Crosslinking effects on hybrid organic–inorganic proton conducting membranes based on sulfonated polystyrene and polysiloxane

New hybrid semi‐interpenetrating proton‐conducting membranes were obtained using sulfonated polystyrene (SPS) and inorganic–organic polysiloxane phases with the aim of improving the mechanical and thermal characteristics of the pristine polymer and to study the effects of crosslinking in the latter phase in several of their properties, mainly proton conductivity. Siloxane phases were prepared using poly(dimethylsiloxane) (PDMS) and PDMS with tetraethoxysilane (TEOS) or phenyltrimethoxysilane (PTMS) as crosslinking agents. To study the crosslinking effect, membranes were prepared with different TEOS:PDMS and PTMS:PDMS mole ratios. The films obtained were characterized by FTIR, ²⁹Si‐HPDEC MAS‐NMR, ¹³C‐CP‐MAS NMR, elemental and thermal analyses. Certain properties, such as water uptake (WU), ion exchange capacity (IEC) and the state of the water, were determined. The proton conductivity was measured at different temperatures (30°C and 80°C) and relative humidities (50–95%). The water content of the hybrid membranes declined significantly, compared with the SPS membranes, depending on the nature and amount of siloxane phase added. Nonetheless, the conductivity values remained relatively high (>100 mS cm^?1 at 80°C and 95% RH) when compared to Nafion®117 presumably because of the formation of well developed proton channels, which makes them potentially promising as proton exchange membranes for fuel cells. These membranes proved to be thermally stable up to 350°C. Scanning electron microscopy (SEM) and scanning electrochemical microscopy (SECM) were used to characterize the hybrid membranes microstructures; the latter provided contrast for the conductive domains. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis,characterization and X-ray crystal structure determination of cyclopalladated [Csp2,N,N′]−, zwitterionic and chelated compounds in the reaction of 3,5-diphenyl-N-alkylaminopyrazole derived ligands with Pd(II)

The synthesis of two N-alkylaminopyrazole ligands, 1-[2-(diethylamino)ethyl]-3,5-diphenylpyrazole (L1) and 1-[2-(dioctylamino)ethyl]-3,5-diphenylpyrazole (L2), is reported. These ligands present, a priori, one pyrazole nitrogen and one amine nitrogen as potential donor atoms. However, in the reaction of the ligands (L1 and L2) with [PdCl₂(CH₃CN)₂] one of the C_phenyl atoms can also behave as a donor atom. As a result, we have obtained the formation of three different compounds for each one of the ligands: chelated ([PdCl₂(L)] L = L1 (1a), L2 (2a)), zwitterionic ([PdCl₃(LH)] LH = LH1 (1b), LH2 (2b)), and cyclopalladated compounds ([PdCl(LC)] (LC = LC1 (1c), LC2 (2c)). The solid-state structures for 1a, 1b and 1c were determined by single crystal X-ray diffraction methods. The potentially [C,N,N′]^? ligand is coordinated through the N_pz and the N_amino to the metal atom for 1a, through the N_pz for 1b, and through the N_pz, the N_amino and a C_phenyl for 1c.     

Synthesis,Structural Characterization and Spectroscopic Properties of [Pt(bddn)]Cl<Subscript>2</Subscript> · 3.5H<Subscript>2</Subscript>O (bddn = 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane)

