A quinoline based bis-urea receptor for anions: a selective receptor for hydrogen sulfate.

Tiffany H Russ, Avijit Pramanik, Maryam E Khansari, Bryan M Wong, Md Alamgir Hossain

Index: Nat. Prod. Commun. 7(3) , 301-4, (2012)

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Abstract

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 predominantly influenced by hydrogen bonding interactions and the basicity of anions.