A Quinoline Based bis-Urea Receptor for Anions: A Selective Receptor for Hydrogen Sulfate

摘要

A dipodal bis-urea receptor has been synthesized from the reaction of 8-amino quinoline and 1,4-phenylene diisocyanate in dichloromethane, and the anion binding ability of the receptor has been studied using fluoride, chloride, bromide, iodide, perchlorate, nitrate, dihydrogen phosphate and hydrogen sulfate by UV-Vis titrations in DMSO. The results show that the receptor binds each of the anions with a 1:1 stoichiometry, showing high affinity, and moderate selectivity for hydrogen sulfate among the anions studied. Ab initio calculations based on density functional theory (DFT) suggest that an anion (X⁻) is bonded within the cleft formed by the two arms of the receptor through two NH…X⁻ and two aromatic CH…X⁻ interactions. The results from solution and theoretical studies suggest that binding is predominately influenced by hydrogen bonding interactions and the basicity of anions.