Sulphonated polystyrene ethylene butylene polystyrene(SPSEBS)prepared with 35%sulphonation was found to be highly elastic and enlarged up to 300%-400%of its initial length.It absorbed over 110%of water by weight.A major drawback of this membrane is its poor mechanical properties which are not adequate for use as polymer electrolytes in fuel cells.To overcome this,SPSEBS was blended with poly(vinylidene fluoride)(PVDF),a hydrophobic polymer.The blend membranes showed better mechanical properties than the base polymer.The effect of PVDF content on water uptake,ion exchange capacity and proton conductivity of the blend membranes was investigated.This paper presents the results of recent studies applied to develop an optimized in-house membrane electrode assembly(MEA)preparation technique combining catalyst ink spraying and assembly hot pressing.Easy steps were chosen in this preparation technique in order to simplify the method,aiming at cost reduction.The open circuit voltage for the cell with SPSEBS is 0.980 V which is higher compared to that of the cell with Nafion 117(0.790 V).From this study,it is concluded that a polymer electrolyte membrane suitable for proton exchange membrane fuel cell(PEMFC)and direct methanol fuel cell(DMFC)application can be obtained by blending SPSEBS and PVDF in appropriate proportions.The methanol permeability and selectivity showed a strong influence on DMFC performance. 相似文献
Diastereoselective synthesis of a series of (Z)-1-[3-aryl-2-(phenylsulfanyl)-2-oxiranyl]-1-ethanones was effected from the reaction of (Z)-4-aryl-3-(phenylsulfanyl)-3-buten-2-ones with alkaline hydrogen peroxide in tetrahydrofuran. The stereochemistry of the oxiranes has been deduced from two-dimensional NOESY spectrum. 相似文献
Synthesis of novel glycodendrimer scaffolds containing hypervalent sugar pyranosides and triazole bridging points is described. Dendrimers with a greater number of bridging triazole units and α-d-glycopyranosyl surface groups exhibit better anti-arthritic and anti-inflammatory activity than dendrimers with less number of triazole and α-d-glycopyranosyl units. 相似文献
The syntheses of various types of 1,2,3-triazole-based dendrimers 1–4 with sugar pyranosylazides and N-ethyl and N-heptylazides as a surface unit and benzene-1,3,5-tricorboxlyic amide as core unit through click chemistry approach are described. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file. 相似文献
A facile efficient synthesis of novel 3-aryl-5,6-dihydro-1,4,2-oxathiazin-6-ols from the reaction of (E)-N-hydroxyarylimidoyl chlorides and 1,4-dithiane-2,5-diol in the presence of triethylamine is described. This transformation presumably proceeds via in situ generation of 2-mercaptoacetaldehyde and nitrile oxide and their concomitant [3+3] annulation. 相似文献
Design of highly efficient phosphorescent emitters based on metal‐ and heavy atom‐free boron compounds has been demonstrated by taking advantage of the singlet fission process. The combination of a suitable molecular scaffold and appropriate electronic nature of the substituents has been utilized to tailor the phosphorescence emission properties in solution, neat solid, and in doped PMMA thin films. 相似文献
The optimized molecular structures, harmonic vibrational wavenumbers, and the corresponding vibrational assignments of (1S,2S)-tramadol and (1R,2R)-tramadol are computationally examined using the B3LYP density functional theory method together with the standard 6–311++G(d,p) and def2-TVZP basis sets. The optimized structures show that phenolic rings of both 1R,2R and 1S,2S tramadol adopt planar geometry, which are slightly distorted due to the substitution at the meta-position; and the six-membered cyclohexane adopts a slightly distorted chair conformation. The 1S,2S enantiomer is energetically more favorable than 1R,2R with the energy differences of 1.32 and 1.03 kcal/mol obtained at B3LYP/6–311++G(d,p) and B3LYP/Def2-TVZP levels, respectively. The analysis of the binding pocket in the silico molecular docking with the m-opioid receptor shows that it originated two clusters with the 1S,2S enantiomer and one cluster with the 1R,2R enantiomer of tramadol. The results point to a more stable complex of the m-opioid receptor with the 1R,2R enantiomer of tramadol. 相似文献
A series of N-dibenzosuberene substituted aroyl selenourea ligands L1–L3 and their Ru(II) (η6-p-cymene) complexes 1–3, [Ru(II) (η6-p-cymene) L] (L?=?monodentate aroyl selenourea ligand) were synthesized and characterized. The molecular structures of the ligand L3 and complex 3 were confirmed by single-crystal XRD method. The single-crystal XRD study results revealed that aroyl selenourea ligand coordinates with ruthenium via Se neutral monodentate atom. In vitro DNA interaction studies were investigated by UV–Visible and fluorescence spectroscopic methods which showed that the intercalative mode of binding is in the order of 3?>?2?>?1 with the Ru(II) (η6-p-cymene) complexes. The binding affinity of the bovine serum albumin with complexes was calculated using spectroscopic methods. Quantum chemical computations were made using DFT (density functional theory), BL3YP; LANL2DZ basis set in order to determine the frontier molecular orbital parameters and MESP for the newly synthesized complexes. The complexes 1–3 have shown intensive cytotoxicity against the cancer lines HepG-2 and A549 under in vitro conditions. Complex 3 (IC50?=?62 μM) has shown significant cytotoxic activity against HepG-2 compared to cisplatin standard drug. The complexes also examined for their antimicrobial activity. The complex 2 exhibited good activity against B. subtilis (MIC: 13.60 μg/mL), E. coli (MIC: 8.01 μg/mL) and A. flavus (MIC?=?15.60 μg/mL), respectively, compared to reference drugs Streptomycin and Ketoconazole.