Centrosymmetric and Noncentrosymmetric <i>R</i>⁴₄(12) Rings As Primary Motifs in Salts of Sulfonate Anions and Chiral Primary Ammonium Cations: Their Occurrence in Hydrates, Nonhydrates, and the Zöllner Illusion

The acid−base reaction of naphthalene-1,5-disulfonic acid and naphthalene-2-sulfonic acid with homochiral (R)-1-phenylethylamine or (S)-1-phenylethylamine or heterochiral (RS)-1-phenethylamine give rise to 9 new organic salts: ((R)-1-phenylethylammonium)2•(naphthalene-1,5-disulfonate)•(H2O)2 (2), ((S)-1-phenylethylammonium)2•(naphthalene-1,5-disulfonate)•(H2O)2 (3), ((RS)-1-phenylethylammonium)2•(naphthalene-1,5-disulfonate)•(H2O)2 (4), ((R)-1-phenylethylammonium)2•(naphthalene-1,5-disulfonate) (5), ((S)-1-phenylethylammonium)2•(naphthalene-1,5-disulfonate) (6) ((RS)-1-phenylethylammonium)2•(naphthalene-1,5-disulfonate) (7), ((R)-1-phenylethylammonium)•(naphthalene-2-sulfonate) (8), ((S)-1-phenylethylammonium)•(naphthalene-2-sulfonate) (9) and ((RS)-1-phenylethylammonium)•(naphthalene-2-sulfonate) (10). All nine ammonium sulfonate salts have different 1-D hydrogen bonded columns, some containing water molecules (2−4), which are made up of different sequences of hydrogen bonded rings. The most common hydrogen bonded ring formed by the ammonium and sulfonate ions has graph set notation R44(12). Structures 2−7 have the columns linked to form 2-D hydrogen bonded sheets and 8−10 have simple 1-D chains. The results of this work as well as an analysis of the Cambridge Structural Database indicate that the R44(12) is a dominant motif in crystals composed of ammonium sulfonate salts in the same way that R22(8) is the dominant motif in carboxylic acids.