HOST GUEST SENSORS OF 6(A),6(B)-BIS(2-NAPHTHYLSULFENYL)-GAMMA-CYCLODEXTRINS, 6(A),6(C)-BIS(2-NAPHTHYLSULFENYL)-GAMMA-CYCLODEXTRINS, 6(A),6(D)-BIS(2-NAPHTHYLSULFENYL)-GAMMA-CYCLODEXTRINS, AND 6(A),6(E)-BIS(2-NAPHTHYLSULFENYL)-GAMMA-CYCLODEXTRINS FOR DETECTING ORGANIC-COMPOUNDS BY FLUORESCENCE ENHANCEMENT

Gamma-cyclodextrin derivatives 1-4 which have two naphthyl moleties at AB, AC, AD, and AE glucose residues, respectively, have been prepared as a series of sensors for detecting organic compounds. They exhibit almost pure monomer fluorescence whose intensity is enhanced upon addition of guest species. The value Im/Im-degrees, where Im and Im-degrees are fluorescence intensities in the presence and absence of a guest, was used as a sensitivity parameter. The data for twelve organic compounds were collected. Four steroidal compounds such as cholic acid (5), deoxycholic acid (6), chenodeoxycholic acid (7), and ursodeoxycholic acid (8) were detected by 1, 2, and 3 with the order of the sensitivity 5 < 6 < 7 < 8 while they were detected by 4 with the order 8 < 5 < 7 < 6. Three alcohols such as l-borneol (9), cyclohexanol (10), and cyclododecanol (12) were detected by 1-4 with the order of the sensitivity 10 < 9 < 12. 1-Adamantanecarboxylic acid (11) exhibits sensitivities comparable to those of bicyclic compound 9. Nerol (13), geraniol (14), d-menthol (15), and l-menthol (16) were detected with much smaller sensitivities than 9, and geometrical and chiral discrimination for them was not appreciable. Binding constants of 1-4 for 5, 9, 11, and 12 were obtained. Among four hosts, 2 gave the largest binding constant for each of the guests. The binding constants of 2 for the guests are in the order 9 < 11 < 5 < 12 and roughly parallel with the sensitivity parameters.