Sulfonium

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Johan Jacquemin - One of the best experts on this subject based on the ideXlab platform.

  • acyclic and cyclic alkyl and ether functionalised Sulfonium ionic liquids based on the tfsi and fsi anions as potential electrolytes for electrochemical applications
    ChemPhysChem, 2018
    Co-Authors: Sinead Murphy, Alex R Neale, Peter Goodrich, Christopher Hardacre, Johan Jacquemin, Flavien Ivol, Fouad Ghamouss
    Abstract:

    This work provides a study based on acyclic and cyclic Sulfonium ionic liquids (ILs) with alkyl and ether-functionality on the cation paired with the bis{(trifluoromethyl)sulfonyl}imide, [TFSI]- , or the bis(fluorosulfonyl)imide, [FSI]- , as the counter anion. Herein, thermophysical characterisation of nine Sulfonium-based ILs concerning the density, viscosity and conductivity and thermal properties including phase transition behaviour and decomposition temperature is reported. The electrochemical stability of the ILs was also measured by cyclic voltammetry at a glassy carbon macro-disk electrode. All of the ILs showed low melting point, low viscosity and good conductivity and could serve as potential electrolytes for energy storage devices.

  • an ether functionalised cyclic Sulfonium based ionic liquid as an electrolyte for electrochemical double layer capacitors
    Journal of Power Sources, 2016
    Co-Authors: Alex R Neale, Andrea Balducci, Stefano Passerini, Christoph Schutter, Peter Goodrich, Christopher Hardacre, Sinead Murphy, Johan Jacquemin
    Abstract:

    A novel cyclic Sulfonium cation-based ionic liquid (IL) with an ether-group appendage and the bis{(trifluoromethyl)sulfonyl}imide anion was synthesised and developed for electrochemical double layer capacitor (EDLC) testing. The synthesis and chemical-physical characterisation of the ether-group containing IL is reported in parallel with a similarly sized alkyl-functionalised Sulfonium IL. Results of the chemical-physical measurements demonstrate how important transport properties, i.e. viscosity and conductivity, can be promoted through the introduction of the ether-functionality without impeding thermal, chemical or electrochemical stability of the IL. Although the apparent transport properties are improved relative to the alkyl-functionalised analogue, the ether-functionalised Sulfonium cation-based IL exhibits moderately high viscosity, and poorer conductivity, when compared to traditional EDLC electrolytes based on organic solvents (propylene carbonate and acetonitrile). Electrochemical testing of the ether-functionalised Sulfonium IL was conducted using activated carbon composite electrodes to inspect the performance of the IL as a solvent-free electrolyte for EDLC application. Good cycling stability was achieved over the studied range and the performance was comparable to other solvent-free, IL-based EDLC systems. Nevertheless, limitations of the attainable performance are primarily the result of sluggish transport properties and a restricted operative voltage of the IL, thus highlighting key aspects of this field which require further attention.

Mario B Pinto - One of the best experts on this subject based on the ideXlab platform.

  • binding of Sulfonium ion analogues of di epi swainsonine and 8 epi lentiginosine to drosophila golgi alpha mannosidase ii the role of water in inhibitor binding
    Proteins, 2007
    Co-Authors: Nag S. Kumar, Douglas A Kuntz, Xin Wen, Mario B Pinto
    Abstract:

    Retaining glycosidases operate by a two-step catalytic mechanism in which the transition states are characterized by buildup of a partial positive charge at the anomeric center. Sulfonium-ion analogues of the naturally occurring glycosidase inhibitors, swainsonine and 8-epi-lentiginosine, in which the bridgehead nitrogen atom is replaced by a Sulfonium-ion, were synthesized in order to test the hypothesis that a Sulfonium salt carrying a permanent positive charge would be an effective glycosidase inhibitor. Initial prediction based on computational docking indicated three plausible binding modes to Drosophila Golgi α-mannosidase II (dGMII), the most likely being close to that of swainsonine. Observation of the binding of di-epi-thioswainsonine and 8-epi-thiolentiginosine to dGMII from crystallographic data, however, revealed an orientation different from swainsonine in the active site. Screening these two compounds against dGMII shows that they are inhibitors with IC50 values of 2.0 and 0.014 mM, respectively. This dramatic difference in affinity between the two compounds, which differ by only one hydroxyl group, is rationalized in terms of bound water molecules and the water molecule substructure in the active site, as identified by comparison of high resolution X-ray crystal structures of several dGMII-inhibitor complexes. Proteins 2008. © 2007 Wiley-Liss, Inc.

