AMPHIPHILIC 6-S-ALKYL-6-THIOCYCLODEXTRINS - UNIMOLECULAR MICELLAR ANDREVERSE MICELLAR BEHAVIOR

Micellar behaviour of the amphiphilic 6-S-alkyl-6-thiocyclomaltooligos accharid (2) in chloroform has been measured by use of the fluorescent probe 8-anilinonaphthalene-1-sulfonate (ANS) as guest molecule, as we ll as by water-chloroform interfacial tension measurements. At low con centrations the amphiphiles show behaviour consistent with their being oligomers of monosaccharide amphiphiles, or 'unimolecular micelles'. Thus, with ANS, 1:1 complexes are formed for which the association con stants are in proportion to the length of the chains. At higher concen trations, the long-chained (C-16, C-18) alkylthioeyclodextrins form in verted micellar aggregates. The NMR shift changes associated with incl usion of 1-naphthol indicate that even in these aggregates, the carboh ydrate cavity plays a part in complexation, while the hydrophobic chai ns act as extensions of the more hydrophobic primary-hydroxy side of t he cavity.