allowing a straightforward, three‐step access to 2‐trifluoromethylindole derivatives from simple aldehydes.

     

Fast automated NMR spectroscopy of short-lived biological samples

Faster than death: NMR techniques that make use of nonlinear sampling and hyperdimensional processing enable the recording of complete NMR data sets for the automated assignment of the backbone and side-chain resonances of short-lived protein samples of cell lysates.     

Read-out of soft X-ray contact microscopy microradiographs by focused ion beam/scanning electron microscope

A novel focused ion beam-based technique is presented for the read-out of microradiographs of Caenorhabditis elegans nematodes generated by soft x-ray contact microscopy (SXCM). In previous studies, the read-out was performed by atomic force microscopy (AFM), but in our work SXCM microradiographs were imaged by scanning ion microscopy (SIM) in a focused ion beam/scanning electron microscope (FIB/SEM). It allows an ad libitum selection of a sample region for gross morphologic to nanometric investigations, with a sequence of imaging and cutting. The FIB/SEM is less sensitive to height variation of the relief, and sectioning makes it possible to analyse the sample further. The SXCM can be coupled to SIM in a more efficient and faster way than to AFM. Scanning ion microscopy is the method of choice for the read-out of microradiographs of small multicellular organisms.     

Grafting of polystyrene “from” and “through” surface modified titania nanoparticles

We report the surface modification of titania (TiO₂) nanoparticles with azo-based radical initiator and vinyl (acrylate) polymerizable groups. This is achieved through the reaction of the surface hydroxyl groups of the titania with acid halides. Polymer (specifically, polystyrene) was grafted “from” the surface using the azo-modified titania, and “through” the surface of the vinyl-modified surface. Both conventional radical and reversible addition-fragmentation chain transfer (RAFT) polymerizations were performed. The surface-modified titania and the polystyrene-titania nanocomposites were characterized using IR spectroscopy, thermogravimetric analysis and gel permeation chromatography.     

Synthesis,SAR and Unanticipated Pharmacological Profiles of Analogues of the mGluR5 Ago‐potentiator ADX‐47273

An iterative analogue library synthesis strategy rapidly developed comprehensive SAR for the mGluR5 ago‐potentiator ADX‐47273. This effort identified key substituents in the 3‐position of oxadiazole that engendered either mGluR5 ago‐potentiation or pure mGluR5 positive allosteric modulation. The mGluR5 positive allosteric modulators identified possessed the largest fold shifts (up to 27.9‐fold) of the glutamate CRC reported to date as well as providing improved physiochemical properties.

     

A density functional theory study of hydrogen recombination and hydrogen-deuterium exchange on Ga/H-ZSM-5

Density functional theory calculations have been carried out to determine the thermodynamic stability of various Ga species in gallium-exchanged ZSM-5, the thermodynamics of H₂ adsorption, and the most favorable pathway for H₂/D₂ exchange. The portion of the zeolite associated with Ga was represented by a cluster containing 7, 21, or 33 atoms. The B3LYP hybrid method was used to account for the effects of electron exchange and correlation. The most likely form of Ga expected in freshly exchanged and calcined ZSM-5 is ZGa(OH)₂. H₂ reduction of this species is projected to produce ZGa(H)(OH) and ZGa(H)₂. While the thermodynamics of H₂ desorption from ZGa(H)₂ are favorable, the process is projected to be slow because of a high activation barrier. The most favorable pathway for H₂/D₂ exchange over ZGa(H)₂ proceeds via Z(D)(Ga(H)₂(D)) as an intermediate. Similar calculations have been carried out for H₂/D₂ exchange over H-ZSM-5. This revised version was published online in June 2006 with corrections to the Cover Date.     

Development of [60] fullerene supported on silica catalysts for the photo-oxidation of alkenes

Simple or successive incipient wetness impregnation followed by heating at 180 °C is proved an efficient preparation method for dispersing effectively onto the silica surface various amounts of C₆₀ in the range 1–4% (w/w). BET, XRD, DRS, TGA, microelectrophoresis and photoluminescence have been used to characterize the photocatalysts prepared. A high dispersion was obtained for the quite stable supported C₆₀ phase, comprised mainly from relatively small or medium size C₆₀ clusters/aggregates. The photocatalytic activity was assessed in the singlet oxygen oxidation of alkenes by examining the photo-oxygenation of 2-methyl-2-heptene as a probe reaction. The catalytic tests were carried out at 0–5 °C in CH₃CN, under oxygen atmosphere and using a 300 W xenon lamp as the light source. The heterogeneous catalysts obtained were proved to be active in the photocatalytic oxidation of olefins via a ¹O₂ ene reaction. The catalysts exhibited significant conversion, turnover number and turnover frequency values, substantially higher than those achieved over the unsupported C₆₀. The conversion increases with the amount of the supported C₆₀ up to a value equal to 3% (w/w) and then it decreases whereas turnover number and turnover frequency decreases monotonically as the amount of the supported C₆₀ increases. The easy separation of these solid catalysts from the reaction mixture, the high activity and stability as well as the retained activity in subsequent catalytic cycles, make these supported catalysts suitable for a small-scale synthesis of fine chemicals.     

Application of adaptive comfort behaviors in Chilean social housing standards under the influence of climate change

Currently, energy performance indicators for buildings are associated with the primary energy source consumption, CO₂ emissions or net energy distribution, which together set the building’s energy efficiency. The evaluation is frequently based on setpoint temperatures and hours of operation. However, these fixed parameters are not suitable for social housing simulation as their performance tends to be in free running, excluding extremely cold or warm conditions. Therefore, a more successful assessment for the efficiency of these buildings is the users’ capability to live within adaptive comfort ranges without air conditioning systems. The aim of this research is to analyze new Chilean standards for sustainable social housing in the context of climate change using the adaptive comfort approach addressed in EN 15251:2007. Using EnergyPlus simulation software, 16 parametric series are analyzed for current conditions and validated against on-site measurements. Meanwhile, a prediction for the climate in 2050 has also been taken into account. The case study is the most widespread low cost dwelling model. The study demonstrates that the period of time within thermal comfort conditions varies substantially if analysis is done using the adaptive comfort standard or the Sustainable Construction Code (CCS) for Chilean housing. Considering climate change, the percentage of time fluctuates from ?19.00% to 24.30%. Concluding that the adaptive comfort model has a greater capacity to positively assess indoor temperatures for social housing in Central-Southern Chile. This research also establishes that it is possible to provide homes where standards are improved within comfort conditions without using artificial means, 99.67% of the time currently and 88.89% in the future.