Phenolic acids are naturally occurring compounds that are known for their antioxidant and antiradical activity. We present experimental and theoretical studies on the antioxidant potential of the set of 22 phenolic acids with different models of hydroxylation and methoxylation of aromatic rings. Ferric reducing antioxidant power assay was used to evaluate this property. 2,3-dihydroxybenzoic acid was found to be the strongest antioxidant, while mono hydroxylated and methoxylated structures had the lowest activities. A comprehensive structure–activity investigation with density functional theory methods elucidated the influence of compounds topology, resonance stabilization, and intramolecular hydrogen bonding on the exhibited activity. The key factor was found to be a presence of two or more hydroxyl groups being located in ortho or para position to each other. Finally, the quantitative structure–activity relationship approach was used to build a multiple linear regression model describing the dependence of antioxidant activity on structure of compounds, using features exclusively related to their topology. Coefficients of determination for training set and for the test set equaled 0.9918 and 0.9993 respectively, and Q2 value for leave-one-out was 0.9716. In addition, the presented model was used to predict activities of phenolic acids that haven’t been tested here experimentally.

The foreign atom doping influences the properties of carbon materials, and it is a possible way of designing materials of desired characteristics. Density functional calculations have been carried out on various isomers of boron-doped (4,0) and (9,0) carbon nanotubes as templates to investigate the doping effect on the structure and electronic properties on such systems. The results indicate that these boron-doped carbon nanotubes show local structural changes, mostly due to the elongation of bonds. The insertion of heteroatoms perturbs the π-conjugation system, which, in effect, destabilizes the material through higher energy cost of formation. The position of the foreign atom controls the new organization of electron density and leads to one of two possible distributions, viz., global (where electron density is distributed over the molecular surface) or local (localized distribution of electron density). This feature, in turn, can influence the bonding of the reactants while interacting with the surface. The charge distribution at a particular boron-doped site always possesses the local characteristics with a positively charged boron atom surrounded by negatively charged carbons. Such a character is also a measure of the driving force for influencing the substitution reaction in the vicinity of boron through an ionic mechanism.

Due to an outbreak of COVID-19, the number of research papers devoted to in-silico drug discovery of potential antiviral drugs is increasing every day exponentially. Still, there is no specific drug to prevent or treat this novel coronavirus (SARS-CoV-2) disease. Thus, the screening for a potential remedy presents a global challenge for scientists. Up to date over a hundred crystallographic structures of SARS-CoV-2 M pro have been deposited to Protein Data Bank. With many known proteins, the demand for a reliable target has become higher than ever, so as the choice of an efficient computational methods. Therefore, in this study comparative methods have been used for receptor-based virtual screening, targeting 9 selected structures of viral M pro. Reliability analyses followed by re-docking of the specific co-crystallized ligand provided the best reproductivity for structures with PDB ID 6LU7, 6Y2G and 6Y2F. The influence of crystallographic water on an outcome of a virtual screening against selected targets was also investigated. Once the most reliable targets were selected, the library of easy purchasable natural compounds were retrieved from the MolPort database (10,305 compounds) and docked against the selected M pro proteins. To ensure the efficiency of the selected compounds, binding energies for top-15 hit ligands were calculated using Molecular Mechanics as well as their absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties were predicted. Based on predicted binding energies and toxicities, top-5 compounds were selected and subjected to Molecular Dynamics simulation and found to be stable in complex to act as possible inhibitors for SARS-CoV-2.

Non-noble metal based electrocatalysts for hydrogen evolution reactions hold great potential for commercial applications. However, effective design strategies are highly needed to manipulate the catalyst structures for high activity and...

A D‐π‐A (donor‐π bridge‐acceptor) dye with a conjugated dipicolylamine group as the donor was synthesized and characterized. When zinc is bound to the dipicolylamine ligand, charge transfer strength from the donor is decreased resulting in a large blue‐shift in the absorption spectrum with a quenching of dye emission. Upon addition of phosphate, changes in both the absorption and emission spectrum are observed with intermediate states between the starting zinc complex and free dye observed. The zinc‐dye complex was found to react with two equivalents of phosphate or trace water to give the free dye. The water response is unexpected given the widespread use of the dipicolylamine group as an anion sensor in water. When the dipicolylamine group is part of conjugated D‐π‐A dye designs with zinc complexes, the dye is observed to act as a humidity sensor at low water amounts.