Crystal structure of the 1:2 co-crystal between N,N′-bis(4-pyridylmethyl)oxalamide and acetic acid as a dihydrate, C14H14N4O2⋅2 C2H4O2⋅2 H2O

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The crystal and molecular structures of the title 1:2 co-crystal, C14H14N4O2·2C7H6O2, are described. The oxalamide molecule has a (+)-antiperiplanar 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 molecules have equivalent, close to planar conformations [C6/CO2 dihedral angle = 6.33 (14) and 3.43 (10)°]. The formation of hydroxy-O—H...N(pyridyl) hydrogen bonds between the benzoic acid molecules and the pyridyl residues of the diamide leads to a three-molecule aggregate. Centrosymmetrically related aggregates assemble into a six-molecule aggregate via amide-N—H...O(amide) hydrogen bonds through a 10-membered {...HNC2O}2 synthon. These are linked into a supramolecular tape via amide-N—H...O(carbonyl) hydrogen bonds and 22-membered {...HOCO...NC4NH}2 synthons. The contacts between tapes to consolidate the three-dimensional architecture are of the type methylene-C—H...O(amide) and pyridyl-C—H...O(carbonyl). These interactions are largely electrostatic in nature. Additional non-covalent contacts are identified from an analysis of the calculated Hirshfeld surfaces.

The 1:2 co-crystal formed betweenN,N′-bis(pyridin-4-ylmethyl)ethanediamide and benzoic acid: crystal structure, Hirshfeld surface analysis and computational study

Tan

Tiekink

2020

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Crystal structure, Hirshfeld surface analysis and computational study of the 1:2 co-crystal formed between N,N′-bis(pyridin-4-ylmethyl)ethanediamide and 4-chlorobenzoic acid

Tan¹,

Tiekink²

2020

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The asymmetric unit of the title 1:2 co-crystal, C14H14N4O2·2C7H5ClO2, comprises two half molecules of oxalamide (4 LH2), as each is disposed about a centre of inversion, and two molecules of 4-chlorobenzoic acid (CBA), each in general positions. Each 4 LH2 molecule has a (+)antiperiplanar conformation with the pyridin-4-yl residues lying to either side of the central, planar C2N2O2 chromophore with the dihedral angles between the respective central core and the pyridyl rings being 68.65 (3) and 86.25 (3)°, respectively, representing the major difference between the independent 4 LH2 molecules. The anti conformation of the carbonyl groups enables the formation of intramolecular amide-N—H...O(amide) hydrogen bonds, each completing an S(5) loop. The two independent CBA molecules are similar and exhibit C6/CO2 dihedral angles of 8.06 (10) and 17.24 (8)°, indicating twisted conformations. In the crystal, two independent, three-molecule aggregates are formed via carboxylic acid-O—H...N(pyridyl) hydrogen bonding. These are connected into a supramolecular tape propagating parallel to [100] through amide-N—H...O(amide) hydrogen bonding between the independent aggregates and ten-membered {...HNC2O}2 synthons. The tapes assemble into a three-dimensional architecture through pyridyl- and methylene-C—H...O(carbonyl) and CBA-C—H...O(amide) interactions. As revealed by a more detailed analysis of the molecular packing by calculating the Hirshfeld surfaces and computational chemistry, are the presence of attractive and dispersive Cl...C=O interactions which provide interaction energies approximately one-quarter of those provided by the amide-N—H...O(amide) hydrogen bonding sustaining the supramolecular tape.

Crystal structure, Hirshfeld surface analysis and computational study of the 1:2 co-crystal formed between N,N′-bis[(pyridin-4-yl)methyl]ethanediamide and 3-chlorobenzoic acid

Tan¹,

Tiekink²

2020

Self Cite

The asymmetric unit of the title 1:2 co-crystal, C14H14N4O2·2C7H5ClO2, comprises a half-molecule of oxalamide (4 LH2), being located about a centre of inversion, and a molecule of3-chlorobenzoic acid (3-ClBA) in a general position. From symmetry, the 4 LH2 molecule has a (+)antiperiplanar 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)°; intramolecular amide-N—H...O(amide) hydrogen bonds are noted. The 3-ClBA molecule exhibits a small twist as seen in the C6/CO2 dihedral angle of 8.731 (12)°. In the molecular packing, three-molecule aggregates are formed via carboxylic acid-O—H...N(pyridyl) hydrogen bonding. These are connected into a supramolecular tape along [111] through amide-N—H...O(carbonyl) hydrogen bonding. Additional points of contact between molecules include pyridyl and benzoic acid-C—H...O(amide), methylene-C—H...O(carbonyl) and C—Cl...π(pyridyl) interactions 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 interaction is weak, and the importance of both electrostatic and dispersion terms in sustaining the molecular packing despite the strong electrostatic term provided by the carboxylic acid-O—H...N(pyridyl) hydrogen bonds.