Efficient synthesis and anion recognition of a colorimetric preorganized tripodal thiourea compound

A preorganized colorimetric tripodal thiourea receptor was synthesized in high yield utilizing a thiol-ene reaction as a primary step. The interaction of the receptor with dihydrogen phosphate, acetate, chloride, and fluoride anions was investigated using UV–vis. and 1H NMR spectroscopic titration techniques. The binding stoichiometry of the receptor with dihydrogen phosphate and acetate was found to be 1:2, and 1:1 with chloride and fluoride. The binding constants for the receptor and dihydrogen phosphate, acetate, chloride, and fluoride were determined using HypNMR2008 and HypSpec.