Abstract The reaction of the potentially tetradentate ligand 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane (bddn) with [PtCl₂(CH₃CN)₂] yields a mixture of complexes, where the ligand acts as bidentate SS, or tetradentate 2NS or NSSN. This mixture of complexes SS, 2NS, and NSSN was crystallized with dichloromethane/n-pentane (1:1) and crystals of [Pt(bddn)]Cl₂ (isomer NSSN) were obtained. The complex has been characterized by elemental analyses, mass spectrometry, conductivity, IR, ¹H, ¹³C{¹H}, ¹H{¹⁹⁵Pt}, ¹⁹⁵Pt{¹H}NMR, HSQC and NOESY spectroscopies, and X-ray diffraction. Compound [PtCl₂(bddn)] · 3.5H₂O crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 15.430(7) ?, b = 17.405(4) ?, c = 18.887(7) ?, β = 91.24(2)°, V = 5071(3) ?³, Z = 4, R ₁ = 0.0354, wR₂ = 0.1034. This compound consist of discrete cations [Pt(bddn)]²⁺, Cl⁻ anions and water molecules of crystallization. The platinum(II) is tetracoordinated by two azine nitrogen atoms and two sulfur atoms of the thioether-pyrazole ligand, in a distorted square planar geometry. Graphical Abstract Synthesis, Structural Characterization and Spectroscopic Properties of [Pt(bddn)]Cl ₂ · 3.5H ₂ O (bddn = 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane) Antonio de Leon, Josefina Pons*, Jordi García-Antón, Xavier Solans, Mercè Font-Bardia, Josep Ros* Reaction of the ligand 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane (bddn) with [PtCl₂(CH₃CN)₂], yields a mixture of complexes. The mixture was crystallized with dichloromethane/pentane (1:1) and crystals of [Pt(bddn)]Cl₂ · 3.5 H₂O was obtained. Electronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.     

Electron Kinetic Entropy across Quasi-Perpendicular Shocks

We use Magnetospheric Multiscale (MMS) data to study electron kinetic entropy per particle Se across Earth’s quasi-perpendicular bow shock. We have selected 22 shock crossings covering a wide range of shock conditions. Measured distribution functions are calibrated and corrected for spacecraft potential, secondary electron contamination, lack of measurements at the lowest energies and electron density measurements based on plasma frequency measurements. All crossings display an increase in electron kinetic entropy across the shock ΔSe being positive or zero within their error margin. There is a strong dependence of ΔSe on the change in electron temperature, ΔTe, and the upstream electron plasma beta, βe. Shocks with large ΔTe have large ΔSe. Shocks with smaller βe are associated with larger ΔSe. We use the values of ΔSe, ΔTe and density change Δne to determine the effective adiabatic index of electrons for each shock crossing. The average effective adiabatic index is 〈γe〉=1.64±0.07.     

Novel hydridotris(pyrazolyl)borate ruthenium(II) complexes containing the water-soluble phosphane 1,3,5-triaza-7-phosphaadamantane: Synthesis and evaluation of DNA binding properties

A series of half-sandwich ruthenium(II) complexes containing κ³(N,N,N)-hydridotris(pyrazolyl)borate (κ³(N,N,N)-Tp) and the water-soluble phosphane 1,3,5-triaza-7-phosphaadamantane (PTA) [RuX{κ³(N,N,N)-Tp}(PPh₃)_2−n(PTA)_n] (n = 2, X = Cl (1), n = 1, X = Cl (2), I (3), NCS (4), H (5)) and [Ru{κ³(N,N,N)-Tp}(PPh₃)(PTA)L][PF₆] (L = NCMe (6), PTA (7)) have been synthesized. Complexes containing 1-methyl-3,5-diaza-1-azonia-7-phosphaadamantane(m-PTA) triflate [RuCl{κ³(N,N,N)-Tp}(m-PTA)₂][CF₃SO₃]₂ (8) and [RuX{κ³(N,N,N)-Tp}(PPh₃)(m-PTA)][CF₃SO₃] (X = Cl (9), H (10)) have been obtained by treatment, respectively, of complexes 1, 2 and 5 with methyl triflate. Single crystal X-ray diffraction analysis for complexes 1, 2 and 4 have been carried out. DNA binding properties by using a mobility shift assay and antimicrobial activity of selected complexes have been evaluated.     

Conversion of Phthalimides to Isoindolines by Diborane

Summary. Reduction of N-alkylsubstituted phthalimides to the corresponding isoindolines by means of diborane is herein described.