Benzene-based tripodal isothiouronium compounds as sulfate ion receptors

• DOI: 10.1016/j.tetlet.2003.11.048
• Publication Date: 2003-12-09T11:55:53Z
• Authors: Hye Ran Seong; Dae-Sik Kim; Sung-Gon Kim; Heung-Jin Choi; Kyo Han Ahn
• Keywords: CHIRAL MOLECULAR RECOGNITION; sulfate recognition; HOST; OXAZOLINE RECEPTORS; COMPLEXATION; preorganization; ANION RECEPTOR; GUANIDINIUM; thiouronium compounds; anion recognition; 01 natural sciences; AQUEOUS-SOLUTION; TRANSPORT; 0104 chemical sciences; ARTIFICIAL RECEPTORS; SELECTIVE ELECTRODE; THIOUREA GROUPS; BINDING; tripodal receptors; PHOSPHATE; CHEMOSENSOR

Novel benzene-based tripodal isothiouronium receptors are synthesized for the selective recognition of tetrahedral oxoanions. The binding study by isothermal titration calorimetry indicates that the cationic receptors bind sulfate ions preferably in a tripodal mode, while they show a mixed binding mode toward phosphate ion. The tripodal isothiouronium receptors show large ΔG0 values toward sulfate ions in methanol, which are entropy driven. The results demonstrate that a subtle structural constraint can lead to different binding modes toward structurally similar anions.