Properties of monolayers of azocrown ethers: Ph -tunable equilibria for compounds with substituents containing mobile protons

Elżbieta Jabłonowska 1Barbara Pałys 1Renata Bilewicz 1Ewa Wagner-Wysiecka 2Marzena Jamrógiewicz 2Jan F. Biernat 2

1. Warsaw University, Faculty of Chemistry, Pasteura 1, Warszawa 02-093, Poland
2. Gdańsk University of Technology, Department of Chemical Technology, Narutowicza 11/12, Gdańsk 80-264, Poland


The crown ethers with electro- and photoactive azo moieties containing -OH, or COOH groups show unique effect of pH switched on/off presence of the azo form. It is well known that electrode processes of azocompounds are pH dependent but we show here that they are also strongly influenced by substituents containing mobile protons such as in -COOH groups. Azocrown ether with N-acetyl-histidine moiety in the molecule gave different Raman spectra compared to those of the imidazole azocrown ether, however, only in acidified solutions. . In alkaline medium the spectra were similar.

The differences in the electrochemical reduction of the imidazole and histidine derivatives in strongly acidified solutions reflect the interference of chemical reduction. It is catalyzed by mobile protons of the -COOH group present in the histidine derivative, leading further to the formation of the hydrazine form. Thus, for the N-acetylhistidine azomacrocyle similar behaviour is revealed to that of azophenol compounds which are known to exist in quinone-hydrazone tautomeric equilibria.

Legal notice
  • Legal notice:

    Copyright (c) Pielaszek Research, all rights reserved.
    The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
    In every case, proper references including Author(s) name(s) and URL of this webpage: must be provided.


Related papers
  1. Recent developments in enzymatic biofuel cells
  2. Biofuel cell based on carbon nanotubes with covalently bonded laccase and glucose dehydrogenase embedded in cubic phase
  3. Tetraazamacrocyclic copper(II) and nickel(II) complexes in host - guest systems.
  4. Free-radical adsorption as a method of binding gold nanoparticles to gold electrode surfaces.
  5. Biofuel cell based on arylated carbon nanotubes
  6. Carbon nanotube nanostructured electrodes for membrane – less biofuel cell based on liquid-crystalline phases as matrices for enzymes
  7. Cyclodextrins as molecular recognition elements in monolayers
  8. Poly-o-aminophenol as laccase mediator and influence of enzyme on the polymer electrodeposition
  9.   “Preliminary study of silicone gel sheets containing onion (Allium cepae) extract for treatment of scars”
  10. A glucose/O2 biofuel cell based on electrodes modified with liquid-crystalline cubic phases
  11. Redox processes of dithiolated tetraazamacrocyclic complexes of Ni(II) and Cu(II) in solution and immobilized on gold electrodes
  12. Nanostructured Carbon Electrodes For Oxygen Reduction Catalyzed By Laccase Without any Mediators
  13. Molecular Motions in New Catenanes
  14. New methods of immobilization of oxidases at electrodes
  15. Electron transport through alkanethiolate films decorated with monolayer-protected gold clusters
  16. Fine-tuning of properties of bismacrocyclic dinuclear cyclidene receptors by N-methylation.
  17. Designing of cathodes modified with enzymes for the biofuel cell applications
  18. Lipidic cubic phase for immobilising enzymes on electrodes
  19. Modified Electrodes Based on Lipidic Cubic Phases

Presentation: Poster at SMCBS'2005 Workshop, by Elżbieta Jabłonowska
See On-line Journal of SMCBS'2005 Workshop

Submitted: 2005-07-27 11:48
Revised:   2009-06-07 00:44
© 1998-2021 pielaszek research, all rights reserved Powered by the Conference Engine