  • binding of Sulfonium ion analogues of di epi swainsonine and 8 epi lentiginosine to drosophila golgi alpha mannosidase ii the role of water in inhibitor binding
    Proteins, 2007
    Co-Authors: Nag S. Kumar, Douglas A Kuntz, Xin Wen, Mario B Pinto
    Abstract:

    Retaining glycosidases operate by a two-step catalytic mechanism in which the transition states are characterized by buildup of a partial positive charge at the anomeric center. Sulfonium-ion analogues of the naturally occurring glycosidase inhibitors, swainsonine and 8-epi-lentiginosine, in which the bridgehead nitrogen atom is replaced by a Sulfonium-ion, were synthesized in order to test the hypothesis that a Sulfonium salt carrying a permanent positive charge would be an effective glycosidase inhibitor. Initial prediction based on computational docking indicated three plausible binding modes to Drosophila Golgi alpha-mannosidase II (dGMII), the most likely being close to that of swainsonine. Observation of the binding of di-epi-thioswainsonine and 8-epi-thiolentiginosine to dGMII from crystallographic data, however, revealed an orientation different from swainsonine in the active site. Screening these two compounds against dGMII shows that they are inhibitors with IC(50) values of 2.0 and 0.014 mM, respectively. This dramatic difference in affinity between the two compounds, which differ by only one hydroxyl group, is rationalized in terms of bound water molecules and the water molecule substructure in the active site, as identified by comparison of high resolution X-ray crystal structures of several dGMII-inhibitor complexes.

  • selection of a high energy bioactive conformation of a Sulfonium ion glycosidase inhibitor by the enzyme glucoamylase g2
    Journal of the American Chemical Society, 2003
    Co-Authors: Margaret A Johnson, Morten T Jensen, Birte Svensson, Mario B Pinto
    Abstract:

    Transferred nuclear Overhauser effect and rotating-frame Overhauser enhancement NMR spectroscopies are used to probe the conformation of a bicyclic Sulfonium ion, which is an analogue of the naturally occurring glycosidase inhibitor castanospermine, bound to the enzyme glucoamylase G2. Enzyme inhibition assays indicate that the bicyclic Sulfonium ion is a slightly better inhibitor (Ki = 1.32 mM) of glucoamylase G2 than the naturally occurring Sulfonium-ion glycosidase inhibitor, salacinol, with a Ki value of 1.7 mM. The NMR results are interpreted in terms of the selection by the enzyme of a high-energy conformation of the ligand that is already represented in the ensemble of free-ligand conformations.

  • synthesis of 1 4 anhydro d xylitol heteroanalogues of the naturally occurring glycosidase inhibitor salacinol and their evaluation as glycosidase inhibitors
    Canadian Journal of Chemistry, 2002
    Co-Authors: Ahmad Ghavami, Morten T Jensen, Birte Svensson, Blair D Johnston, Matthew D Maddess, Sarah M Chinapoo, Mario B Pinto
    Abstract:

    The syntheses of two 1,4-anhydro-D-xylitol heteroanalogues (8 and 9) of the naturally occurring Sulfonium ion, salacinol (3), containing a sulfur or nitrogen atom in the ring are described. Salacin...

