Exploring the differences in crystal structure landscapes and physicochemical properties of enrofloxacin through the number of -OH in coformers: A case study

An, Qi; Liu, Lixin; Li, Yujiao; Shi, Jingwen; Zhang, Yunan; Liu, Yingli; Zhang, Haiting; Wang, Yuning; Zhang, Xuan

doi:10.1016/j.molstruc.2024.138176

Cited by 1 publication

(1 citation statement)

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“…During the structure determination process, all C -H hydrogen atoms were positioned according to the expected distances dictated by crystallochemistry, as bond angles are strictly governed by the hybridization of the corresponding carbon atoms. However, the positioning of hydrogen atoms associated with alcoholic groups, which is directed by the torsional angle around the C -O bond axis, proved to be unfeasible through Rietveld refinement due to the limited resolution of the technique [43,44]. To address this limitation, first principle calculations were conducted using Gaussian16 to optimize the positions of the hydrogen atoms and achieve a more accurate characterization of the hydrogen bonding network.…”

Section: Crystal Structure Of 4-methylcatecholmentioning

confidence: 99%

The Peculiar H-Bonding Network of 4-Methylcatechol: A Coupled Diffraction and In Silico Study

Lopresti,

Palin,

Calegari

et al. 2024

Molecules

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The crystal structure of 4-methylcatechol (4MEC) has, to date, never been solved, despite its very simple chemical formula C7O2H8 and the many possible applications envisaged for this molecule. In this work, this gap is filled and the structure of 4MEC is obtained by combining X-ray powder diffraction and first principle calculations to carefully locate hydrogen atoms. Two molecules are present in the asymmetric unit. Hirshfeld analysis confirmed the reliability of the solved structure, since the two molecules show rather different environments and H-bond interactions of different directionality and strength. The packing is characterised by a peculiar hydrogen bond network with hydroxyl nests formed by two adjacent octagonal frameworks. It is noteworthy that the observed short contacts suggest strong inter-molecular interactions, further confirmed by strong inter-crystalline aggregation observed by microscopic images, indicating the growth, in many crystallization attempts, of single aggregates taller than half a centimetre and, often, with spherical shapes. These peculiarities are induced by the presence of methyl group in 4MEC, since the parent compound catechol, despite its chemical similarity, shows a standard layered packing alternating hydrophobic and polar layers. Finally, the complexity and peculiarity of the packing and crystal growth features explain why a single crystal could not be obtained for a standard structural analysis.

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Section: Crystal Structure Of 4-methylcatecholmentioning

confidence: 99%