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