Di-n-butyl­ammonium 2-[(3,5-di-tert-butyl-4-hy­droxy­benz­yl)sulfan­yl]benzoate

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 carb­oxy­lic acid [Alhadi et al. (2010). Acta Cryst. E66, o1787] by the addition of a second equivalent of di-n-butyl­amine, yielding the di-n-butyl­ammonium carboxyl­ate salt. The structure of the carboxyl­ate anion resembles that of the parent carb­oxy­lic acid. The main difference lies in the position of the H atom in the 4-hy­droxy 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 carboxyl­ate 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)°.