A new anion receptor utilising aromatic and aliphatic C…H hydrogen bonds

Abstract

We have synthesised 2, which bound weakly basic halide ions only with C–H…anion hydrogen bonds. Compound 2 utilised one aromatic C–H hydrogen bond and one benzylic C–H hydrogen bond to bind weakly halide ions such as chloride, bromide and iodide in solution. Ab initio calculations of binding energy values for these anions are in good agreement with experimental data. Although the binding affinities of 2 for these anions were low, 2 could be a unique example of host, which utilised only C–H hydrogen bonds to bind anion.