Complexation of a disulfide-linked α-cyclodextrin dimer with 1-alkanols

NMR titration experiments showed that a disulfide-linked α-cyclodextrin dimer (1) stepwise forms 1:1 and 1:2 (host:guest) complexes with 1-alkanols. In the cases of ethanol and 1-propanol with short alkyl chains, the first and second guest molecules are included within the different CD cavities of 1. On the other hand, 1-pentanol and 1-hexanol with relatively long alkyl chains are bound to both of the CD cavities of 1 in their 1:1 complexes. The 1:1 complexes are less soluble in D2O than their 1:2 complexes and slowly form precipitates.