title: A 2:1 co-crystal of 2-methyl-benzoic acid and N,N'-bis-(pyridin-4-ylmeth-yl)ethanedi-amide: crystal structure and Hirshfeld surface analysis.
abstract: The asymmetric unit of the title 2:1 co-crystal, 2C8H8O2·C14H14N4O2, comprises an acid mol-ecule in a general position and half a di-amide mol-ecule, the latter being located about a centre of inversion. In the acid, the carb-oxy-lic acid group is twisted out of the plane of the benzene ring to which it is attached [dihedral angle = 28.51 (8)°] and the carbonyl O atom and methyl group lie approximately to the same side of the mol-ecule [hy-droxy-O-C-C-C(H) torsion angle = -27.92 (17)°]. In the di-amide, the central C4N2O2 core is almost planar (r.m.s. deviation = 0.031 Å), and the pyridyl rings are perpendicular, lying to either side of the central plane [central residue/pyridyl dihedral angle = 88.60 (5)°]. In the mol-ecular packing, three-mol-ecule aggregates are formed via hy-droxy-O-H⋯N(pyrid-yl) hydrogen bonds. These are connected into a supra-molecular layer parallel to (12[Formula: see text]) via amide-N-H⋯O(carbon-yl) hydrogen bonds, as well as methyl-ene-C-H⋯O(amide) inter-actions. Significant π-π inter-actions occur between benzene/benzene, pyrid-yl/benzene and pyrid-yl/pyridyl rings within and between layers to consolidate the three-dimensional packing.
authors.affiliation: Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Syed
authors.affiliation: Department of Physics, Bhavan's Sheth R. A. College of Science, Ahmedabad, Gujarat 380 001, India.
authors.forename: Mukesh M
authors.initials: MM
authors.lastname: Jotani
authors.affiliation: Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Siti Nadiah Abdul
authors.initials: SN
authors.lastname: Halim
authors.affiliation: Centre for Crystalline Materials, Faculty of Science and Technology, Sunway University, 47500 Bandar Sunway, Selangor Darul Ehsan, Malaysia.
authors.forename: Edward R T
authors.initials: ER
authors.lastname: Tiekink
keywords: Hirshfeld surface analysis; carb­oxy­lic acid; co-crystal; crystal structure; di­amide; hydrogen bonding