Two new hydrogen-bonded supramolecular dioxo-molybdenum(VI) complexes based on acetyl-hydrazone ligands: Synthesis, crystal structure and DFT studies

New bis hydrazone: Synthesis, X-ray crystal structure, DFT computations, conformational study and in silico study of the inhibition activity of SARS-CoV-2

The aim of this work was to synthesize new bis hydrazone derived from benzil in good yield, namely: (1Z,2Z)-1,2-bis (3-Chlorophenyl Hydrazino) Benzil, encoded by 3-Cl BHB. The benzil (or 1,2-diphenyl ethanedione) reacts with 3-Cl phenyl hydrazine by reflux method using ethanol as solvent to obtain the target compound. The obtained product is depicted by UV-Vis, IR spectroscopy and XRD-crystals analysis. All various contacts intra and intermolecular found in 3-Cl BHB were determined by the X-ray diffraction technique performed on single crystals. On the other hand, the optimized geometric structure of 3-Cl BHB was computed by the DFT/B3LYP method with 6-31 G (d, p) level. So, the bond lengths and angles, frontier molecular orbitals (FMO), surface electrostatic potential of the molecule (MEP), global reactivity descriptors, Mulliken atomic charges, computed vibrational analysis and electronic absorption spectrum were determined to get a good understanding of the electronic properties and the active sites of 3-Cl BHB, then to compare them with experimental data. Additionally, a conformational study was carried out using the same method (DFT). The structure-activity relationships established through molecular docking studies showed that 3-Cl BHB structure strongly binds to the receptors Mpro (-8.90 Kcal/mol) and RdRp (-8.60 Kcal/mol) which confirm its inhibition activity against COVID-19.

The Role of Hydrogen Bonds in Interactions between [PdCl4]2- Dianions in Crystal

[PdCl4]2- dianions are oriented within a crystal in such a way that a Cl of one unit approaches the Pd of another from directly above. Quantum calculations find this interaction to be highly repulsive with a large positive interaction energy. The placement of neutral ligands in their vicinity reduces the repulsion, but the interaction remains highly endothermic. When the ligands acquire a unit positive charge, the electrostatic component and the full interaction energy become quite negative, signalling an exothermic association. Raising the charge on these counterions to +2 has little further stabilizing effect, and in fact reduces the electrostatic attraction. The ability of the counterions to promote the interaction is attributed in part to the H-bonds which they form with both dianions, acting as a sort of glue.

Intermolecular interactions in antipyrine-like derivatives 2-halo-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)benzamides: X-ray structure, Hirshfeld surface analysis and DFT calculations

Based on experimental and computational data, a complex network of intermolecular interactions has been rationalized for antipyrine compounds.