Supramolecular assemblies of phenyl-pyridyl-triazolopyridine and β-cyclodextrin as sensor of divalent cations in aqueous solution

• Association constant of PhPTP with DMβCD is 5 times higher than βCD.
• Thermodynamic studies indicate that inclusion for both cyclodextrins are entropic driven.
• The structure of inclusion complex is proposed by 2D-ROESY and molecular docking.
• The fluorescence changes indicate a high selectivity and sensitivity for Fe2+.

The chemosensor 3-phenyl-7-(pyrid-2-yl)-[1,2,3]triazolo[1,5-a]pyridine (PhPTP) used in combination with two different cyclodextrins, enable its solubilization and stabilization in aqueous solution. The behavior of the inclusion complex, and its binding ability in both cyclodextrins were investigated by means of absorption and fluorescence spectroscopy. The best results were obtained for PhPTP-DMβCD assembly, and its orientation in the DMβCD nano cavity was obtained by 2D-NMR. This inclusion geometry was confirmed by docking studies. The binary complex was proved as chemosensor upon the presence of different divalent cations in aqueous solutions. The PhPTP-DMβCD system, displays a high sensitivity for Fe2+ by fluorescence quenching in neutral aqueous solution even in the presence of other metals showing high selectivity towards Fe2+.