Crystal structure, chemical reactivity, kinetic and thermodynamic studies of new ligand derived from 4-hydroxycoumarin Interaction with SARS-CoV-2

International audienceCurrently, Covid-19 pandemic infects staggering number of people around the  and causes a high rate of mortality. In order to fight this disease, a new coumarin derivative ligand (4-[(-3-) ]-2-chromen-2-one) (L) has been synthesized and characterized by single-crystal X-ray diffraction, NMR, ATR, UV-Visible and cyclic voltammetry. Chemical reactivity, kinetic and thermodynamic studies were investigated using DFT method. The possible binding mode between L and Main protease (Mpro) of SARS-CoV-2 and their reactivity were studied using molecular docking simulation. Single crystal X-ray diffraction showed that L crystallizes in a monoclinic system with 2  space group. The reactivity descriptors such as nucleophilic index confirm that L is more nucleophile, inducing complexation with binding species like biomolecules. The kinetic and thermodynamic parameters showed that the mechanism of crystal formation is moderately exothermic. The binding energy of the SARS-CoV-2/Mpro-L complex and the calculated inhibition constant using docking simulation showed that the active L molecule has the ability to inhibit SARS-CoV-2

A novel symmetrical mononuclear zinc complex: synthesis, crystal structure, Hirshfeld surface analysis, DFT calculations, and application in a supercapacitor electrode

International audienceThe development of supercapacitor electrodes based on metal complexes constitutes an interesting step toward different biomedical applications. In this context of research, a new Zn(DHA)2(DMSO)2 complex based on dehydroacetic acid (DHA) and dimethyl sulfoxide (DMSO) has been synthesized and structurally characterized. Suitable crystals for X-ray diffraction were collected by slow evaporation at room temperature. Single-crystal X-ray analysis revealed that the zinc ions bind through two carbonyl groups of the DHA ligand, and the titled complex is formed in a 1 : 2 metal–ligand stoichiometric ratio with an octahedral coordination geometry. Detailed Hirshfeld surface analysis and two-dimensional fingerprint plots were used to explore the intermolecular interactions in the material, and they revealed that the most significant contributions to the crystal packing are from H⋯H (45.5%), H⋯O/O⋯H (36.0%) and H⋯C/C⋯H (16.1%). In addition, using the DFT calculation method, the global descriptors are computed from the HOMO–LUMO orbitals, and the molecular reactivity sites are analyzed from an electrostatic potential map. Furthermore, an electrochemical study was carried out to estimate the energy storage capacity performance of the Zn(DHA)2(DMSO)2/graphene oxide (GO) hybrid material at a mass ratio of 100:1 which is sufficient for applications in many implantable health systems. The electrochemical results indicate that the Zn(DHA)2(DMSO)2/GO modified electrode exhibits excellent pseudo-capacitive behavior, with a specific capacitance of 36.40 F g−1 at 0.2 mA g−1 and a high specific energy (445 W h kg−1) at a high current (1 mA g−1). Excellent cycling stability with a specific capacitance retention of 105% after 2000 charge–discharge cycles at 10 mA g−1 was also observed. In summary, the Zn(DHA)2(DMSO)2/GO modified electrode can be explored as a supercapacitor electrode that can be applied in energy storage devices for biomedical electronics dedicated to health monitoring

Crystal structure, Hirshfeld surface and reactivity of novel ligand-L-AT1 derived from dehydroacetic acid: intermolecular interactions with SARS-Cov-2/main protease

International audienceThe crystals of new ligand, namely (3E)-6-methyl-3-{1-[(pyridin-3-ylmethyl) amino] ethylene}-2H-pyran-2, 4(3H)-dione) (L-AT1), were synthesized using the evaporation solution technique. Single-crystal X-ray diffraction and physico-chemical characterization (ATR, proton and carbon-13 NMR and UV-Visible) of L-AT1 were reported. In addition, Hirshfeld surface analysis (HSA) of the solid compound, structure optimization, Mulliken and NBO charges, global indices of reactivity, local reactivity descriptors and molecular electrostatic potential (MEP) of the ligand were investigated theoretically. XRD analysis showed that L-AT1 crystallizes in the triclinic space group P-1 and the structure was stabilized through hydrogen bonds. HAS revealed that H horizontal ellipsis H (46.5%) and O horizontal ellipsis H (25.7%) contacts are in control of crystal stacking. The energy gap (4.679 eV) and reactivity descriptors indicate the stability of L-AT1. The Mulliken and NBO charges showed that the protons have a positive charge and the heteroatoms exhibit negative charges. The Fukui function and MEP study revealed that the heteroatoms are the most reactive sites for an electophilic attack on the ligand. Molecular docking simulation shows that the significant binding affinity of L-AT1 with SARS-CoV-2/Mpro is due to the formation of high number of hydrogen bonds

Synthesis, spectral characterization, molecular modeling, antibacterial and antioxidant activities and stability study of binuclear Pd(II) and Ru(III) complexes with novel bis-[1-(2-[(2-hydroxynaphthalen-1-yl)methylidene]amino}ethyl)-1-ethyl-3-phenylthiourea] ligand Application to detection of cholesterol

International audienceA novel bis-[1-(2-[(2-hydroxynaphthalen-1-yl) methylidene]amino}ethyl)-1-ethyl-3-phenylthiourea] Schiff base (L) and its binuclear palladium and ruthenium complexes have been prepared and characterized by ESI-MS, elemental analysis, NMR (H NMR, C NMR, COSY, NEOSY and HSQC), FT-IR, ATR, UV-Visible spectra, TGA measurements, conductivity and cyclic voltammetry. The experimental results and the molecular parameters calculated using DFT method revealed a square planar geometry around Pd and octahedral geometry around ruthenium metal. The antibacterial activity of the ligand L and its complexes was evaluated against different human bacteria. In addition, the formation constants of the synthesized Schiff base-metal complexes and the systems formed with these chelates and cholesterol were estimated using spectrophotometric technique. The detection of cholesterol using novel Pd and Ru Schiff base complexes was studied using fluorometric method, and the measurements showed that the sensitive fluorometric response towards cholesterol analysis was determined using palladium complex. The limit of detection (LOD) of cholesterol calculated using this complex (4.6 μM) is lower (better) than LOD found using ruthenium complex (19.1 μM) and different compounds previously published around linear range of 0-5 mM