The title salt, C(8)H(20)N(+)·C(22)H(27)O(3)S(-), is a proton-transfer compound derived from the recently reported parent carb-oxy-lic acid [Alhadi et al. (2010). Acta Cryst. E66, o1787] by the addition of a second equivalent of di-n-butyl-amine, yielding the di-n-butyl-ammonium carboxyl-ate salt. The structure of the carboxyl-ate anion resembles that of the parent carb-oxy-lic acid. The main difference lies in the position of the H atom in the 4-hy-droxy group. In the anion the O-H bond is perpendicular, rather than parallel, to the benzyl ring. This position appears to facilitate hydrogen bonding to an O atom of the carboxyl-ate group of a symmetry-related anion. In addition, there are three N-H⋯O hydrogen bonds. In contrast, the neutral species hydrogen bonds via a carboxylic acid dimer. The dihedral angle between the benzene rings in the anion is 79.19 (7)°.

In the title compound, C(22)H(28)O(3)S, the dihedral angle between the two aromatic rings is 80.56 (6)°. The hy-droxy group is shielded by the two sterically hindered tert-butyl groups and therefore is not involved in any hydrogen bonding. The C-O-H fragment is coplanar with the aromatic ring, the dihedral angle between them being 7(5)°. In the crystal structure, pairs of mol-ecules are hydrogen bonded across crystallographic centers of symmetry.

The asymmetric unit of the title compound, [Pd(C(12)H(12)NO)(2)], consists of three crystallographically independent half-mol-ecules. Each Pd(II) atom lies on a center of inversion and is four-coordinated by two monoanionic forms of the amino-acryl-aldehyde in a square-planar geometry. In the crystal, adjacent mol-ecules are connected through C-H⋯π and C-H⋯O inter-actions into a three-dimensional polymeric structure.