title: Anion binding in aqueous solutions by N-(Isonicotinamido)-N'-phenylthiourea-based simple synthetic neutral receptors. role of the hydrophobic microenvironment of the receptor molecule.
abstract: N-(Isonicotinamido)-N'-(substituted-phenyl)thioureas (1a-e, substituent X = p-OCH3, p-CH3, H, m-Br, and m-CF3) have been designed as neutral receptors, in order to prove the influence of conformational issues on the ability to bind anions in aqueous solutions. Compounds 1a-e were shown to create a hydrophobic microenvironment around the thiourea group, favoring hydrogen bonding interactions, by evidence from quantum mechanic calculations, thermodynamic analysis, NMR aromatic current shielding, and comparative anion binding. Referring to N-(substituted-benzamido)thioureas (2a-e, substituent Y = H, m-Cl, m-NO2, m,m-Cl,Cl, and p-NO2), we showed that, for the hydrophobic microenvironment to be operative in aqueous solutions, the amido -NH proton needs to be acidic enough.
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, and The MOE Key Laboratory of Analytical Sciences, Xiamen University, Xiamen 361005, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Yang
authors.forename: Wen-Xia
authors.initials: WX
authors.lastname: Liu
authors.forename: Hong
authors.initials: H
authors.lastname: Shen
authors.forename: Hui-Hui
authors.initials: HH
authors.lastname: Huang
authors.forename: Yun-Bao
authors.initials: YB
authors.lastname: Jiang