Fine-tuning of properties of bismacrocyclic dinuclear cyclidene receptors by N-methylation.

Agnieszka Więckowska 1Renata Bilewicz 1Krzysztof Woźniak 1Jadwiga Szydłowska 1Bohdan Korybut-Daszkiewicz 2

1. Warsaw University, Faculty of Chemistry, Pasteura 1, Warszawa 02-093, Poland
2. Polish Academy of Sciences, Institute of Physical Chemistry, Kasprzaka 44/52, Warszawa 01-224, Poland


By changing properties of components of mechanically bonded molecules, one can variate properties of resulting complex structures. Such a tuning of properties can be achieved by severe measures as, for example, replacement of the metal ions, elongation of the aliphatic linkers or change of macrocycles. On the other hand, more subtle changes of properties can be introduced by proper chemical modifications of particular positions of the parent systems. We present the role of N-methylation in controlling the properties of bismacrocyclic substrates used for the construction of more complex molecules.

N-methylated bismacrocyclic Cu and Ni complexes were synthesized and structurally characterised in the solid state. Their properties in the solution were analysed using NMR, ESR spectroscopies and electrochemical methods. Face-to-face biscyclidenes linked via polymethylene chains form rectangular box-like cations. These moieties can host some small guests molecules (water, p-electron donating compounds) and are stabilised by a shell of neighbouring couterions.

For the bismacrocyclic dinuclear complexes containing two nickel or two copper ions, the intramolecular interactions between the metallic centres are strengthened through methylation of the macrocyclic components comparing to the non-methylated species.

Methylation weakens electron acceptor properties of the complexes leading to less effective binding of the p-electron donating guests. It also increases the stability of the lower oxidation states. In the case of the copper complexes both Cu(II)/Cu(I) and Cu(II)/Cu(III) reversible 1 electron transfers are seen in the voltammograms. These changes in properties are interpreted as consequences of steric repulsion between the methyl substituents and the macrocyclic ring.

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. What modern crystallography can add to pharmaceutical research?
  2. Physicochemical characterization of sunitinib and its impurities
  3. Recent developments in enzymatic biofuel cells
  4. Biofuel cell based on carbon nanotubes with covalently bonded laccase and glucose dehydrogenase embedded in cubic phase
  5. Tetraazamacrocyclic copper(II) and nickel(II) complexes in host - guest systems.
  6. Free-radical adsorption as a method of binding gold nanoparticles to gold electrode surfaces.
  7. Biofuel cell based on arylated carbon nanotubes
  8. Experimental and theoretical charge density studies on a model analogue of vitamin D
  9. Carbon nanotube nanostructured electrodes for membrane – less biofuel cell based on liquid-crystalline phases as matrices for enzymes
  10. Cyclodextrins as molecular recognition elements in monolayers
  11. A glucose/O2 biofuel cell based on electrodes modified with liquid-crystalline cubic phases
  12. Redox processes of dithiolated tetraazamacrocyclic complexes of Ni(II) and Cu(II) in solution and immobilized on gold electrodes
  13. Nanostructured Carbon Electrodes For Oxygen Reduction Catalyzed By Laccase Without any Mediators
  14. Charge Density Studies of Tetraazamacrocyclic Complexes of Copper(II) and Nickel(II)
  15. Sigma Cutoff - and What Lies Behind
  16. Molecular Motions in New Catenanes
  17. New methods of immobilization of oxidases at electrodes
  18. Electron transport through alkanethiolate films decorated with monolayer-protected gold clusters
  19. Designing of cathodes modified with enzymes for the biofuel cell applications
  20. Lipidic cubic phase for immobilising enzymes on electrodes
  21. Electrochemical characteristics and interaction with anions of homo- and heterodinuclear biscyclidene Ni(II) and Cu(II) complexes bridged by two di-aza-18-crown-6 ethers
  22. Properties of monolayers of azocrown ethers: Ph -tunable equilibria for compounds with substituents containing mobile protons
  23. Modified Electrodes Based on Lipidic Cubic Phases

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

Submitted: 2005-08-04 11:44
Revised:   2009-06-07 00:44
© 1998-2021 pielaszek research, all rights reserved Powered by the Conference Engine