Frontier Molecular Orbital Analysis Research Articles

Photophysical properties of four-membered BN3 heterocyclic compounds: theoretical insights.

Understanding the photochemistry of boron nitrogen (BN)-containing compounds is an important aspect to enhance the various optical and electronic applications. In this work, we have explored the structure, bonding, reactivity, electronic absorption (UV-Vis), and light harvesting efficiency (LHE) of a series of BN3 ring and open-chain systems. The frontier molecular orbitals (FMO) analysis found that ring systems have a low HOMO-LUMO energy gap as compared to the open-chain systems which insinuates the feasibility of ring systems in the optoelectronic materials. Also, the molecular electrostatic potential (MEP) maps have been computed to pursue the electrophilic and nucleophilic sites available at the surface of the compound. Interestingly, we have found that the open-chain compounds show more molecular charge distribution range rather than the ring compounds. The investigation of photophysical properties showed that the UV-Vis absorption significantly red-shifted in BN3 ring systems as compared to open-chain counterparts. Furthermore, light harvesting efficiency (LHE) was also found higher in the ring systems as compared to the BN3 open-chain systems. Moreover, the computed structural parameters are found well corroborated with the available X-ray data. Structures of all compounds were optimized by using density functional theory (DFT) method, with M06-2X/6-31G(d,p) level. All the calculations in this work are carried out in Gaussian 16 program package. GaussView6.1 software was used for the modeling of initial geometries and for the plotting of MEP plots. To account the solvent effect on geometries the polarized continuum model (PCM) was used and tetrahydrofuran (THF) taken as solvent. The NBO6.0 program (incorporated in G16 software) was used for the exploration of bonding nature and stabilization energies of B-N bond. The absorption spectra were simulated by using ORCA 4.2 program.

Triquinoxalinylene and benzoquinone based covalent organic framework as robust material for mitigation of environmental pollutants-A theoretical approach

The physisorption of pollutant gases (NH3, HCN, H2S and PH3) on TQBQ-COF has been explored using DFT calculations. The strength and nature of interactions were determined through interaction energy, non-Covalent interactions- Reduced Density Gradient (NCI-RDG) plots, Frontier Molecular Orbital (FMO), Natural bond orbital (NBO), Electron Density Difference (EDD) and Quantum Theory of Atoms In Molecule (QTAIM) analysis. The optimized geometries and interaction energy calculations revealed that the analytes interacted with Oxygen and Nitrogen atoms of TQBQ-COF leading to adsorption energy ranging from −10.66 to −5.85 kcal/mol. The values of recovery time were in agreement to that of interaction energy and decreased with the increase in temperature. The NCI-RDG plots and QTAIM analysis revealed the presence of weak van der Waals forces in all complexes and partial covalent character in H2S@TQBQ-COF. Charge transfer study (employing NBO and EDD analysis) depicted the transfer of charge from surface to analytes. The study of HOMO-LUMO energy gap in FMO analysis depicted the high sensitivity of TQBQ-COF for H2S and NH3 compared to HCN and PH3 due to significant lowering of HOMO-LUMO energy gap upon the adsorption of H2S and NH3 on TQBQ-COF.

A stereoselective nontraditional Heck reaction mechanism: Origins of enantioselectivity and diastereoselectivity

Nontraditional Heck-type reactions of C = heteroatomic variants have been a great challenge. Herein, we computationally investigate a nontraditional stereoselective Heck mechanism regarding hydrazone C = N-NH2 by using density functional theory (DFT) methods. Calculations indicate that the total potential barrier of the conversion is 25.6 kcal/mol, which is reasonable to be crossed under the current reaction conditions. Unlike C = C π-bonds, the coordination of C = N with transition metal palladium into a η1-complex is confirmed. A larger π-bond insertion barrier for C = N is required, which is rationalized by frontier molecular orbital (FMO) analysis with a wider LUMO-HOMO energy gap. π-bond insertion is the enantioselectivity determining step of the strategy and that the pathway toward the R-isomer exhibits a much lower energy barrier (24.2 vs 40.1 kcal/mol). π-bond insertion is also the diastereoselective control step with using DBBP ligands. Non-covalent interaction (NCI) analysis confirms that greater spatial hindrance is responsible for the stereoselectivity of the protocol. Meanwhile, calculations show that using an acid-promoted tactic can effectively improve the in situ production of hydrazone and significantly reduce the energy barrier.

