Advanced

The effect of the head-group spacer length of 12-s-12 gemini surfactants in the host-guest association with beta-cyclodextrin

Carvalho, R. A.; Correia, H. A.; Valente, A. J. M.; Söderman, Olle LU and Nilsson, Markus LU (2011) In Journal of Colloid and Interface Science 354(2). p.725-732
Abstract
NMR spectroscopy has been used to study and characterize the interactions in solution between beta-CD and alkyl-alpha,omega-bis(dodecyldimethyl ammonium bromide) gemini surfactants with the following head-group spacer lengths: 2, 4, 6, 8, and 10. The application of the method of continuous variation gives as a result that 1:1 and 2:1 (beta-cyclodextrin-gemini) complexes are formed; the association stoichiometry is dependent on the spacer chain length, varying from 1.5 (for s = 2) to 1.8 (for s = 10). Assuming a two-step mechanism, the binding constants have been computed. In general, the overall binding constant slightly increases with an increase of the number of methylene groups in the spacer. The H-1 NMR spectra of the N-(CH3)(2) groups... (More)
NMR spectroscopy has been used to study and characterize the interactions in solution between beta-CD and alkyl-alpha,omega-bis(dodecyldimethyl ammonium bromide) gemini surfactants with the following head-group spacer lengths: 2, 4, 6, 8, and 10. The application of the method of continuous variation gives as a result that 1:1 and 2:1 (beta-cyclodextrin-gemini) complexes are formed; the association stoichiometry is dependent on the spacer chain length, varying from 1.5 (for s = 2) to 1.8 (for s = 10). Assuming a two-step mechanism, the binding constants have been computed. In general, the overall binding constant slightly increases with an increase of the number of methylene groups in the spacer. The H-1 NMR spectra of the N-(CH3)(2) groups in beta-cyclodextrin/gemini mixed solutions are split into two peaks for 12-10-12, suggesting that the gemini spacer can thread the beta-cyclodextrin so that the latter is positioned between the gemini head-groups. Inspection of the ROESY spectra allowed the establishment of several spatial proximities between the protons from the beta-CD and the gemini and for a spacer length of 10, the data indeed indicate that complexes are formed with the CD molecule positioned between the two charged head groups with the spacer passing through the CD molecule. (C) 2010 Elsevier Inc. All rights reserved. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Binding constants, structures, Supramolecular, H-1 NMR spectroscopy, Cyclodextrins, Gemini surfactants
in
Journal of Colloid and Interface Science
volume
354
issue
2
pages
725 - 732
publisher
Elsevier
external identifiers
  • wos:000286157000040
  • scopus:78650694503
ISSN
1095-7103
DOI
10.1016/j.jcis.2010.11.024
language
English
LU publication?
yes
id
0d1dfcff-e368-4236-a1b4-eb463b6682a1 (old id 1811422)
date added to LUP
2011-03-16 14:55:58
date last changed
2017-08-20 03:16:27
@article{0d1dfcff-e368-4236-a1b4-eb463b6682a1,
  abstract     = {NMR spectroscopy has been used to study and characterize the interactions in solution between beta-CD and alkyl-alpha,omega-bis(dodecyldimethyl ammonium bromide) gemini surfactants with the following head-group spacer lengths: 2, 4, 6, 8, and 10. The application of the method of continuous variation gives as a result that 1:1 and 2:1 (beta-cyclodextrin-gemini) complexes are formed; the association stoichiometry is dependent on the spacer chain length, varying from 1.5 (for s = 2) to 1.8 (for s = 10). Assuming a two-step mechanism, the binding constants have been computed. In general, the overall binding constant slightly increases with an increase of the number of methylene groups in the spacer. The H-1 NMR spectra of the N-(CH3)(2) groups in beta-cyclodextrin/gemini mixed solutions are split into two peaks for 12-10-12, suggesting that the gemini spacer can thread the beta-cyclodextrin so that the latter is positioned between the gemini head-groups. Inspection of the ROESY spectra allowed the establishment of several spatial proximities between the protons from the beta-CD and the gemini and for a spacer length of 10, the data indeed indicate that complexes are formed with the CD molecule positioned between the two charged head groups with the spacer passing through the CD molecule. (C) 2010 Elsevier Inc. All rights reserved.},
  author       = {Carvalho, R. A. and Correia, H. A. and Valente, A. J. M. and Söderman, Olle and Nilsson, Markus},
  issn         = {1095-7103},
  keyword      = {Binding constants,structures,Supramolecular,H-1 NMR spectroscopy,Cyclodextrins,Gemini surfactants},
  language     = {eng},
  number       = {2},
  pages        = {725--732},
  publisher    = {Elsevier},
  series       = {Journal of Colloid and Interface Science},
  title        = {The effect of the head-group spacer length of 12-s-12 gemini surfactants in the host-guest association with beta-cyclodextrin},
  url          = {http://dx.doi.org/10.1016/j.jcis.2010.11.024},
  volume       = {354},
  year         = {2011},
}