Issue 12, 1999

Electrochemical behaviour of new electroreducible amphiphilic saccharide derivatives II: Electroreduction in protic media

Abstract

The electrochemical reduction of new amphiphilic molecules derived from sugars and aromatic ketones has been performed in protic media under basic and acidic conditions. Exhaustive electrolyses have yielded, regardless of pH, the alcohol resulting from two-electron and two-proton exchanges. No trace of pinacol was detected. This unusual behaviour has been related to the properties of the saccharidic moiety, which can favour a highly hindered bent back conformation. The dimerisation reaction is thus less probable. Molecular calculations and a dynamic study in aqueous solution have shown that the less energetic conformations are stabilised by hydrogen bonds between the sugar moiety and the carbonyl group by means of six water molecules, three of them building a solvation chain between the carbonyl function and the primary alcohol of the sugar. As a comparison the same calculations, applied to an aprotic solvent (DMF), indicate an extended form for the conformation of lowest energy. Re′duction e′lectrochimique de nouvelles mole′cules amphiphiles de′rive′es de sucres. Partie II : Etude en milieu protique. En milieu protique, la re′duction e′lectrochimique de nouvelles mole′cules amphiphiles de′rive′es de sucres et de ce′tones aromatiques a e′te′ re′alise′e en milieu basique et acide. Les e′lectrolyses exhaustives ont permis d'isoler, quel que soit le pH, l'alcool re′sultant du transfert de deux e′lectrons et de deux protons. Aucune trace de pinacols n'a e′te′ de′cele′e. Ce comportement inhabituel a e′te′ relie′ aux proprie′te′s du sucre pre′sent dans la mole′cule. L'e′tablissement de liaisons hydrogène avec la fonction carbonyle par l'interme′diaire de mole′cules d'eau entraîne une conformation globulaire très encombre′e qui peut de′favoriser la re′action de dime′risation. Des calculs de dynamique mole′culaire ont montre′ que les conformations de plus faible e′nergie correspondent à une forme replie′e faisant intervenir six mole′cules d'eau dont trois constituent une chaîne de solvatation maintenant l'ensemble par liaisons hydrogène. Dans un solvant aprotique (DMF), les mêmes calculs conduisent à une forme de′ploye′e pour la mole′cule amphiphile.

Article information

Article type
Paper

New J. Chem., 1999,23, 1171-1175

Electrochemical behaviour of new electroreducible amphiphilic saccharide derivatives II: Electroreduction in protic media

C. Maurice, B. Schöllhorn, B. Aboab, G. Mousset and C. Mousty, New J. Chem., 1999, 23, 1171 DOI: 10.1039/A906282C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements