Synthesis of Fluorescent Molecular Sensory System for Endocrine Disruptors Based on Dansylthiacalix[6]arenes

Abstract

Flexible fluorescent hosts, mono-, di- and tridansyl-modified tert-butylthiacalix[6]arenes (TC[6]A-1, TC[6]A-2 and TC[6]A-3, respectively) and didansyl-tert-butylcalix[6]arene (C[6]A-2) have been synthesized in order to investigate their fluorescent chemosensor functionality, which detects endocrine disruptors. The hosts, TC[6]A-1, TC[6]A-2, TC[6]A-3 and C[6]A-2 exhibit pure monomer fluorescence spectra, of which the spectra shows a decrease fluorescence intensity in the presence of guests. The extent of fluorescence variation of TC[6]A-1, TC[6]A-2, TC[6]A-3 and C[6]A-2 upon a guest addition was recognized as the manifestation of sensing ability of the hosts. A sensing parameter (∆I/I0) was used to describe the sensing ability of four hosts. Host TC[6]A-2 was able to detect 2,4-dichlorophenoxyacetic acid with high sensitivity. The guest-induced variations in the fluorescence intensities and MM2-minimized structures of the hosts suggest that the appended moieties of the hosts act as a hydrophobic cap and a probe showing the host to form a 1:1 host- guest complex.