Spectrofluorimetric Study of Cyclodextrin Complexation in the Presence of Third and Fourth Components

Abstract

The steady-state fluorescence profile of 4,5-benzopiaselenol (Se-DAN) has been investigatedin mixed aqueous media comprising cyclodextrins (CDs) andsodium dodecyl sulfate (SDS).The emission intensity of Se-DAN, whereas virtually unaffected in the αCD/SDS medium, wasenhanced synergistically by βCD and SDS and was accompanied by a marked blue shift of themaximum emission wavelength. The interactions involving γCD were rather interesting. While amixed solution of γCD and SDS brought about a slight fluorescence increase of Se-DAN, additionof toluene, a fourth component, resulted in a pronounced emission enhancement. To ascertain therole of toluene in the system, a model study was carried out by use of pyrene (Py) as a fluorescenceprobe in place of Se-DAN/SDS. A 1:1:1γCD/Py/toluene ternary complexwas detected and itsassociation constant was determined to be 869 M-1, significantly greater than the previously reportedvalues of the γCD/Py binary complex. On the basis of the mechanisticstudy, the formation of aγCD/Se-DAN/SDS/toluene quaternary complex is proposed.