Physicochemical properties of ammonium-based deep eutectic solvents and their electrochemical evaluation using organometallic reference redox systems

Laleh Bahadori, Mohammed Harun Chakrabarti, Farouq Sabri Mjalli, Inas Muen Alnashef, Ninie Suhana Abdul Manan, Mohd Ali Hashim

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37 Citations (Scopus)


Seven deep eutectic solvents (DESs) containing ammonium based salts are prepared by means of hydrogen bonding with acid, amine, amide and nitrate based compounds. The major physicochemical properties of the DESs in terms of density, viscosity, electrical conductivity, molar conductivity and pH are investigated prior to ascertaining their electrochemical characteristics by means of cyclic voltammetry and chronoamperometry. Nitrate based DESs exhibit higher conductivities but lower viscosities than other DESs, whereas the amide based DES displays the widest electrochemical potential window. Diffusion coefficient, D, of two organometallic redox couples, Fc/Fc+ (ferrocene/ ferrocenium) and Cc/Cc+(cobaltocene/cobaltocenium) is found to be of the order of 10-9 to 10-8 cm2 s-1 in all studied DESs while the heterogeneous rate constant for electron transfer across the electrode/DES interface is of the order of 10-4 cm s -1. The Stokes-Einstein products of Fc and Cc+ in the DESs have also been determined.

Original languageEnglish
Pages (from-to)205-211
Number of pages7
JournalElectrochimica Acta
Publication statusPublished - 2013



  • Deep eutectic solvents
  • Electrochemical window
  • Organometallic reference redox systems
  • Stokes-Einstein product
  • Walden plot of DESs

ASJC Scopus subject areas

  • Electrochemistry
  • Chemical Engineering(all)

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