A 2:1 co-crystal of 2-methylbenzoic acid and N,N '-bis(pyridin-4-ylmethyl)ethanediamide: crystal structure and Hirshfeld surface analysis

The asymmetric unit of the title 2:1 co-crystal, 2C(8)H(8)O(2)center dot C14H14N4O2, comprises an acid molecule in a general position and half a diamide molecule, the latter being located about a centre of inversion. In the acid, the carboxylic acid group is twisted out of the plane of the benzene ring to which it is attached [dihedral angle = 28.51 (8)degrees] and the carbonyl O atom and methyl group lie approximately to the same side of the molecule [hydroxy-O-C-C-C(H) torsion angle = -27.92 (17)degrees]. In the diamide, the central C4N2O2 core is almost planar (r.m.s. deviation = 0.031 angstrom), and the pyridyl rings are perpendicular, lying to either side of the central plane [central residue/pyridyl dihedral angle = 88.60 (5)degrees]. In the molecular packing, three-molecule aggregates are formed via hydroxy-O-H center dot center dot center dot N(pyridyl) hydrogen bonds. These are connected into a supramolecular layer parallel to (12 (2) over bar) via amide-N-H center dot center dot center dot O(carbonyl) hydrogen bonds, as well as methylene-C-H center dot center dot center dot O(amide) interactions. Significant pi-pi interactions occur between benzene/benzene, pyridyl/benzene and pyridyl/pyridyl rings within and between layers to consolidate the three-dimensional packing.