A series of molecular complexes of the proton sponge 1,8-bis(dimethylamino)naphthalene (DMAN) with monosubstituted halobenzoic acids are reported, illustrating the designed exploitation of the characteristics of the proton sponge to induce short, charge-assisted hydrogen bonds in a predictable and reproducible manner. In every case, a DMAN molecule extracts a proton from the carboxylic acid group of the benzoic acid, as a result of which a recurrent supramolecular unit between a neutral and a deprotonated benzoic acid molecule is formed, featuring an extremely short, strong O–H···O hydrogen bond, within a predominant crystallization ratio of 1:2 (DMAN:benzoic acid).
Thomas, L. H., Jones, A. O. F., Kallay, A. A., McIntyre, G. J., & Wilson, C. C. (2016). Engineering Short, Strong, Charge-Assisted Hydrogen Bonds in Benzoic Acid Dimers through Cocrystallization with Proton Sponge. Crystal growth & design, 16(4), 2112-2122. https://doi.org/10.1021/acs.cgd.5b01787