Specific Binding of Primary Ammonium Ions and Lysine-Containing Peptides in Protic Solvents by Hexahomotrioxacalix[3]arenes.

The binding of ammonium ions by two homooxacalix[3]arene-based receptors was studied using NMR spectroscopy and in silico methods. Both receptors are shown to endocomplex, even in a protic environment, a large variety of primary ammonium ions, including biomolecules. The binding mode is similar for all guests with the ammonium ion deeply inserted into the polyaromatic cavity and its NH