A 1:2 co-crystal of 2,2′-di­thiodi­benzoic acid and benzoic acid: crystal structure, Hirshfeld surface analysis and computational study

The asymmetric unit of the title 1:2 co-crystal, C(14)H(10)O(4)S(2)·2C(7)H(6)O(2), comprises half a mol­ecule of di­thiodi­benzoic acid [systematic name: 2-[(2-carb­oxy­phen­yl)disulfan­yl]benzoic acid, DTBA], as the mol­ecule is located about a twofold axis of symmetry, and a mol­ecule of benzoic acid (BA). The DTBA mol­ecule is twisted about the di­sulfide bond [the C—S—S—C torsion angle is −83.19 (8)°] resulting in a near perpendicular relationship between the benzene rings [dihedral angle = 71.19 (4)°]. The carb­oxy­lic acid group is almost co-planar with the benzene ring to which it is bonded [dihedral angle = 4.82 (12)°]. A similar near co-planar relationship pertains for the BA mol­ecule [dihedral angle = 3.65 (15)°]. Three-mol­ecule aggregates are formed in the crystal whereby two BA mol­ecules are connected to a DTBA mol­ecule via hy­droxy-O—H⋯O(hydroxy) hydrogen bonds and eight-membered {⋯HOC=O}(2) synthons. These are connected into a supra­molecular layer in the ab plane through C—H⋯O inter­actions. The inter­actions between layers to consolidate the three-dimensional architecture are π–π stacking inter­actions between DTBA and BA rings [inter-centroid separation = 3.8093 (10) Å] and parallel DTBA-hy­droxy-O⋯π(BA) contacts [O⋯ring centroid separation = 3.9049 (14) Å]. The importance of the specified inter­actions as well as other weaker contacts, e.g. π–π and C—H⋯S, are indicated in the analysis of the calculated Hirshfeld surface and inter­action energies.