Jeraldine Maire Bourletidis How, Matthew C. Scheepers, Andreas Lemmerer and Mark G. Smith* The crystal structure of the co-crystal isonicotinamide · terephthalic acid, C8H6O4·2(C6H6N2O) https://doi.org/10.1515/ncrs-2024-0312 Received July 23, 2024; accepted September 16, 2024; published online October 1, 2024 Abstract C8H6O4·2(C6H6N2O), monoclinic, C2/c (no. 15), a = 20.8371(8) Å, b = 5.2243(2) Å, c = 19.1062(7) Å, β = 118.8350(10)°,V = 1822.01(12) Å3, Z = 4, Rgt(F ) = 0.0392, wRref(F 2) = 0.1143, T = 173 K. CCDC No.: 2312436 A part of the molecular structure is shown in the figure. Table 1 contains crystallographic data and Table 2 contains the list of the atoms including atomic coordinates and displacement parameters. 1 Source of materials Isonicotinamide and terephthalic acid were commercially sourced and not purified any further. 0.0204 g of iso- nicotinamide (0.167 mmol) and 0.0162 g terephthalic acid (0.0975 mmol) were dissolved in 1 ml of AP grade methanol while stirring at 50 °C. 200 μl of AP grade dimethyl sulphoxide was then added to the solution, which was then heated to 100 °C while stirring in a polytop vial. The solution was left to evaporate at room temperature, with the cap being left slightly open. Colourless block crystals formed after 10 days. 2 Experimental details First the non-hydrogen atoms were refined isotropically, then anisotropically by full matrix least-squares calculations based on F2. C-bound hydrogen atoms were placed at ideal- ized positions and were allowed to ride on their respective parent atoms with thermal displacement parameters 1.2 times of the parent C atom. The coordinates and isotropic displacement parameters of the N-bound and O-bound H atoms involved in hydrogen bonding interactions were allowed to refine isotropically. Diagrams and publication material were generated using ORTEP-3,4 WinGX5 and PLATON.6 Table : Data collection and handling. Crystal: Colourless block Size: . × . × .mm Wavelength: μ: MoKα radiation (. Å) .mm− Diffractometer, scan mode: θmax, completeness: Bruker APEX-II, φ and ω .°, >% N(hkl)measured, N(hkl)unique, Rint: , , . Criterion for Iobs, N(hkl)gt: Iobs > σ(Iobs),  N(param)refined:  Programs: Bruker, SHELX,, WinGX/ORTEP,, PLATON *Corresponding author: Mark G. Smith, Chemistry Department, University of South Africa, Unisa Science Campus, 28 Pioneer Avenue, Florida, Roodepoort Gauteng, South Africa, E-mail: smithm2@unisa.ac.za. https://orcid.org/0000-0003-2553-2540 Jeraldine Maire Bourletidis How, Chemistry Department, University of South Africa, Unisa Science Campus, 28 Pioneer Avenue, Florida, Roodepoort Gauteng, South Africa. https://orcid.org/0000-0002-0686-6257 Matthew C. Scheepers and Andreas Lemmerer, Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, Gauteng, South Africa Z. Kristallogr. - N. Cryst. Struct. 2024; 239(6): 1089–1090 Open Access. © 2024 the author(s), published by De Gruyter. This work is licensed under the Creative Commons Attribution 4.0 International License. https://doi.org/10.1515/ncrs-2024-0312 mailto:smithm2@unisa.ac.za https://orcid.org/0000-0003-2553-2540 https://orcid.org/0000-0002-0686-6257 3 Comment Isonicotinamide is an isomer of niacinamide, differing in the position of the carbamide substituent. Isonicotinamide, like niacinamide, is thought to be very useful in co-crystallization because the pyridine nitrogen easily acts as an acceptor for hydrogen bonds, especially when paired with good hydrogen bond donors, such as carboxylic acids and alco- hols. Isonicotinamide has been co-crystallized with many carboxylic acids, making use of the robust carboxylic acid/pyridine hydrogen bond.7 Isonicotinamide in its pure form crystallizes in the P21/c space group.8 Terephthalic acid, a dicarboxylic acid is used in the synthesis of metal organic frameworks as a linker between metal centres. It is also commonly used to prepare co-crystals with N-heterocyclic molecules.9 It is also frequently used in the development of saturated poly- esters.10 Terephthalic acid is also useful when preparing co- ordination polymers.11 Terephthalic acid in its pure form crystallizes in the P1̄ space group.12 The asymmetric unit of isonicotinamide ⋅ terephthalic contains one molecule of isonicotinamide and half a molecule of terephthalic acid, and crystallizes in the monoclinic C2/c space group. The completemolecule is generated by symmetry. There is an O2–H2/N2 hydrogen bond, formed between the hydrogen of the carboxyl group and the pyridine nitrogen atom. Being in the C2/c space group the crystal structure has a glide plane along the c axis. The isonicotinamide molecule is bonded to another isonicotinamide molecule through N1–H1A/O1 hydrogen bonds, forming an R(8) ring, and two terephthalic acid molecules via O2–H2/N2 and N1–H1B/O3 hydrogen bonds. Terephthalic acid is bonded to four iso- nicotinamide molecules via two N1–H1B/O3 hydrogen bonds and two O2–H2/N2 hydrogen bonds. Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission. Competing interests: The authors declare no conflicts of interest regarding this article. Research funding: This work was supported by the National Research Foundation (NRF) “Competitive Support for Unrated Researchers” grant Number CSUR23042597072 (Dr MG Smith) as well as the University of South Africa. References 1. Bruker. APEX3. SAINT–Plus and XPREP; Bruker AXS Inc.: Madison, Wisconsin, USA, 2016. 2. Sheldrick, G. M. Crystal Structure Refinement with SHELXL. Acta Crystallogr. 2015, C71, 3–8. 3. Sheldrick, G. M. SHELXTL – Integrated Space-Group and Crystal-Structure Determination. Acta Crystallogr. 2015, A71, 3–8. 4. ORTEP-3:Farrugia, L. J.WinGX and ORTEP for Windows: an Update. J. Appl. Crystallogr. 2012, 45, 849–854. 5. Farrugia, L. J. WinGX Suite for Small-Molecule Single-Crystal Crystallography. J. Appl. Crystallogr. 1999, 32, 837–838. 6. PLATON:Spek, A. L. Structure Validation in Chemical Crystallography. Acta Crystallogr. 2009, D65, 148–155. 7. Báthori, N. B.; Lemmerer, A.; Venter, G. A.; Bourne, S. A.; Caira, M. R. Pharmaceutical Co-crystals with Isonicotinamide-Vitamin B3, Clofibric Acid, and Diclofenac-and Two Isonicotinamide Hydrates. Cryst. Growth Des. 2011, 11, 75–87. 8. Jones, E. C. L.; Bebiano, S. S.; Ward, M. R.; Bimbo, L. M.; Oswald, I. D. H. Pressure-induced Superelastic Behaviour of Isonicotinamide. Chem. Commun. 2021, 57, 11827–11830. 9. Lemmerer, A.; Bernstein, J.; Kahlenberg, V. Hydrogen Bonding Patterns of the Co-crystal Containing the Pharmaceutically Active Ingredient Isoniazid and Terephthalic Acid. J. Chem. Crystallogr. 2011, 41, 991–997. 10. Luttrell, W. E.; Hester, R. L. Terephthalic Acid. J. Chem. Health Saf. 2016, 23, 49–52. 11. Hasanova, S. S.; Yolchueva, E. A.; Mashadi, A. Q.; Muhammad, S.; Ashfaq, M.; Muhammed, M. E.; Munawar, K. S.; Tahir, M. N.; Al-Sehemi, A. G.; Alarfaji, S. S. Synthesis, Characterization, Crystal Structures, and Supramolecular Assembly of Copper Complexes Derived from Nitroterephthalic Acid along with Hirshfeld Surface Analysis and Quantum Chemical Studies. ACS Omega 2023, 8, 8530–8540. 12. Bailey, M.; Brown, C. J. The Crystal Structure of Terephthalic Acid. Acta Crystallogr. 1967, 22, 387–391. Table : Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å). Atom x y z Uiso*/Ueq C . () . () . () . () C . () . () . () . () C . () . () . () . () H . . . .* C . () . () . () . () H . . . .* C . () . () . () . () H . . . .* C . () . () . () . () H . . . .* C . () . () . () . () C . () . () . () . () C . () . () . () . () H . . . .* C . () . () . () . () H . . . .* N . () −. () . () . () N . () . () . () . () O . () . () . () . () O . () . () . () . () O . () . () . () . () HA . () −. () . () .* HB . () −. () . () .* H . () . () . () .* 1090 J.M. Bourletidis How et al.: The crystal structure of the co-crystal isonicotinamide · terephthalic acid The crystal structure of the co-crystal isonicotinamide · terephthalic acid, C8H6O4·2(C6H6N2O) 1 Source of materials 2 Experimental details 3 Comment References << /ASCII85EncodePages false /AllowTransparency false /AutoPositionEPSFiles true /AutoRotatePages /None /Binding /Left /CalGrayProfile (Dot Gain 20%) /CalRGBProfile (sRGB IEC61966-2.1) /CalCMYKProfile (Euroscale Coated v2) /sRGBProfile (sRGB IEC61966-2.1) /CannotEmbedFontPolicy /Warning /CompatibilityLevel 1.7 /CompressObjects /Tags /CompressPages true /ConvertImagesToIndexed true /PassThroughJPEGImages false /CreateJobTicket false /DefaultRenderingIntent /Default /DetectBlends true /DetectCurves 0.1000 /ColorConversionStrategy /sRGB /DoThumbnails true /EmbedAllFonts true /EmbedOpenType false /ParseICCProfilesInComments true /EmbedJobOptions true /DSCReportingLevel 0 /EmitDSCWarnings false /EndPage -1 /ImageMemory 1048576 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