Solvation impact on the geometry and electrical properties of Flufenoxuron: A topological and spectral insight by DFT approach

The present study pursues a quantum computational audit on the structural, electronic traits, vibrational (FT-IR, FT-Raman), topological aspects and bioactivity analysis of Flufenoxuron, a benzoyl urea derivative deploying Density Functional Theory (DFT). In vacuum, solvent modes, the molecular characteristics of the title compound were gauged. Electronegative alternatives in the aromatic rings considerably permute the geometry. According to Natural Bond Orbital (NBO) study, notable hydrogen bonding that significantly stabilises the system results from electron transfer from the host to the guest. Vibration mode allocations were performed based on PED (Potential Energy Distribution) using normal coordinate analysis which substantiates N-H⋯O hydrogen bonding. The reactivity of the compound is significantly appraised by the Solvent effect as evinced from the frontier molecular orbital analysis (FMO) through an elevated electrophilicity index descriptor value. Molecular Electrostatic Potential (MEP) highlights the electrophilic nature of the electronegative atoms in the molecule. The docking analysis identified the chemical's predominant binding site with the receptor target and predicted its inhibitory activity against the Pseudomonas aeruginosa bacterial strain that has a leading binding affinity.

A theoretical investigation on hirshfeld surface, IR., UV–Vis, 1H and 13C NMR spectra, nonlinear optical properties, and in silico molecular docking of an organometallic compound: Dibromobis(l-proline)zinc(II)

This study presents quantum chemical computations and in silico molecular docking for a Zn(II) complex from the proline derivative family, with the chemical formula C10H18Br2N2O4Zn, while the synthesis involved a mixture of ZnBr2 and l-proline, which was heated at 40–45 °C for 5 h. The mixture was filtered, dried, and recrystallised to increase purity using methanol. The calculations utilised density functional theory (DFT) with the B3LYP functional and a combined basis set of 6–311++G(d,p) and LanL2DZ. The molecular structure was optimised, and based on this optimised structure, IR, UV–Vis, and NMR spectra were calculated. The frontier molecular orbitals (FMOs) analysis was conducted to obtain various chemical activity parameters associated with the energy gap.Additionally, properties such as dipole moment and first and second hyperpolarizability were investigated and analysed using the B3LYP level of theory within the DFT framework. Furthermore, the title compound was subjected to molecular docking with SARS-CoV-2 protein receptors to explore ligand–protein interactions. The docking results revealed a binding energy of −6.2 kcal/mol, suggesting that the title compound has potential as a candidate against the main protease of SARS-CoV-2.

DFT, Molecular Docking, Energy‐Framework, In‐silico ADME Analysis of 2,6‐Diamino‐4‐chloropyrimidine–succinic Acid (2/1)

AbstractComputational modelling and simulation have made it possible to considerably advance in the exploration of conformational and dynamical features of the desired compound. It not only assists in the interpretation of the experimental result, but also to provide insights about the internal motions of the molecule at the atomic level. In this work, Density Functional Theory calculations are performed to replicate the experimental electronic structure of 2C4H5ClN4.C4H6O4, and its nature is discussed in detail. The B3LYP/6‐311++G(d,p) basis set applied to evaluate the optimal structure characteristics resulted in revealing the corresponding chemical, physical, and biological properties of the molecule. The energy exchange between the contributor and receiver are examined by Natural Bond Orbital analysis. Based on frontier molecular orbitals analysis, the obtained minimum energy gap (0.199 eV) value ensures the stability of the title compound. The molecular electrostatic potential mapping predicts the electrophilic and nucleophilic charge distributions on the molecule. The 3D topology of the crystal packing is analyzed and interpreted via the energy‐framework simulation studies using CystalExplorer software. Through the In‐silico‐ADME calculations, the drug‐likeness and physicochemical properties of the molecule is predicted. Furthermore, the molecular docking studies are used to determine the bioactivity and anti‐diabetic properties of the title compound.

Solvent-solute interaction, thermodynamic behaviour, structural, chemical and anti-cancer biological properties of 3(2H)-furanone derivatives

In this work, the structures, reactivities, and electronic and biological properties of the 3(2H)-furanone derivatives, 2-hydroxy-2,5-diphenyl-4-(phenylamino)furan-3(2H)-one (HDPF), 2-methoxy-2,4,5-triphenylfuran-3(2H)-one (MTPF), 3-oxo-2,4,5-triphenyl-2,3-dihydrofuran-2-yl acetate (OTDF), and 2-chloro-2,4,5-triphenylfuran-3(2H)-one (CTPF), are explored via theoretical investigations using DFT (Density Functional Theory) techniques as the main tools for the study. The DFT studies include geometry optimisation, FMO (Frontier Molecular Orbital) analysis, theoretical UV studies, molecular electrostatic potential (MEP) investigations, non-linear optical (NLO) analyses, and the evaluation of thermodynamic parameters. Multiwfn 3.8 software is utilised to conduct the topological analyses. The ADME (Absorption, Distribution, Metabolism, Excretion) profiles are produced with the SwissADME online tool. The target proteins, MCL-1 (Myeloid cell leukemia-1), BCL-2 (B-cell lymphoma-2), and myeloblastin, are docked with the title molecules using AutoDock 1.5.6.

