Co-crystallization of 3,5-dinitrobenzoic acid with two antipsychotic agents: A simple 1:1 salt with trihexyphenidyl and a 1:2 acid salt containing a very short O - H⋯O hydrogen bond with chlorprothixene

Co-crystallization of racemic 1-cyclohexyl-1-phenyl-3-(piperidin-1-yl)propan-1-ol (trihexyphenidyl) with 3,5-dinitrobenzoic acid gives a simple 1:1 salt, namely 1-(3-cyclohexyl-3-hydroxy-3-phenylpropyl)piperidin-1-ium 3,5-dinitrobenzoate, C 20 H 32 NO + ·C 7 H 3 N 2 O 6 -, (I), whereas a similar co-crystallization using (Z)-3-(2-chloro-9H-thioxanthen-9-yl)-N,N-dimethylpropan-1-amine (chlorprothixene) gives a 1:2 acid salt, namely (Z)-3-(2-chloro-9H-thioxanthen-9-yl)-N,N-dimethylpropan-1-aminium hydrogen bis(3,5-dinitrobenzoate), C 18 H 19 ClNS + ·[H(C 7 H 3 N 2 O 6) 2 ] -, (II), the anion of which contains a very short O - H⋯O hydrogen bond, with dimensions O - H = 1.04 (3) Å, H⋯O = 1.41 (3) Å, O⋯O = 2.4197 (15) Å and O - H⋯O = 161 (3)°. In the cation of (I), the cyclohexyl and piperidyl rings both adopt chair conformations, whereas in the cation of (II), the central heterocyclic ring adopts a boat conformation, so that the dihedral angle between the two aryl rings is 41.56 (4)°. A combination of O - H⋯O, N - H⋯O and C - H⋯O hydrogen bonds links the ions of (I) into a complex chain of rings, and these chains are linked into sheets by π-π stacking interactions between inversion-related pairs of anions. In compound (II), a different combination of O - H⋯O, N - H⋯O and C - H⋯O hydrogen bonds links the ions into sheets. Comparisons are made with some related structures.