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Three new 1,3,4-oxadiazoles (1–3) have been synthesized. The crystal structure of two of them were solved by single crystal X-ray diffraction analysis and a detailed quantitative analysis of the weak noncovalent interactions have been performed by using DFT calculations. In both compounds, the formation of recurrent H-bonded motifs involving the 1,3,4-oxadiazole is observed. In addition, a variety of CH⋯π interactions are established, involving both aliphatic and aromatic C–H bonds and the π-system of the electron rich tert-butylphenyl ring. QTAIM analysis and NCI plots were used to study the nature and the extent of different intermolecular interactions observed in these structures, which were rationalized using MEP surface plots. [ABSTRACT FROM AUTHOR]

In this study, three new hydrazide-based Schiff bases (1–3) have been synthesized via sonication in good to excellent yields 73–90% and mainly characterized by UV-visible, IR, 1H-NMR and single crystal X-ray diffraction analysis. The crystal structure of compounds 1 and 2 is stabilized by N–H⋯O, C–H⋯O and C–H⋯N hydrogen bonds, as well as C–H⋯π contacts. In addition, weak π⋯π stacking interactions were observed in the structure of 2. A detailed analysis of the intermolecular interactions that stabilize the crystal packing has been performed by using Hirshfeld surface analysis and energy framework calculations were carried out to analyze and visualize the topology of the supramolecular assembly, indicating that the dispersion energy is dominant over the electrostatic one in the most energetic dimers of both compounds. The interaction energies associated with the noncovalent interactions observed in the crystal structures and the interplay between them have been calculated using DFT calculations. Moreover, these intermolecular interactions were also characterized by using both Bader's quantum theory of atoms in molecules (QTAIM) and NCI plots. The synthesized alkoxybenzylidene analogs of benzohydrazide and acetohydrazide were screened in vitro against soybean lipoxygenase and were found to show better activity than the standard indomethacin. Putative binding modes and comparison of binding interactions in the protein–ligand complex were analyzed by molecular docking studies. [ABSTRACT FROM AUTHOR]

To explore the operational role of noncovalent interactions in supramolecular architectures with designed topologies, a series of solid‐state structures of 2‐ and 4‐formylphenyl 4‐substituted benzenesulfonates was investigated. The compounds are 2‐formylphenyl 4‐methylbenzenesulfonate, C14H12O4S, 3a, 2‐formylphenyl 4‐chlorobenzenesulfonate, C13H9ClO4S, 3b, 2‐formylphenyl 4‐bromobenzenesulfonate, C13H9BrO4S, 3c, 4‐formylphenyl 4‐methylbenzenesulfonate, C14H12O4S, 4a, 4‐formylphenyl 4‐chlorobenzenesulfonate, 4b, C13H9ClO4S, and 4‐formylphenyl 4‐bromobenzenesulfonate, C13H9BrO4S, 4c. The title compounds were synthesized under basic conditions from salicylaldehyde/4‐hydroxybenzaldehydes and various aryl sulfonyl chlorides. Remarkably, halogen‐bonding interactions are found to be important to rationalize the solid‐state crystal structures. In particular, the formation of O…X (X = Cl and Br) and type I X…X halogen‐bonding interactions have been analyzed by means of density functional theory (DFT) calculations and characterized using Bader's theory of `atoms in molecules' and molecular electrostatic potential (MEP) surfaces, confirming the relevance and stabilizing nature of these interactions. They have been compared to antiparallel π‐stacking interactions that are formed between the arylsulfonates. [ABSTRACT FROM AUTHOR]

• The crystal structure of two bis 1,3,4-oxadiazoles have been solved. • A complete analysis of intermolecular interactions were performed. • DFT calculations were used to evaluate the relevance of the main intermolecular contacts. • AChE inhibitory activity and molecular docking analysis of both compounds were analyzed. Two new bis-1,3,4-oxadiazole derivatives have been synthesized and characterized. The crystal structure of both compounds were solved by single crystal X-ray diffraction analysis and a detailed quantitative analysis of the weak non-covalent interactions have been performed by using the Hirshfeld surface analysis and DFT calculations. The results indicate that both molecules showed different crystal packing. Compound 1 shows C-H ··· N and C-H ··· O hydrogen bonds and the structure is also stabilized by C-H ··· π, π ··· π stacking and lone pair (S) ··· π interactions, while the crystal structure of 2 is mainly stabilized by C-H ··· N and weak C-H ··· S contacts. The Hirshfeld surfaces, QTAIM analysis and NCI plots were used to study the nature and the extent of different intermolecular interactions observed in these structures. The AChE inhibitory activity of 1 and 2 was evaluated with reference to standard drug Galantamine. The AChE inhibitory activity of compound 1 showed better inhibitory activity (IC 50 = 36.34 µg/mL) as compared to compound 2 (IC 50 = 47.34 µg/mL). The molecular docking analysis of the inhibitors was performed to identify the putative binding modes and interactions inside the active pocket of the enzymes. This analysis also indicates that the studied compounds could act as "bulky"-blockers of the normal ionic substrate (ACh) entrance into the active site gorge of AChE. [Display omitted] [ABSTRACT FROM AUTHOR]