(R)-N-(Ferrocenylmethyl)-1-hydroxy-3-phenylpropan-2-aminium (E)-but-2-enoate

The crystal structure of the title salt, [Fe(C5H5)(C15H19NO)](C4H5O2), consists of discrete ammonium and carboxylate ions, which associate into infinite chains parallel to [100] by means of N—H...O and O—H...O interactions. These chains are further cross-linked into a three-dimensional network by additional C—H...O contacts and by offset π–π stacking interactions of inversion-related aromatic rings [centroid–centroid distance = 3.7040 (14) Å]. The molecular parameters of the ionic components are in no way unexpected, the geometry of the ammonium cation being similar to that found in other structurally characterized salts obtained from N-ferrocenylmethyl β-aminoalcohols. The (E)-but-2-enoate anion consists of two approximately planar subunits, viz the delocalized carboxylate unit and the butenyl group (the latter being planar within ca. 0.002 Å), which are mutually rotated by 30.3 (4)°