Synthesis and Complexive Abilities in Cone Conformation of Lower Rim Functionalized Calix[4]Arene with Alkali Metal Cations

Farrokh Gharib,¹* Maryam Shakarami¹ and Saeed Taghvaei-Ganjali²

¹ Chemistry Department, Shahid Beheshti University, Tehran, Evin, Iran;
² Chemistry Department, I. Azad University, North Tehran Branch, Tehran, Iran
* Corresponding author: E-mail: f-gharib@cc.sbu.ac.ir

Abstract
The synthesis and complexive abilities of 5,11,17,23-tetra-tert-butyl-28,26-di(bromopropoxy)-25,27-dihydroxycalix[ 4]arene (L1) and 5,11,17,23-tetra-tert-butyl-25,27-dibenzoxy-26,28-di(phenoxy)propoxycalix[4]arene (L2) towards alkali metal cations Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺ in methanol-chloroform mixture have been evaluated at 25 C, using UV-Vis spectrophotometric techniques. The results showed that the ligands are capable to complex with all the alkali cations by 1:1 metal to ligand ratios. Considering the formation constant values, the binding selectivities of the ligands towards alkali cations of the formed complexes are in the order Rb⁺ ≈ K⁺ > Cs⁺ > Na⁺ > Li⁺ and Li⁺ > Na⁺ > K⁺ ≈ Rb⁺ ≈ Cs⁺ for the ligands L1 and L2, respectively.

Keywords: calix[4]arene, alkali cations, synthesis, complexation, formation constant