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Interactions between gemini surfactants, 12-s-12, and beta-cyclodextrin as investigated by NMR diffusometry and electric conductometry

Nilsson, Markus ; Cabaleiro-Lago, Celia ; Valente, Artur and Söderman, Olle LU (2006) In Langmuir 22(21). p.8663-8669
Abstract
The interaction between beta-cyclodextrin (CD) and gemini surfactant of the type alkyl-alpha,omega-bis(dodecyldimethyl-ammonium bromide) with different spacer lengths of 2, 8, and 10 carbons has been investigated by means of electric conductivity (EC) and proton self-diffusion NMR at 298 K. The formation of a 2: 1 (CD: gemini) complex in a two-step mechanism is observed with the first association constant (K-11) higher than the second one (K-21), but both relatively small in comparison with single C-12-tailed surfactant. The value of the association constants increased with spacer length both for the first and second associated CD, which indicates that the available space on the gemini molecule is important. The magnitudes of the... (More)
The interaction between beta-cyclodextrin (CD) and gemini surfactant of the type alkyl-alpha,omega-bis(dodecyldimethyl-ammonium bromide) with different spacer lengths of 2, 8, and 10 carbons has been investigated by means of electric conductivity (EC) and proton self-diffusion NMR at 298 K. The formation of a 2: 1 (CD: gemini) complex in a two-step mechanism is observed with the first association constant (K-11) higher than the second one (K-21), but both relatively small in comparison with single C-12-tailed surfactant. The value of the association constants increased with spacer length both for the first and second associated CD, which indicates that the available space on the gemini molecule is important. The magnitudes of the association constant both for the first and second complexation are discussed. The first association constant is small ( when compared with the homologous single-chain surfactant) due to hydrophobic interaction between the hydrocarbon tails within the gemini molecule, while the second association constant shows no cooperativity and its magnitude is discussed in terms of steric constrains. (Less)
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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Langmuir
volume
22
issue
21
pages
8663 - 8669
publisher
The American Chemical Society (ACS)
external identifiers
  • wos:000240954300011
  • scopus:33750345830
ISSN
0743-7463
DOI
10.1021/la061220e
language
English
LU publication?
yes
id
31858d55-eecd-46ec-a77f-f3529a17e263 (old id 389482)
date added to LUP
2016-04-01 11:57:33
date last changed
2021-03-24 03:44:17
@article{31858d55-eecd-46ec-a77f-f3529a17e263,
  abstract     = {The interaction between beta-cyclodextrin (CD) and gemini surfactant of the type alkyl-alpha,omega-bis(dodecyldimethyl-ammonium bromide) with different spacer lengths of 2, 8, and 10 carbons has been investigated by means of electric conductivity (EC) and proton self-diffusion NMR at 298 K. The formation of a 2: 1 (CD: gemini) complex in a two-step mechanism is observed with the first association constant (K-11) higher than the second one (K-21), but both relatively small in comparison with single C-12-tailed surfactant. The value of the association constants increased with spacer length both for the first and second associated CD, which indicates that the available space on the gemini molecule is important. The magnitudes of the association constant both for the first and second complexation are discussed. The first association constant is small ( when compared with the homologous single-chain surfactant) due to hydrophobic interaction between the hydrocarbon tails within the gemini molecule, while the second association constant shows no cooperativity and its magnitude is discussed in terms of steric constrains.},
  author       = {Nilsson, Markus and Cabaleiro-Lago, Celia and Valente, Artur and Söderman, Olle},
  issn         = {0743-7463},
  language     = {eng},
  number       = {21},
  pages        = {8663--8669},
  publisher    = {The American Chemical Society (ACS)},
  series       = {Langmuir},
  title        = {Interactions between gemini surfactants, 12-s-12, and beta-cyclodextrin as investigated by NMR diffusometry and electric conductometry},
  url          = {http://dx.doi.org/10.1021/la061220e},
  doi          = {10.1021/la061220e},
  volume       = {22},
  year         = {2006},
}