Influence of Perfluorinated End Groups on the SFRD of [Pt(cod)Me(CnF2n+1)] onto Porous Al2O3 in CO2 under Reductive Conditions

The optimized synthesis of a range of cyclooctadiene‐stabilized Pt complexes that contained different perfluoro‐alkane chains, [Pt(cod)Me(C_nF_2n+1)], is presented. These metal–organic compounds were employed in the so‐called supercritical fluid reactive deposition (SFRD) in CO₂ under reductive conditions to generate metallic nanoparticles on aluminum oxide as a porous support. Thus, Al₂O₃‐supported Pt nanoparticles with a narrow particle‐size distribution were obtained. At a reduction pressure of 15.5 MPa and a temperature of 353 K, particle diameters of d₅₀=2.3–2.8 nm were generated. Decreasing the pressure during the reduction reaction led to slightly larger particles whilst decreasing the amount of organometallic precursor in CO₂ yielded a decrease in the particle size from x₅₀=3.2 nm to 2.6 nm and a particle‐size distribution of 2.2 nm. Furthermore, substitution of the CH₃ end group by the C_nF_2n+1 end groups led to a significant drop in Pt loading of about 50 %. Within the series of perfluorinated end groups that were considered, the Pt complex that contained a branched perfluoro‐isopropyl group showed the most‐interesting results when compared to the control precursor, [Pt(cod)Me₂] ( 1 ).     

Anisotropic swelling of hydrogel nanowires based on poly(vinylpyrrolidone) fabricated by single‐particle nanofabrication technique

We report a hydrogel nanowire based on poly(vinylpyrrolidone) (PVP) and N,N'‐methylenebis(acrylamide) (MBA), which have anisotropic swelling ratio for radius and length direction. The PVP/MBA nanowires were fabricated by single particle nanofabrication technique, which is a technique for the fabrication of polymeric nanowires using the single ion event, that cause the crosslinking reaction of polymer chains within the ion tracks along the ion paths; furthermore the size (length and radius) of the nanowires was controlled by changing the film thickness and amount of MBA crosslinker. The swelling behaviors in air and water were observed using atomic force microscopy. The PVP/MBA nanowires exhibited anisotropic swelling along the length and radius in aqueous environments, because the hydrogel nanowires consisted of crosslinked networks with inhomogeneous crosslinking points, which reflected the initial energy distribution from incident an ion within the ion track. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1950–1956     

Bis-spirochromanones as potent inhibitors of Mycobacterium tuberculosis: synthesis and biological evaluation

Molecular Diversity - On the basis of reported antimycobacterial property of chroman-4-one pharmacophore, a series of chemically modified bis-spirochromanones were synthesized starting from...     

Degradation in polytetrafluoro ethylene by 62 mev protons

The aim of our study is to describe the dose dependent proton induced modifications in Polytetrafluoro ethylene (PTFE) by using Fourier Transform Infra-red spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC) and X-ray diffraction analysis (XRD). The shifting of the main peak along with a decrease in its intensity, the decrease in thermal stability and melting point and the formation of stable free radicals were observed in the polymer by proton irradiation.