ABSORPTIOMETRIC AND SPECTROFLUOROMETRIC STUDY OF THE INCLUSION COMPLEXES OF 2-NAPHTHYLOXYACETIC ACID AND 1-NAPHTHYLACETIC ACID WITH BETA-CYCLODEXTRIN IN AQUEOUS-SOLUTION

The inclusion complexes of 2-naphthyloxyacetic acid (NOA) and 1-naphth ylacetic acid (NAA) with beta-cyclodextrin have been investigated in a queous solution. It has been demonstrated that the naphthalene derivat ives form 1 : 1 complexes when included in the cyclodextrin. A possibl e structure is proposed, having an axial inclusion of the naphthalene derivatives. In the case of the beta-CD: NOA complex, the naphthyl moi ety is included in the cyclodextrin and the acetic acid group protrude s from the cavity, while NAA is only partially included because of the steric effect of the group in position 1. Association constants of 56 0 +/- 100 M-1 and 100 +/- 50 M-1 have been calculated for the beta-CD : NOA and beta-CD : NAA complexes, making use of the increment in the fluorescene emission produced in the inclusion process.