New Azothiacalix[4]arenes Containing Biheterocyclic Subunits: Extraction and Complexation Properties

Abstract

New thiacalixl4]arenes 2a, 3a, 4 and 5 functionalized with biheterocyclic and azophenyl groups at the lower rim and the upper rim of the macrocycle, respectively, were synthesized and their extraction properties towards Cu^"^, Ag^, Ni-"" and Pb-" studied. The complexation properties of the bithiazolyl receptors 2a, 4 and the bipyridyi receptors 3a, 5 were investigated by fluorescence and UV-visible titrations, respectively. The stoichiometries of the complexes were determined. A stoichiometry of 1:1 was found for the Cu-2a, Ag-3a complexes and 2:1 for the Cu2-4, Ag2-5 complexes as a function of the number of grafted bithiazotyl groups. The association constants for the 1:1 complexes were calculated using the Benesi-Hildebrand plot and by linear regression analysis.

Anion Complexation by an Azocalix[4]arene Derivative and the Scope of Its Fluoride Complex Salt to Capture CO2 from the Air

“…More particularly, azophenol-based chemo-sensors have been widely incorporated into the chromoionophores. These compounds can display a change in their absorption spectra in addition to a colour change upon interaction with metal cations [ 24 , 25 , 26 , 27 , 28 , 29 ] or anions [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ]. A series of non-macrocyclic azophenol derivatives as chromogenic units designed to selectively generate colour change as they complex with different anions has been reported by Hong and co-workers [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ].…”