NMR diffusometry and conductometry study of the host-guest association between beta-cyclodextrin and dodecane 1,12-bis(trimethylammonium bromide).
Surfactants form association complexes with cyclodextrins. In the present investigation we have used NMR-diffusometry and electrical conductivity to follow the interactions which take place between beta-cyclodextrin and a bolaform surfactant: dodecane 1,12-bis(trimethylammonium bromide). Both (1)H NMR self-diffusion and conductometry data indicate the formation of a 1:1 inclusion complex. Assuming this stoichiometry, it was possible to calculate the association constant; from the analysis of the self-diffusion coefficients of free beta-cyclodextrin and the bolaform surfactant an association constant K=3x10(3)M(-1) was obtained while the analysis of conductivity data gave a comparable value of K=2.5x10(3)M(-1).
Cabaleiro-Lago
Celia
C
Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE 221 00 Lund, Sweden. celiacl@uvigo.es
Nilsson
Markus
M
Valente
Artur J M
AJ
Bonini
Massimo
M
Söderman
Olle
O