The structure and Hirshfeld surface analysis of the 4-amino 3-nitrobenzoic acid triclinic polymorph

• Published in: Structural chemistry 2024-06, Vol.35 (3), p.953-960
• Main Authors: Narmanova, F. S., Turaev, Kh. Kh, Kasimov, Sh. A., Ibragimov, A. B., Normamatov, A. S., Ruzmetov, A. Kh, Mengnorov, I. J., Balakrishnan, C., Eshimbetov, A. G., Ashurov, J. M.
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Computer Applications in Chemistry; Crystal structure; Differential thermal analysis; Nitrobenzoic acid; Phase transitions; Physical Chemistry; Polymorphism; Surface analysis (chemical); Theoretical and Computational Chemistry; Triclinic crystals
• ISSN: 1040-0400; 1572-9001
• DOI: 10.1007/s11224-024-02313-5

By preparation of 4-amino-3-nitrobenzoic acid (4-A3NBA-P) in the triclinic crystal form in contrast to known monoclinic crystals polymorphism of this compound has been established. The monoclinic form is called polymorph I, while triclinic crystals are designated as polymorph II. In the former polymorph, 4-A3NBA molecules are associated with the 3D network by H-bonds, while in the case of the latter polymorph, the H-bonded layers are incorporated into crystal structure by π•••π interactions. Therefore, Hirshfeld surface analyses indicate that the percentage of the O•••H/H•••O interactions of polymorph II (~ 39.1%) is less than that of polymorph I (54.5%). The TG-DTA studies attest that there is no “polymorph II → polymorph I” phase transition.