In silico analyses of betulin: DFT studies, corrosion inhibition properties, ADMET prediction, and molecular docking with a series of SARS-CoV-2 and monkeypox proteins.

We report detailed computational studies of betulin - a pentacyclic naturally occuring triterpene, which is a precursor for a broad family of biologically active derivatives. The structure, electronic, and optical properties of betulin were studied by the density functional theory (DFT) calculations in gas phase. The reactivity and the reactive centers of betulin were revealed through its global reactivity descriptors and molecular electrostatic potential (MEP). The DFT calculations were also applied to probe betulin as a potential corrosion inhibitor for some important metals used in implants. Electron charge transfer from the molecule of betulin to the surface of all the examined metals (Ti, Fe, Zr, Co, Cu, Cr, Ni, Mn, Mo, Zn, Al, W, Ag, Au) was revealed, of which the best results were obtained for Ni, Au and Co. Bioavailability, druggability as well as absorption, distribution, metabolism, excretion and toxicity (ADMET) properties of betulin were evaluated using the SwissADME, BOILED-Egg and ProTox-II tools. Molecular docking was applied to examine the influence of the title compound on a series of the SARS-CoV-2 proteins as well as one of the monkeypox proteins. It was established that betulin is active against all the applied proteins with the best binding affinity with papain-like protease (PLpro) and spike protein (native) of SARS-CoV-2. The title compound is also active against the studied monkeypox protein. Interaction of betulin with papain-like protease (PLpro) was studied using molecular dynamics simulations.

Correction: Sharov et al. Computational Analysis of Molnupiravir. Int. J. Mol. Sci. 2022, 23, 1508.

We received a complaint from the Université Catholique de Louvain [...].

Computational Analysis of Molnupiravir.

In this work, we report in-depth computational studies of three plausible tautomeric forms, generated through the migration of two acidic protons of the N4-hydroxylcytosine fragment, of molnupiravir, which is emerging as an efficient drug to treat COVID-19. The DFT calculations were performed to verify the structure of these tautomers, as well as their electronic and optical properties. Molecular docking was applied to examine the influence of the structures of the keto-oxime, keto-hydroxylamine and hydroxyl-oxime tautomers on a series of the SARS-CoV-2 proteins. These tautomers exhibited the best affinity behavior (-9.90, -7.90, and -9.30 kcal/mol, respectively) towards RdRp-RTR and Nonstructural protein 3 (nsp3_range 207-379-MES).

Supramolecular structures of NiII and CuII with the sterically demanding Schiff base dyes driven by cooperative action of preagostic and other non-covalent interactions.

This work reports on synthesis and extensive experimental and theoretical investigations on photophysical, structural and thermal properties of the NiII and CuII discrete mononuclear homoleptic complexes [Ni(L I,II)2] and [Cu(L I,II)2] fabricated from the Schiff base dyes o-HOC6H4-CH=N-cyclo-C6H11 (HL I) and o-HOC10H6-CH=N-cyclo-C6H11 (HL II), containing the sterically crowding cyclo-hexyl units. The six-membered metallocycles adopt a clearly defined envelope conformation in [Ni(L II)2], while they are much more planar in the structures of [Ni(L I)2] and [Cu(L I,II)2]. It has been demonstrated by in-depth bonding analyses based on the ETS-NOCV and Interacting Quantum Atoms energy-decomposition schemes that application of the bulky substituents, containing several C-H groups, has led to the formation of a set of classical and unintuitive intra- and inter-molecular interactions. All together they are responsible for the high stability of [Ni(L I,II)2] and [Cu(L I,II)2]. More specifically, London dispersion dominated intramolecular C-H⋯O, C-H⋯N and C-H⋯H-C hydrogen bonds are recognized and, importantly, the attractive, chiefly the Coulomb driven, preagostic (not repulsive anagostic) C-H⋯Ni/Cu interactions have been discovered despite their relatively long distances (∼2.8-3.1 Å). All the complexes are further stabilized by the extremely efficient intermolecular C-H⋯π(benzene) and C-H⋯π(chelate) interactions, where both the charge-delocalization and London dispersion constituents appear to be crucial for the crystal packing of the obtained complexes. All the complexes were found to be photoluminescent in CH2Cl2, with [Cu(L II)2] exhibiting the most pronounced emission - the time-dependent density-functional-theory computations revealed that it is mostly caused by metal-to-ligand charge-transfer transitions.