Chemistry

This paper presents accurate TD-DFT calculations for several mixed-ligand gold(III) complexes with ligands including Cl⁻, Br⁻, I⁻, OH⁻, and NH₃. The calculated results show excellent agreement with available experimental data. The spectral shapes are determined by charge transfer transitions, which are systematically influenced by the ligand’s position in the spectrochemical series. The main vertical electron transitions and the molecular orbitals involved are identified and discussed. Furthermore, the results indicate that the iodide-containing gold(III) complexes, [AuCl₂I₂]⁻ and [AuI(OH)₃]⁻, are viable candidates for practical synthesis.

This study examines the activity coefficients of benzene, toluene, and di-(2-ethylhexyl)phosphoric acid (D2EHPA) in binary benzene–D2EHPA and toluene–D2EHPA systems, as well as the ternary n-hexane–toluene–D2EHPA system, using gas chromatography at 293.0 K. The primary objective was to determine UNIFAC model interaction parameters and validate their accuracy for predicting thermodynamic behavior in these systems. Experimental measurements revealed activity coefficient maxima for benzene and toluene at mole fractions of 0.8–0.9, decreasing to 0.46–0.67 in dilute solutions. The UNIFAC interaction parameters were calculated as follows: ACH–HPO₄ (−334, 4605), ACCH₃–HPO₄ (680, 467), and refined CH₂–HPO₄ (54, 1199). The UNIFAC model achieved deviations of less than 2% from experimental data in both binary and ternary systems. A novel methodology incorporating intermediate standards for gas chromatography was developed to overcome challenges in measuring volatile solvent concentrations, enhancing measurement precision. These findings enable accurate prediction of activity coefficients in mixtures of alkanes, cycloalkanes, and monoaromatic hydrocarbons with D2EHPA, offering significant implications for optimizing metal liquid–liquid extraction processes.

Benzimidazole derivatives are a privileged family of heterocyclic compounds that have remarkable structural diversity and find various pharmacological and industrial applications. In this article, we report on their synthetic procedures, ranging from classic condensation methodologies to modern green chemistry methodologies (microwave-assisted methods and catalyst-free methods). The biological significance of these derivatives is discussed, and their anticancer, antimicrobial, anti-inflammatory, antioxidant, antiparasitic, antiviral, antihypertensive, antidiabetic, and neuroprotective activities are reported. This article also reviews recent industrial applications, with special reference to hydrogen storage and environmental sustainability. The latest computational techniques, such as density functional theory (DFT), molecular docking, and molecular dynamics simulation, are particularly emphasized because they can be instrumental in understanding structure–activity relationships and rational drug design. In summary, the present review describes the importance of new benzimidazole derivatives, which are considered a different class of multitarget agents in medicinal chemistry and computational drug design.