Abstract
The asymmetric unit of the title 1:2 co-crystal, C14H14N4O2·2C7H5ClO2, comprises a half-mol-ecule of oxalamide (4 LH2), being located about a centre of inversion, and a mol-ecule of3-chloro-benzoic acid (3-ClBA) in a general position. From symmetry, the 4 LH2 mol-ecule has a (+)anti-periplanar conformation with the 4-pyridyl residues lying to either side of the central, planar C2N2O2 chromophore with the dihedral angle between the core and pyridyl ring being 74.69 (11)°; intra-molecular amide-N-H⋯O(amide) hydrogen bonds are noted. The 3-ClBA mol-ecule exhibits a small twist as seen in the C6/CO2 dihedral angle of 8.731 (12)°. In the mol-ecular packing, three-mol-ecule aggregates are formed via carb-oxy-lic acid-O-H⋯N(pyrid-yl) hydrogen bonding. These are connected into a supra-molecular tape along [111] through amide-N-H⋯O(carbon-yl) hydrogen bonding. Additional points of contact between mol-ecules include pyridyl and benzoic acid-C-H⋯O(amide), methyl-ene-C-H⋯O(carbon-yl) and C-Cl⋯π(pyrid-yl) inter-actions so a three-dimensional architecture results. The contributions to the calculated Hirshfeld surface are dominated by H⋯H (28.5%), H⋯O/O⋯H (23.2%), H⋯C/C⋯H (23.3%), H⋯Cl/Cl⋯H (10.0%) and C⋯Cl/C⋯Cl (6.2%) contacts. Computational chemistry confirms the C-Cl⋯π inter-action is weak, and the importance of both electrostatic and dispersion terms in sustaining the mol-ecular packing despite the strong electrostatic term provided by the carb-oxy-lic acid-O-H⋯N(pyrid-yl) hydrogen bonds.
Highlights
The asymmetric unit of the title 1:2 co-crystal, C14H14N4O2Á2C7H5ClO2, comprises a half-molecule of oxalamide (4LH2), being located about a centre of inversion, and a molecule of3-chlorobenzoic acid (3-ClBA) in a general position
Threemolecule aggregates are formed via carboxylic acid-O—HÁ Á ÁN(pyridyl) hydrogen bonding
These are connected into a supramolecular tape along [111] through amide-N—HÁ Á ÁO(carbonyl) hydrogen bonding
Summary
The X-ray crystal structure determination of the 1:2 cocrystal formed between bis(pyridin-4-ylmethyl)ethanediamide and 3-chlorobenzoic acid, (I), is described. The present crystallographic study continues recent studies into the structural chemistry of the isomeric bis(pyridin-n-ylmethyl)ethanediamide molecules, i.e. species with the general formula nNC5H4CH2N(H)C( O)C( O)CH2C5H4N-n, for n = 2, 3 and 4, and hereafter, abbreviated as nLH2 (Tiekink, 2017). These molecules have interest as co-crystal co-formers as they possess both hydrogen-bonding donating and accepting sites, i.e. amide and pyridyl functionalities. 2020b) in order to probe for the possibility of competing/complementary halogen-bonding interactions In connection with this theme, this report describes the crystal and molecular structures of (I), along with a detailed analysis of the supramolecular association through the calculation of the Hirshfeld surface and computational chemistry. Symmetry codes: (i) Àx þ 1; Ày; Àz; (ii) Àx þ 1; Ày þ 1; Àz þ 1; (iii) x À 1; y; z; (iv) x; y þ 1; z þ 1; (v) Àx þ 2; Ày þ 1; Àz; (vi) x þ 1; y þ 1; z þ 1
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