Synthesis, characterization and theoretical studies of a novel coumarin-triazole-thiophene hybrid 4-(((4-ethyl-5-(thiophen-2-yl)-4H-1,2,4-triazol-3-yl)thio)methyl)-6,7-dimethyl-2H-chromen-2-one (1), which was fabricated from 4-ethyl-5-(thiophen-2-yl)-4H-1,2,4-triazole-3-thiol and 4-(chloromethyl)-6,7-dimethyl-2H-chromen-2-one, are reported. The resulting compound was characterized by microanalysis, IR, ¹H, and ¹³C APT NMR spectroscopy. The DFT calculations examined the structure and electronic properties of 1 in gas phase. Its reactivity descriptors and molecular electrostatic potential revealed the reactivity and the reactive centers of 1. ADMET properties of 1 were evaluated using the respective online tools. It was established that 1 exhibit positive gastrointestinal absorption properties and negative human blood-brain barrier penetration. The Toxicity Model Report revealed that 1 belongs to toxicity class 4. Molecular docking was additionally applied to study the interaction of 1 with some SARS-CoV-2 proteins. It was established that the title compound is active against all the applied proteins with the most efficient interaction with Papain-like protease (PLpro). The interaction of 1 with the applied proteins was also studied using molecular dynamics simulations. Graphical abstract A novel coumarin-triazole-thiophene hybrid 4-(((4-ethyl-5-(thiophen-2-yl)-4H-1,2,4-triazol-3-yl)thio)methyl)-6,7-dimethyl-2H-chromen-2-one (1) is reported. The structure and electronic properties of 1 were examined by the DFT calculations. ADMET properties of 1 were also evaluated. Molecular docking and molecular dynamics simulations were applied to study interactions of 1 with a series of the SARS-CoV-2 proteins.

Coordination compounds are molecules that contain one or more metal centers bound to ligands. Ligands can be atoms, ions, or molecules that transfer electrons to the metal. These compounds can be charged or neutral. When charged, neighboring counter-ions help stabilize the complex. The metal ion is located at the center of a complex ion, surrounded by other molecules or ions known as ligands. Ligands can be thought of as covalently bonded to the core ion through coordination. Understanding coordination theory in chemistry provides insight into the geometric shape of complexes and the structure of coordination compounds, which consist of a central atom or molecule connected to surrounding atoms or compounds. Inorganic coordination compounds exhibit different properties and are used in synthesizing organic molecules. The coordination of chemicals is vital for the survival of living organisms. Metal complexes are also essential for various biological processes, with many enzymes, known as metalloenzymes, being composed of metal complexes. These metal complexes occur naturally.

Iron corrosion in acidic environments poses a significant challenge in various industries. This study explores the relationship between theoretical parameters and experimental data for organic corrosion inhibitors applied to iron surfaces in 1 M HCl solution at 25 °C. The review analyzes studies employing various techniques, primarily Electrochemical Impedance Spectroscopy (EIS), to assess inhibitor efficiency (IE%). Key theoretical parameters like E _binding (interaction strength) and Δ N (electron transfer) are investigated for their ability to predict IE%. The findings reveal a strong correlation between experimental IE% and E _binding , suggesting the potential of E _binding as a reliable predictor of inhibitor performance before experimentation. While Δ N demonstrates promise in evaluating inhibitor effectiveness, further validation is necessary. Furthermore, the review emphasizes the possibility of using a single standardized method like EIS for inhibitor efficiency evaluation due to consistent results observed across studies with standardized conditions. Additionally, the influence of factors like molecular structure, surface interactions, and temperature on inhibitor effectiveness is highlighted. Higher inhibitor concentrations and lower temperatures generally resulted in improved corrosion inhibition. This review underscores the importance of a combined theoretical and experimental approach for the development of efficient and optimized corrosion inhibitors for iron in acidic environments.

This work presents a multiscale theoretical investigation into the potential of quinoxaline derivatives (Q1–Q6) as corrosion inhibitors for various metals (Fe(110), Cu(111), and Al(110)). Employing a combined approach combining density functional theory (DFT) and Monte Carlo simulations, we explore the relationship between molecular structure, electronic properties, and adsorption behavior. Density functional theory (DFT) and molecular dynamics simulations (MDS) were used to investigate the electronic characteristics of diverse compounds. The study included key parameters including highest occupied molecular orbital energy ( E _HOMO ), lowest unoccupied molecular orbital energy ( E _LUMO ), energy gap ( E _g ) between E _LUMO and E _HOMO , dipole moment, global hardness, softness ( σ ), ionization energy ( I ), electron affinity ( A ), electronegativity ( χ ), back-donation energy E _b−d , global electrophilicity ( ω ), electron transfer, global nucleophilicity ( ε ), and total energy (sum of electronic and zero-point energies). These properties, alongside adsorption energies (following the trend Q6 > Q2 > Q3 > Q4 > Q5 > Q1), are used to identify promising inhibitor candidates and establish structure–property relationships governing their effectiveness. The results suggest that inhibitor efficiency increases with a decreasing energy gap between frontier orbitals. Notably, the protonated state of Q6 exhibits high reactivity, low stability, and strong adsorption, making it a potential candidate for further exploration. This comprehensive theoretical approach offers crucial insights for the conceptual development of new and powerful corrosion inhibitors.