• Title, Summary, Keyword: anion

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Anion Exchange Membrane Having Permselectivity specific Anion in Electrodialysis

  • Sata, Toshikatsu
    • Proceedings of the Membrane Society of Korea Conference
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    • pp.1-6
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    • 1998
  • To change permselectivity between anions through the anion exchange membrane in electrodialysis, the various modified anion exchange membranes were prepared: highly crosslinked anion exchange membranes, anion exchange membranes having benzyl trialkylammonium groups with different carbon number of alkyl chain as anion exchange groups and anion exchange membranes having pyridinium groups with a hydrophilic or hydrophobic substituent at a different position as anion exchange groups. It became clear from the evaluation of these membranes that the degree of the hydrophilicity of the anion exchange membranes greatly affects the permselectivity between two artions. To increase the hydrophiticity of the anion exchange membranes further, electrodialysis was carried out in the presence of ethylene glycols and the permeation of strongly hydrated anions increased and that of less-hydrated anions decreased. It became clear that the change in the permselectivity between two artions is due to the change in the affinity of anions to the membranes, not the change in mobility ratio of the anions in the membranes phase.

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Ionic Conductivity of Anion Receptor Grafted Siloxane Polymers for Solid Polymer Electrolytes

  • Lee, Won-Sil;Kim, Dong-Wook;Lee, Chang-In;Woo, Seong-Ihl;Kang, Yong-Ku
    • Journal of Electrochemical Science and Technology
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    • v.2 no.1
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    • pp.26-31
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    • 2011
  • We have prepared siloxane polymers grafted with trifluoromethane-sulfonylamide and oligoether side chains for solid polymer electrolytes with enhanced ionic conductivity. The grafted trifluoromethane sulfonylamide groups seem to be effective as an anion recepting site to enhance the ionic conductivity of the solid polymer electrolyte. The anion receptor grafted siloxane polymers showed one order of magnitude higher ionic conductivity than the siloxane polymers without anion receptor grafts. The fitting parameter A of the VTF plot which was related to the carrier density of the electrolyte increased with increasing the number of grafted anion receptor. The results of experiment indicate that the anion-complexing site of the anion receptor grafted polymer host effectively traps the anions. The anion receptor grafted polymer was found to be a promising material for lithium polymer batteries.

Inversion Barriers of Methylsilole and Methylgermole Monoanions

  • Pak, Youngshang;Ko, Young Chun;Sohn, Honglae
    • Bulletin of the Korean Chemical Society
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    • v.33 no.12
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    • pp.4161-4164
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    • 2012
  • Density functional MO calculations for the methylsilole anion of $[C_4H_4SiMe]^-$ and methylgermole anion of $[C_4H_4SiMe]^-$ at the B3LYP (full)/6-311+$G^*$ level (GAUSSIAN 94) were carried out and characterized by frequency analysis. The ground state structure for the methylsilole anion and methylgermole anion is that the methyl group is pyramidalized with highly localized structure. The difference between the calculated $C_{\alpha}-C_{\beta}$ and $C_{\beta}-C_{\beta}$ distances are 9.4 and 11.5 pm, respectively. The E-Me vector forms an angle of $67.9^{\circ}$ and $78.2^{\circ}$ with the $C_4E$ plane, respectively. The optimized structures of the saddle point state for the methylsilole anion and methylgermole anion have been also found as a planar with highly delocalized structure. The optimized $C_{\alpha}-C_{\beta}$ and $C_{\beta}-C_{\beta}$ distances are nearly equal for both cases. The methyl group is located in the plane of $C_4E$ ring and the angle between the E-Me vector and the $C_4E$ plane for the methylsilole anion and methylgermole anion is $2.0^{\circ}$ and $2.3^{\circ}$, respectively. The energy difference between the ground state structure and the transition state structure is only 5.1 kcal $mol^{-1}$ for the methylsilole anion. However, the energy difference of the methylgermole anion is 14.9 kcal $mol^{-1}$, which is much higher than that for the corresponding methylsilole monoanion by 9.8 kcal $mol^{-1}$. Based on MO calculations, we suggest that the head-to-tail dimer compound, 4, result from [2+2] cycloaddition of silicon-carbon double bond character in the highly delocalized transition state of 1. However, the inversion barrier for the methylgermole anion is too high to dimerize.