  • synthesis and conformational analysis of a Sulfonium ion analogue of the glycosidase inhibitor castanospermine
    Journal of the American Chemical Society, 2000
    Co-Authors: Lars Svansson, Blair D Johnston, And Brian O Patrick, Mario B Pinto
    Abstract:

    The synthesis of a bridgehead Sulfonium salt analogue (7) of the indolizidine alkaloid castanospermine has been achieved by a multistep procedure starting from 5-thio-d-glucopyranose pentaacetate. The compound was intended to test the theory that glycosidase inhibitory activity of the indolizidine alkaloids might be due to electrostatic stabilization of a positively charged species in the enzyme active site and that a Sulfonium salt carrying a permanent positive charge might be advantageous. The structure of the bicylic Sulfonium salt (7) [3(R),4(S),5(R),6(S)-3,4,5-trihydroxy-cis-1-thioniabicyclo[4.3.0]nonane perchlorate] was confirmed by X-ray crystallography. Analysis of the 1H NMR spectrum of compound 7 indicated that a similar conformation was adopted in solution. This conformational preference, with hydroxyl groups in the more sterically hindered axial orientations, has been attributed to the dominance of stabilizing electrostatic interactions between the oxygen atoms and the Sulfonium center.

Nag S. Kumar - One of the best experts on this subject based on the ideXlab platform.

  • binding of Sulfonium ion analogues of di epi swainsonine and 8 epi lentiginosine to drosophila golgi alpha mannosidase ii the role of water in inhibitor binding
    Proteins, 2007
    Co-Authors: Nag S. Kumar, Douglas A Kuntz, Xin Wen, Mario B Pinto
    Abstract:

    Retaining glycosidases operate by a two-step catalytic mechanism in which the transition states are characterized by buildup of a partial positive charge at the anomeric center. Sulfonium-ion analogues of the naturally occurring glycosidase inhibitors, swainsonine and 8-epi-lentiginosine, in which the bridgehead nitrogen atom is replaced by a Sulfonium-ion, were synthesized in order to test the hypothesis that a Sulfonium salt carrying a permanent positive charge would be an effective glycosidase inhibitor. Initial prediction based on computational docking indicated three plausible binding modes to Drosophila Golgi α-mannosidase II (dGMII), the most likely being close to that of swainsonine. Observation of the binding of di-epi-thioswainsonine and 8-epi-thiolentiginosine to dGMII from crystallographic data, however, revealed an orientation different from swainsonine in the active site. Screening these two compounds against dGMII shows that they are inhibitors with IC50 values of 2.0 and 0.014 mM, respectively. This dramatic difference in affinity between the two compounds, which differ by only one hydroxyl group, is rationalized in terms of bound water molecules and the water molecule substructure in the active site, as identified by comparison of high resolution X-ray crystal structures of several dGMII-inhibitor complexes. Proteins 2008. © 2007 Wiley-Liss, Inc.

  • binding of Sulfonium ion analogues of di epi swainsonine and 8 epi lentiginosine to drosophila golgi alpha mannosidase ii the role of water in inhibitor binding
    Proteins, 2007
    Co-Authors: Nag S. Kumar, Douglas A Kuntz, Xin Wen, Mario B Pinto
    Abstract:

    Retaining glycosidases operate by a two-step catalytic mechanism in which the transition states are characterized by buildup of a partial positive charge at the anomeric center. Sulfonium-ion analogues of the naturally occurring glycosidase inhibitors, swainsonine and 8-epi-lentiginosine, in which the bridgehead nitrogen atom is replaced by a Sulfonium-ion, were synthesized in order to test the hypothesis that a Sulfonium salt carrying a permanent positive charge would be an effective glycosidase inhibitor. Initial prediction based on computational docking indicated three plausible binding modes to Drosophila Golgi alpha-mannosidase II (dGMII), the most likely being close to that of swainsonine. Observation of the binding of di-epi-thioswainsonine and 8-epi-thiolentiginosine to dGMII from crystallographic data, however, revealed an orientation different from swainsonine in the active site. Screening these two compounds against dGMII shows that they are inhibitors with IC(50) values of 2.0 and 0.014 mM, respectively. This dramatic difference in affinity between the two compounds, which differ by only one hydroxyl group, is rationalized in terms of bound water molecules and the water molecule substructure in the active site, as identified by comparison of high resolution X-ray crystal structures of several dGMII-inhibitor complexes.

