Insight into crystal structure of 2-methylquinolin-1-ium 2-carboxy-3-nitrobenzoate salt: Hirshfeld surface analysis, quantum chemical approach, and anti-bacterial activityGaneshkumar Palanisami, Theivarasu Chinniagounder, and Gomathi Venkatachalam Department of Chemistry, PSG College of Technology, Coimbatore, India
E-mail: theiva_psg@yahoo.co.in Received: 1 May 2024 Accepted: 1 November 2024 Abstract: The 2-methylquinolin-1-ium 2-carboxy-3-nitrobenzoate (2MQ2C3NB) salt was synthesized through a gradual evaporation of the solvent at room temperature with space group of P21/c. This molecular salt was analysed by single-crystal and powdered X-ray diffraction method, FT-IR, 1H and 13C NMR analysis, UV–Vis-NIR, and thermal analysis. In this molecular salt, one of the carboxylic protons, particularly from C1-carboxyl group of 2-carboxy-3-nitrobenzoic acid, shifted to the N-atom of 2-methylquinoline. The 2-methylquinolin-1-ium (2MQ+) cation and 2-carboxy-3-nitrobenzoate (2C3NB−) anion form 1D chain separately. The interactions between these two 1D chains lead to the extension of 2D supramolecular chains. The Hirshfeld surfaces of 2MQ2C3NB salt illustrate N–H….O/ O–H…O bonding as dominant interactions. Further this salt is assisted by other weak interactions such as H….H, C….H, C–H….O bonds and some degree of π…π interactions among quinolinium moiety with the centroid distance of 3.62 Å. The UV–Vis-NIR spectra of this molecular salt exhibit 78% transmission in the visible area which depicts the suitability for optical applications. The photoluminescence spectrum illustrates that this molecular salt shows blue light emission. Using the B3LYP/6-311G + + (d,p) basis set, density functional theory (DFT) was employed to accomplish the quantum chemical calculations such as geometry optimization, natural bond orbital analysis (NBO), Frontier molecular orbital analysis (FMOA), molecular electrostatic potential surface (MEPS), and natural population analysis (NPA’s) to comprehend the structure–property correlation. The molecular salt was screened for anti-bacterial activity against four pathogenic microorganisms such as gram-negative Klebsiella pneumonia, Escherichia coli and gram-positive Bacillus subtilis, Staphylococcus aureus, and it has good binding affinity with the proteins established by docking data. Keywords: 2-Methylquinoline; 2-Carboxy-3-nitrobenzoic acid; Hydrogen bonding; Hirshfeld surfaces; Density functional theory Full paper is available at www.springerlink.com. DOI: 10.1007/s11696-024-03794-8
Chemical Papers 79 (1) 463–480 (2025) |
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