Investigation of host-guest complexation of the ternary model: p-Sulfonatothiacalix[4]arene-fluorescein-M2+

In comparison to traditional calyx[4]arene, thiacalix[4]arene is unique due to its bridging S-atoms. Therefore, functionalized p-sulfonato thiacalix[4]arene has been used for the detection of some transition metal ions. The inclusion behavior between the important water soluble p-sulfonato thiacalix[4]arene with fluorescein and M2+(Co2+, Ni2+, Cu2+, Zn2+) ions has been studied using a spectrofluorometric method. H-1 NMR, 2D NMR and IR spectra also supported the complexation. The complex stability follows the order Cu2+ >Zn2+> Co2+>Ni2+ , which is supported by the Irving-Williams series. The combined results demonstrate the cooperative interaction of the M2+ ions with p-sulfonato thiacalix[4]arene and this is further supported by a molecular docking study. (C) 2019 Elsevier Ltd. All rights reserved.