  • Synthesis of thioswainsonine as a potential glycosidase inhibitor
    Carbohydrate Research, 2006
    Co-Authors: Nag S. Kumar, B. Mario Pinto
    Abstract:

    Abstract The synthesis of a bicyclic Sulfonium-ion analogue of a naturally occurring glycosidase inhibitor, swainsonine, in which the bridgehead nitrogen atom is replaced by a Sulfonium ion, has been achieved by a multi-step synthesis starting from 1,4-anhydro-2,3-di- O -benzyl-4-thio- d -lyxitol. The synthetic strategy relies on the intramolecular displacement of a leaving group on a pendant acyclic chain by a cyclic thioether. This bicyclic Sulfonium salt will serve as a candidate to test the hypothesis that a Sulfonium salt carrying a permanent positive charge would be an effective glycosidase inhibitor.

  • Synthesis of a Sulfonium ion analogue of the glycosidase inhibitor swainsonine.
    The Journal of organic chemistry, 2006
    Co-Authors: Nag S. Kumar, B. Mario Pinto
    Abstract:

    The synthesis of a bicyclic Sulfonium ion analogue of a naturally occurring indolizidine alkaloid, swainsonine, in which the bridgehead nitrogen atom is replaced by a Sulfonium ion, has been achieved by a multistep synthesis starting from (2S,3S,4R)-2,3-dibenzyloxy-4-formaldehyde-thiolane. The synthetic strategy relies on the intramolecular displacement of a leaving group on a pendant acyclic chain by a cyclic thioether. This bicyclic Sulfonium salt provides a candidate with which to further probe the hypothesis that a Sulfonium salt carrying a permanent positive charge would be an effective glycosidase inhibitor.

  • Synthesis and conformational analysis of bicyclic Sulfonium salts. Structures related to the glycosidase inhibitor australine.
    The Journal of Organic Chemistry, 2006
    Co-Authors: Nag S. Kumar, B. Mario Pinto
    Abstract:

    The syntheses of eight Sulfonium compounds with structures related to the naturally occurring pyrrolizidine alkaloid, australine, in which the bridgehead nitrogen atom is replaced by a Sulfonium ion, are described. The synthetic strategy relies on the intramolecular attack of a cyclic thioether across a terminal double bond in the presence of a suitable electrophile. We postulate that these compounds, having a permanent positive charge on the sulfur atom, will mimic the highly unstable oxacarbenium ion transition state in a glycosidase-catalyzed hydrolysis reaction. The conformational preferences of these compounds, based on analysis of 1H−1H vicinal coupling constants and 1D-NOESY data, are attributed to both steric and electrostatic interactions. These compounds will be used in the study of structure−activity relationships with glycosidase enzymes.

Alex R Neale - One of the best experts on this subject based on the ideXlab platform.

  • acyclic and cyclic alkyl and ether functionalised Sulfonium ionic liquids based on the tfsi and fsi anions as potential electrolytes for electrochemical applications
    ChemPhysChem, 2018
    Co-Authors: Sinead Murphy, Alex R Neale, Peter Goodrich, Christopher Hardacre, Johan Jacquemin, Flavien Ivol, Fouad Ghamouss
    Abstract:

    This work provides a study based on acyclic and cyclic Sulfonium ionic liquids (ILs) with alkyl and ether-functionality on the cation paired with the bis{(trifluoromethyl)sulfonyl}imide, [TFSI]- , or the bis(fluorosulfonyl)imide, [FSI]- , as the counter anion. Herein, thermophysical characterisation of nine Sulfonium-based ILs concerning the density, viscosity and conductivity and thermal properties including phase transition behaviour and decomposition temperature is reported. The electrochemical stability of the ILs was also measured by cyclic voltammetry at a glassy carbon macro-disk electrode. All of the ILs showed low melting point, low viscosity and good conductivity and could serve as potential electrolytes for energy storage devices.

