In the current study, the DFT and TD-DFT methods are used to investigate seven donor–π-acceptor (D–π–A) dyes, named DY01 to DY07, which are planned for utilization in DSSCs. The HOMO-LUMO gaps are decreased due to the solvent effect by 0.05-0.16 eV and are smallest (1.85 eV) for DY01. Frontier molecular orbitals show that charge separation is efficient between triphenylamine donor and cyanoacrylic acid acceptor. The bathochromic shift due to the solvent effects is estimated by the TD-DFT calculations, and DY01 exhibits the maximum red shift (638 nm) as well as DY05 has the highest oscillator strength (f = 1.664). Photovoltaic parameters reveal that DY01 is the most efficient (0.958), and DY02 could receive the relatively better electrons injection strength accompanied with high Voc value. Adsorption on (TiO₂)₈ cluster has an additional decrease the energy gaps and DY01 and DY07 show strong red shifts. Upon adsorption, the orbital distribution shows strong electronic coupling conducive to photo-induced electron transfer to the semiconductor. It can be concluded that DY01 is the most efficient sensitizer showing highest quantum efficiency due to its narrow band gap, effective intramolecular charge transfer (ICT), high light-harvesting efficiency (LHE) and favorable interfacial properties.

This study presents the synthesis and characterization of the novel compound 6,6'-(1,3,4-oxadiazole-2,5-diyl)bis(3-chloroaniline), using 1H NMR, 13C NMR, mass spectrometry and FTIR-ATR infrared spectroscopy. Density Functional Theory (DFT) calculations at the B3LYP/6-311G (d,p) level, were employed to optimize the molecular geometry and evaluate electronic properties. Frontier molecular orbital, molecular electrostatic potential, Parr function, and electron localization function analyses revealed an ambiphilic character, with electrophilic sites localized on the oxadiazole core and nucleophilic regions on the chloroaniline moieties. Molecular docking demonstrated high binding affinities toward Topoisomerase IV, Tubulin, and CDK2, surpassing standard ligands and indicating potential antibacterial and anticancer activities. ADME/Toxicity predictions suggested good pharmacokinetic behavior and low toxicity. Monte Carlo and molecular dynamics simulations confirmed strong and stable adsorption of the novel compound OBA on the Fe (110) surface, supporting its efficiency as a corrosion inhibitor.

This investigation employs Molecular Electron Density Theory (MEDT) to elucidate the stereoselective (4+2) cycloaddition between 1-(furan-2-yl)propan-1-one and 1-R-1H-pyrrole-2,5-dione, combining mechanistic and pharmacological analyses. DFT calculations at the M06/6-311++G(d,p) level identified six distinct reaction pathways, revealing the exo cycloadduct as the thermodynamically favored product, consistent with experimental observations. Transition state analysis through NCI revealed stabilizing CH-π and van der Waals interactions governing the exo preference. Beyond mechanistic insights, the derived norcantharimide analogues exhibit promising anticancer potential, with strong binding affinities against hematological malignancy targets. SwissADME profiling confirmed optimal drug-likeness (QED > 0.6, TPSA < 100 Ų) and low hepatotoxicity risk. Notably, molecular dynamics simulations established exceptional stability for lead compound P2d (RMSD 75%) to key catalytic residues. These integrated computational results position these derivatives as viable candidates for blood cancer therapeutics, merging rigorous mechanistic understanding with preclinical potential assessment.

The usefulness of various quantum chemical algorithms (semiempirical, HF, DFT) for predicting the energy and geometry of transition states of polar pseudocyclic processes was analyzed using the example of a model cycloaddition process between (Z)-C,N-diphenylnitrone and (E)-2-phenyl-1-nitroethene. These studies clearly recommend the ωB97XD functional in 6-311+G(d) basis set as the relatively most precise tool for studying the mechanisms of polar pseudocyclic processes.

Dye-sensitized solar cells (DSSCs) offer several advantages over traditional silicon-based solar cells, such as lower cost, versatility, and transparency. Titanium dioxide (TiO2) is widely used as a photocatalyst in DSSCs due to its chemical stability, high photocatalytic activity, photostability, and non-toxicity. This study provides a computational analysis of the geometric, electronic, optical, and photovoltaic properties of ten novel dyes using Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT). To our knowledge, these dyes have not been previously explored in the literature. Our findings indicate that structural modifications can significantly enhance the electronic, optical, and photovoltaic properties of these dyes. The B3LYP functional was identified as the most effective for predicting the geometric and electronic properties, while TD-DFT calculations with the CAM-B3LYP functional and the 6-31G(d,p) basis set accurately predicted the absorption properties. The absorption maxima of the dyes ranged from 427.82 nm to 755.93 nm, with strong UV-Vis absorption attributed to delocalized π-π* transitions. The calculated band gaps varied from 1.928 eV to 2.425 eV, showing that increased conjugation leads to reduced band gaps and improved dye performance. Open-circuit voltage (Voc) values for TiO₂ ranged from 0.893 eV to 1.38 eV, suggesting good potential for efficient electron injection into the TiO2 conduction band. In conclusion, the ten novel dyes studied exhibit significant potential for use in DSSCs, and the theoretical methods employed here offer a reliable framework for predicting the properties of other materials. This approach can guide the development of new materials designed to improve the performance of DSSCs.