Molecular Aspects of Organic Ion Transporters in the Kidney

  • Cha, Seok-Ho;Endou, Hitoshi
    • The Korean Journal of Physiology and Pharmacology
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    • v.5 no.2
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    • pp.107-122
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    • 2001
  • A function of the kidney is elimination of a variety of xenobiotics ingested and wasted endogenous compounds from the body. Organic anion and cation transport systems play important roles to protect the body from harmful substances. The renal proximal tubule is the primary site of carrier-mediated transport from blood into urine. During the last decade, molecular cloning has identified several families of multispecific organic anion and cation transporters, such as organic anion transporter (OAT), organic cation transporter (OCT), and organic anion-transporting polypeptide (oatp). Additional findings also suggested ATP-dependent organic ion transporters such as MDR1/P-glycoprotein and the multidrug resistance-associated protein (MRP) as efflux pump. The substrate specificity of these transporters is multispecific. These transporters also play an important role as drug transporters. Studies on their functional properties and localization provide information in renal handling of drugs. This review summarizes the latest knowledge on molecular properties and pharmacological significance of renal organic ion transporters.

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Pharmacological Activities of Flavonoids(IV) - Inhibitory Actions of Leukocyte Migration, Superoxide Anion Production and Lipid Peroxidation - (Flavonoids의 약리작용 (IV) - 백혈구유주, superoxide anion 및 과산화지질 생성 억제작용 -)

  • 김창종;정현삼;정진모
    • YAKHAK HOEJI
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    • v.35 no.3
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    • pp.165-173
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    • 1991
  • Effects of eight flavonoids and their related compounds on leukocytes migration, superoxide anion production and lipid peroxidation in the phagocytosis of latex beads or E. coli by guinea pig peritoneal exudate cells were studied in vitro. It shows that most of flavonoids generally inhibited the leukocytes migration and production of superoxide anion and malonedialdehydes. Their inhibitory activities in the phagocytosis of latex beads had more active than that of E. coli. Quercetin has the most inhibitory activity in leukocytes migration and production of superoxide anion and lipid peroxides at the concentration of 1, 2 and 10 $\mu{M}$. Catechin and rutin at the concentration of 2 and 10 $\mu{M}$ inhibited significantly the production of superoxide anion and lipid peroxides. Flavone, catechin, naringin and rutin at the concentration of 2 and 10 $\mu{M}$ inhibited significantly the leukocytes migration.

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Anion Receptors with 2-Imidazolidone Molecular Scaffold

  • Kim, Hyung-Il;Kang, Jong-Min
    • Bulletin of the Korean Chemical Society
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    • v.28 no.9
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    • pp.1531-1534
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    • 2007
  • Anion receptor based on 2-imidazolidone molecular scaffold has been synthesized. Anion binding studies carried out using 1H NMR and UV?vis spectroscopy revealed that this receptor 6 displays selectivity for the for the oxyanions such as acetate and dihydrogenphosphate ions and the affinity for the anions simply reflects the basicity of anions.

Versatilities of Calix[4]pyrrole Based Anion Receptors

  • Lee, Chang-Hee
    • Bulletin of the Korean Chemical Society
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    • v.32 no.3
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    • pp.768-778
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    • 2011
  • Calixpyrroles and related macrocycles are non-planer synthetic anion receptors that have attracted considerable attentions in recent years. Although the synthesis of calix[4]pyrrole (known as meso-octamethylporphyrinogen) was reported more than 100 years ago, the anion binding properties were first discovered in 1996. The simple calix[4]pyrroles can be synthesized in single step in high yield by condensation of pyrrole with acetone. The compounds showed preferential binding for halide anions including fluoride, phosphate, carboxylate, and chloride in organic media. Efforts to improve the anion affinity of calix[4]pyrrole and to enhance its selectivity have led to the synthesis of a variety of new calixpyrrole derivatives. Among the various modifications, introduction of straps on one side of the calix[4]pyrroles are the most effective. Incorporation of aromatic rings other than pyrroles also exhibited interesting binding behaviour. Introduction of signalling units as part of the strapping element enable to detect the anions on chromogenic or fluorogenic fashion. Finding of the anion transport properties across the membrane and cytotoxic effects of the calix[4]pyrroles open new window for calixpyrrole-related research. The polymer-incorporated systems have also been employed as anion complexants in solvent-solvent extraction. These old, yet easy-to-make macrocycles have well advanced more recently with the discovery of the ion-pair complexation properties. In this review, the synthetic developments and anion binding properties of calixpyrroles for the last decades will be discussed and will cover the advances in calixpyrrole chemistry.