  • an ether functionalised cyclic Sulfonium based ionic liquid as an electrolyte for electrochemical double layer capacitors
    Journal of Power Sources, 2016
    Co-Authors: Alex R Neale, Andrea Balducci, Stefano Passerini, Christoph Schutter, Peter Goodrich, Christopher Hardacre, Sinead Murphy, Johan Jacquemin
    Abstract:

    A novel cyclic Sulfonium cation-based ionic liquid (IL) with an ether-group appendage and the bis{(trifluoromethyl)sulfonyl}imide anion was synthesised and developed for electrochemical double layer capacitor (EDLC) testing. The synthesis and chemical-physical characterisation of the ether-group containing IL is reported in parallel with a similarly sized alkyl-functionalised Sulfonium IL. Results of the chemical-physical measurements demonstrate how important transport properties, i.e. viscosity and conductivity, can be promoted through the introduction of the ether-functionality without impeding thermal, chemical or electrochemical stability of the IL. Although the apparent transport properties are improved relative to the alkyl-functionalised analogue, the ether-functionalised Sulfonium cation-based IL exhibits moderately high viscosity, and poorer conductivity, when compared to traditional EDLC electrolytes based on organic solvents (propylene carbonate and acetonitrile). Electrochemical testing of the ether-functionalised Sulfonium IL was conducted using activated carbon composite electrodes to inspect the performance of the IL as a solvent-free electrolyte for EDLC application. Good cycling stability was achieved over the studied range and the performance was comparable to other solvent-free, IL-based EDLC systems. Nevertheless, limitations of the attainable performance are primarily the result of sluggish transport properties and a restricted operative voltage of the IL, thus highlighting key aspects of this field which require further attention.

Christopher Hardacre - One of the best experts on this subject based on the ideXlab platform.

  • acyclic and cyclic alkyl and ether functionalised Sulfonium ionic liquids based on the tfsi and fsi anions as potential electrolytes for electrochemical applications
    ChemPhysChem, 2018
    Co-Authors: Sinead Murphy, Alex R Neale, Peter Goodrich, Christopher Hardacre, Johan Jacquemin, Flavien Ivol, Fouad Ghamouss
    Abstract:

    This work provides a study based on acyclic and cyclic Sulfonium ionic liquids (ILs) with alkyl and ether-functionality on the cation paired with the bis{(trifluoromethyl)sulfonyl}imide, [TFSI]- , or the bis(fluorosulfonyl)imide, [FSI]- , as the counter anion. Herein, thermophysical characterisation of nine Sulfonium-based ILs concerning the density, viscosity and conductivity and thermal properties including phase transition behaviour and decomposition temperature is reported. The electrochemical stability of the ILs was also measured by cyclic voltammetry at a glassy carbon macro-disk electrode. All of the ILs showed low melting point, low viscosity and good conductivity and could serve as potential electrolytes for energy storage devices.

  • an ether functionalised cyclic Sulfonium based ionic liquid as an electrolyte for electrochemical double layer capacitors
    Journal of Power Sources, 2016
    Co-Authors: Alex R Neale, Andrea Balducci, Stefano Passerini, Christoph Schutter, Peter Goodrich, Christopher Hardacre, Sinead Murphy, Johan Jacquemin
    Abstract:

    A novel cyclic Sulfonium cation-based ionic liquid (IL) with an ether-group appendage and the bis{(trifluoromethyl)sulfonyl}imide anion was synthesised and developed for electrochemical double layer capacitor (EDLC) testing. The synthesis and chemical-physical characterisation of the ether-group containing IL is reported in parallel with a similarly sized alkyl-functionalised Sulfonium IL. Results of the chemical-physical measurements demonstrate how important transport properties, i.e. viscosity and conductivity, can be promoted through the introduction of the ether-functionality without impeding thermal, chemical or electrochemical stability of the IL. Although the apparent transport properties are improved relative to the alkyl-functionalised analogue, the ether-functionalised Sulfonium cation-based IL exhibits moderately high viscosity, and poorer conductivity, when compared to traditional EDLC electrolytes based on organic solvents (propylene carbonate and acetonitrile). Electrochemical testing of the ether-functionalised Sulfonium IL was conducted using activated carbon composite electrodes to inspect the performance of the IL as a solvent-free electrolyte for EDLC application. Good cycling stability was achieved over the studied range and the performance was comparable to other solvent-free, IL-based EDLC systems. Nevertheless, limitations of the attainable performance are primarily the result of sluggish transport properties and a restricted operative voltage of the IL, thus highlighting key aspects of this field which require further attention.