Using a regioselectivity descriptor known as Fukui indices, this theoretical study examines the reactivity of cycloaddition processes of benzamide (PhCONH2) and chlorocarbonylsulfenyl chloride (ClCOSCl) at the level of base 6-311 G (d. p) by use of the DFT approach. Therefore, the attack of the sulfur atom on nitrogen and carbon on oxygen is kinetically more preferred than the assault of the sulfur atom on oxygen and carbon on nitrogen, as we have observed from our study. The electrophilic Δω difference between chlorocarbonylsulfenyl chloride and benzamide is 1.3726 eV. This indicates that the reaction under investigation has a polar nature (Δω > 1). on oxygen and carbon on nitrogen, as we have observed from our study. We have also studied the stereoselectivity and feasibility of these reactions from a thermodynamic and orbital point of view. The transition states of this reaction have been determined.

Oxadiazoles, a class of nitrogen-containing heterocycles, exhibit diverse applications in pharmaceuticals, industry, and other fields. This study employs Density Functional Theory (DFT) to investigate the structural, electronic, and spectroscopic properties of four oxadiazole isomers. The B3LYP functional and the 6-311G(d,p) basis set were used for calculations. Frontier orbital energies, energy gap, chemical reactivity descriptors, dipole moment, and thermodynamic properties were computed. Additionally, IR and UV spectra were analyzed. The results indicate significant variations in electronic and thermodynamic properties among the isomers. Isomer 4 demonstrated the highest stability and electrophilicity. The calculated IR and UV spectra were compared with available experimental and theoretical data. The study provides valuable insights into the structural and reactivity trends within the oxadiazole family, contributing to a deeper understanding of their potential applications.

This study focuses on the efficient synthesis of series of substituted 4-amino-6-(1H-benzimidazol-2-ylsulfanyl) benzene-1,3-dicarbonitrile derivatives synthesized from aldehydes, propanedinitrile, substituted thiols and catalyzed by ZnO nanoparticles (ZnONPs). All the synthesized compounds have been characterized using different spectroscopic techniques such as FT-IR, ¹H-NMR, C¹³-NMR and Mass. The compounds were evaluated for potential pharmacological applications, including antimicrobial, α-amylase inhibitory and anticancer activities. Computational calculations, DFT, in-silico molecular docking, and ADME-toxicologystudies were performed. ADMET studies indicated that all synthesized compounds adhered to Rule of five with good bioavailability. This research underscores the promising pharmacological prospects of the synthesized newbenzimidazole derivatives.

Methyl α-D-mannopyranoside (MAM) is a naturally occurring carbohydrate derivative that has gained attention in drug discovery due to its potential therapeutic applications, particularly as an antifungal agent. In this study, we employed a computational approach to investigate the interactions between MAM and two Candida albicans antifungal proteins, 1IYL and 1AI9, through molecular docking simulations. Furthermore, we performed a PASS (Prediction of Activity Spectra for Substances) analysis to predict MAM potential biological activities, explored the pharmacokinetic properties and ADMET (absorption, distribution, metabolism, excretion, and toxicity) profiles, and optimized the MAM using the density functional theory (DFT) method. The molecular docking results revealed favorable binding interactions between MAM and the active sites of the 1IYL and 1AI9 proteins, suggesting potential antifungal activity. Additionally, the ADMET profiles indicated low toxicity and suitable drug-like properties, such as moderate metabolic stability and minimal risk of adverse effects. Furthermore, DFT optimization was performed to investigate the molecular geometry and electronic properties of MAM. The optimization results provided valuable information on the stability and reactivity of MAM, enabling a better understanding of its chemical behavior and potential modifications for enhanced activity. Finally, PASS prediction was employed to evaluate MAM's potential biological activities beyond its antifungal properties. The analysis revealed several potential activities, including antibacterial, antiviral, and immunomodulatory effects, expanding the scope for future research and therapeutic applications. In conclusion, this computational study sheds light on the molecular interactions, pharmacokinetic properties, ADMET profiles, DFT optimization, and PASSES predictions of MAM. These findings highlight the potential of MAM as a promising antifungal agent with favorable pharmacological properties.

In this work, two organic materials as dyes, namely, methylene blue (MB) and methyl red (MR), have been proposed to play the role of the electron donor in organic photovoltaic (OPV) cells. We use the PCBM as a well-known electron acceptor. The density functional theory (DFT) method has been used to determine the electrostatic potential and the frontier molecular orbitals (FMO), of the methylene blue (MB) and the methyl red (MR) compounds. Nonlinear optical (NLO) descriptors have been determined for the two compounds. The potential energy surface analysis has been performed by the DFT method using the exchange and correlation of Becke, Lee, Yang, and Parr Gradient Corrected Functional (B3LYP) with the standard 6-31G(d) base. We have performed another theoretical study using quantum time-dependent density functional theory (TD-DFT) on both MB and MR as organic dyes to determine their UV-Vis spectra. The results of the energy gap, chemical hardness, dipole moment, and hyperpolarizability show that MB may be chemically more reactive Than MR. The present work has proposed a bilayer organic photovoltaic (OPV) cell to contribute to the valorization of the two dyes as solar materials. The developed photovoltaic cell project has used electrical and energetic parameters that can describe the OPV cell based on ([MB or MR]: PCBM). Open-circuit voltage (Voc), excitation energy, and oscillator strength have been theoretically determined. The results of the present work showed a remarkably high open circuit voltage, especially in the case of methyl red (1.55 V) more than in the case of the methylene blue (0.84 V) so that both of the two dyes can be a good candidate for organic solar cells.