The 1:2 co-crystal formed between N, N'-bis(pyridin-4-ylmeth-yl)ethanedi-amide and benzoic acid: crystal structure, Hirshfeld surface analysis and computational study

Abstract

The crystal and mol-ecular structures of the title 1:2 co-crystal, C₁₄H₁₄N₄O₂·2C₇H₆O₂, are described. The oxalamide mol-ecule has a (+)-anti-periplanar conformation with the 4-pyridyl residues lying to either side of the central, almost planar C₂N₂O₂ chromophore (r.m.s. deviation = 0.0555 Å). The benzoic acid mol-ecules have equivalent, close to planar conformations [C₆/CO₂ dihedral angle = 6.33 (14) and 3.43 (10)°]. The formation of hy-droxy-O-H⋯N(pyrid-yl) hydrogen bonds between the benzoic acid mol-ecules and the pyridyl residues of the di-amide leads to a three-mol-ecule aggregate. Centrosymmetrically related aggregates assemble into a six-mol-ecule aggregate via amide-N-H⋯O(amide) hydrogen bonds through a 10-membered {⋯HNC₂O}₂ synthon. These are linked into a supra-molecular tape via amide-N-H⋯O(carbon-yl) hydrogen bonds and 22-membered {⋯HOCO⋯NC₄NH}₂ synthons. The contacts between tapes to consolidate the three-dimensional architecture are of the type methyl-ene-C-H⋯O(amide) and pyridyl-C-H⋯O(carbon-yl). These inter-actions are largely electrostatic in nature. Additional non-covalent contacts are identified from an analysis of the calculated Hirshfeld surfaces.

Keywords: Hirshfeld surface analysis; computational chemistry; crystal structure; hydrogen bonding; oxalamide.