Molecular structure of the 1:2 complex of 2-quinuclidinium-butyrate with p-hydroxybenzoic acid

► 2-Quinuclidinium butyrate forms with two p-hydroxybenzoic acids two H-bonded rings. ► According to DFT calculations the dimer 3 is more stable than monomer 2. ► Stretching vibrations of the carboxylic and carboxylate groups appear in the IR spectrum. ► The methylene protons in the ethyl group are non-equivalent in the NMR spectrum.