STUDY OF INCLUSION COMPLEX FORMATION OF SUBSTITUTED CYCLODEXTRINS WITH XYLENE ISOMERS

摘要

6-O-α-D-glucosyl-α-cyclodextrin (CD) showed high selectivity in forming an inclusion complex with p-xylene. On the other hand, 2,6-di-O-methyl-α-CD and 6-O-maltosyl-β-CD did not show such selectivity. It corresponded to the values of the formation constants of inclusion complexes determined on the basis of fluorescence measurements. 6-O-α-D-glucosyl-α-CD was supposed to form mainly the 2:1 (CD: p-xylene) inclusion complex, while the latter CDs form the 1:1 inclusion complex. The value of the formation constant of 6-O-α-D-glucosyl-α-CD-p-xylene complex was greater than those of the CD-other xylene isomer complexes. The values of the formation constants of 2,6-di-O-methyl-α-CD-p-xylene complex and 6-O-maltosyl-β-CD-p-xylene complex were not very large compared to those of the CD-other xylene isomer complexes. The high selectivity in the inclusion of p-xylene by 6-O-α-D-glucosyl-α-CD seems to be attributable to the formation of the 2:1 inclusion complex.