N. Funasaki et S. Neya, Multiple complexation of didecyldimethylammonium bromide and cyclodextrinsdeduced from electromotive force measurements, LANGMUIR, 16(12), 2000, pp. 5343-5346
The 1:1 and 1:2 macroscopic binding constants of didecyldimethylammonium br
omide (DDAB) and alpha-, beta-, and gamma-cyclodextrins (CD) are determined
from the electromotive force measurements with a DDAB-selective electrode,
and the magnitude of these constants is interpreted in terms of the molecu
lar structures of complexes. The 1:1 macroscopic binding constants of a dou
ble chain surfactant is 2-fold larger than that of a single chain, because
the former has two chains. The 1:1 macroscopic binding constants of DDAB ar
e in the increasing order alpha-CD < beta-CD approximate to alpha-CD, consi
stent with those of a single chain surfactant. In the 1:1 complex of DDAB a
nd gamma-CD, one or two decyl chains are incorporated into the CD cavity. T
he 1:2 macroscopic binding constants of DDAB are in increasing order gamma-
CD << beta-CD alpha-CD. This order is interpreted in terms of the structure
of complexes: the first larger ligated CD inhibits the second ligation mor
e strongly. The present result serves for the quantitative understanding of
the interaction between membrane phospholipid and CD as well as the struct
ure-complexation relationship.