Thermodynamic study of the complexation of p-Isopropylcalix[6]arene with Cs+ cation in dimethylsulfoxide-acetonitrile binary media.

• Main Authors: Ahmadzadeh, Saeid, Kassim , Anuar, Rezayi, Majid, Rounaghi, Gholam Hossein
• Format: Article
• Language: English; English
• Published: MDPI 2011
• Online Access: http://psasir.upm.edu.my/id/eprint/24961/1/Thermodynamic%20study%20of%20the%20complexation%20of%20p.pdf; http://psasir.upm.edu.my/id/eprint/24961/; http://www.mdpi.com/

The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide-acetonitrile (DMSO-AN) binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs)+ complex in all binary mixed solvents is 1:1. The stability of the complexes is affected by the composition of the binary solvent media and a non-linear behavior was observed for changes of log K(f) of the complex versus the composition of the binary mixed solvents. The thermodynamic parameters (DH°(c) and DS°(c)) for formation of (p-isopropyl-calix[6]arene·Cs)+ complex were obtained from temperature dependence of the stability constant and the obtained results show that the (p-isopropylcalix[6]arene·Cs)+ complex is enthalpy destabilized, but entropy stabilized, and the values of the mentioned parameters are affected strongly by the nature and composition of the binary mixed solvents.