Open AccessThermodynamics of Complexation between Thiourea-based Receptor and Acetate in Water/Acetonitrile Mixture
Author(s) -
Takakazu Suzuki,
Yotsugi Shibuya,
Tokijiro Sato,
Seiichi Nishizawa,
Itaru Sato,
A. Yamaguchi
Publication year - 2016
Publication title -
analytical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 73
eISSN - 1348-2246
pISSN - 0910-6340
DOI - 10.2116/analsci.32.741
Subject(s) - chemistry , acetonitrile , thiourea , thermodynamics , inorganic chemistry , chromatography , organic chemistry , physics
A thiourea-based receptor has been extensively studied for selective anion recognition for reasons of its strong hydrogen bond donor ability. In the present study, the thermodynamics of complexation between a thiourea-based receptor and acetate was examined in a water/acetonitrile mixture. The receptor used in this study was N,N'-bis(p-nitrophenyl)thiourea (BNPTU). UV/vis spectroscopic titration and isothermal titration calorimetry (ITC) experiments clearly revealed endothermic and entropy-driven complexation of BNPTU with acetate in water/acetonitrile mixtures. Since the endothermic peaks found in water/acetonitrile mixtures were about three times greater than those in acetonitrile, it appears that preferential hydration of both receptor and acetate was responsible for the endothermic and entropy-driven complexation reaction. The thermodynamic properties found in this study have the potential to contribute to the design of a thiourea-based anion receptor.