Binding Modes of Nonspherical Anions to N‑Alkylammonium Resorcinarenes in the Solid State

A series of hydrogen bond stabilized N-alkylammonium resorcinarene salts with nitrate, triflate, and picrate as the counteranions were synthesized and characterized with ¹H NMR and electrospray ionization (ESI) mass spectrometry. Together with electrostatic interactions, the binding of the anions with several hydrogen bond donor sites proceeds through a complex array of intra- and intermolecular hydrogen bonds, evidenced by single crystal X-ray diffraction analysis. These N-alkyl ammonium resorcinarenes bind the larger nonspherical anions into deformed cavitand-like structures and enforce a transformation of the resorcinarene conformation from almost symmetrical to extremely distorted.