Conjugation-modulated optoelectronic and anti-corrosion properties of pyrrole oligomer: Insights from DFT/TD-DFT analysis

To investigate the influence of π-conjugation on optical properties, models of Pyrrole oligomers with varying π-bridge lengths, ranging from 1 to 5, were constructed. The π-bridge plays a crucial role in tuning and modulating the optoelectronic characteristics of these molecules. By employing FMO (Frontier Molecular Orbital) analysis, the band gap values were determined. Notably, the pyrrole oligomer with a 1π-bridge exhibited a higher band gap (2.68 eV) compared to the 5π-bridge variant (1.53 eV). Moreover, the calculated hyperpolarizability (β°) values exhibited a substantial increase from 37 esu to 1876 esu as the extent of π-conjugation was augmented. This suggests that enhanced π-conjugation promotes greater nonlinear optical properties. Further analysis revealed that the pyrrole oligomer with 5π-bridges displayed maximal absorption at a longer wavelength, specifically 1024 nm. This information provides valuable insights into the absorption characteristics of these molecules. Additionally, the NBO (Natural Bond Orbital) analysis successfully captured the stable donor-acceptor interactions responsible for the ground state stabilization observed in pyrrole oligomers. On the other hand, the QTAIM (Quantum Theory of Atoms in Molecules) analysis provided detailed information regarding weak interactions, such as hydrogen bonding, which contribute to the stabilization of the modeled monomers. In summary, the creation of Pyrrole oligomer models with varying π-bridge lengths facilitated the evaluation of the impact of π-conjugation on the optical properties. The findings indicate that increasing the π-conjugation leads to a decrease in the band gap, an increase in hyperpolarizability, and absorption at longer wavelengths. Additionally, the stability of the ground state and the nature of weak interactions were elucidated through NBO and QTAIM analyses, respectively.

Justicia adhatoda L. vasicin and vasicinone as bioactive phytochemical compounds: Isolation, characterization, and computational studies

Justicia adhatoda L. has wide applications in traditional and modern medicine. Its major potency is due to the presence of two alkaloids viz. Vasicine and Vasicinone. In industry, the demand for both marker compounds as well as quality Justicia adhatoda L. material is very high. The isolation of bioactive phytochemical compounds for the development of an in-house phytochemical reference standard library to verify quality control is of prime demand for an analytical chemist. For these reasons, the objective of the present study was to isolate two members of the alkaloids Vasicine and Vasicinone marker compounds from Justicia adhatoda L. Extraction was carried out by using a cold percolation method in a successive manner by increasing the order of polarity of the solvents from petroleum-ether to ethanol. Isolation was achieved for the above said two maker compounds by using separation, purification though column chromatography on silica-gel using mobile phase chloroform, and ethanol. Characterization of the isolated compounds was carried out by UV–VIS, IR, 1H NMR, 13C NMR and mass spectroscopy techniques. The isolated and purified solid compounds were confirmed as Vasicine and Vasicinone by comparison and co-relating with observed spectroscopy data and literature data. The compounds had a good to high amount of yield (0.4 % to 0.63 %) with high purity (98–100 %) through HPL. Lastly, frontier molecular orbital analysis (HOMO and LUMO), and global descriptive parameters (such as chemical potential, electronegativity, hardness, softness, etc.) were analyzed using computational approaches. Results revealed a good correlation with experimental data except for a few alternations in 1H NMR data.

Hirshfeld Surface Analysis and Density Functional Theory Calculations of 2-Benzyloxy-1,2,4-triazolo[1,5-a] quinazolin-5(4H)-one: A Comprehensive Study on Crystal Structure, Intermolecular Interactions, and Electronic Properties

This study employs a comprehensive computational analysis of the 2-benzyloxy-1,2,4-triazolo[1,5-a] quinazolin-5(4H)-one (ID code: CCDC 834498) to explore its intermolecular interactions, surface characteristics, and crystal structure. Utilizing the Hirshfeld surface technique and Crystal Explorer 17.5, the study maps the Hirshfeld surfaces for a detailed understanding of atom pair close contacts and interaction types. The study also investigates the compound’s electronic and optical characteristics using Frontier Molecular Orbital (FMO) analysis and Global Reactivity Parameters (GRPs). The compound is identified as electron-rich with strong electron-donating and accepting potential, indicating its reactivity and stability. Its band gap suggests Nonlinear Optical (NLO) attributes. The Molecular Electrostatic Potential (MEP) map reveals charge distribution across the compound’s surface. The computational methods’ reliability is validated by the low Mean Absolute Error (MAE) and Mean Squared Error (MSE) in the comparison of experimental and theoretical bond lengths and angles.

QSAR, DFT studies, docking molecular and simulation dynamic molecular of 2-styrylquinoline derivatives through their anticancer activity

In this study, a 2D-QSAR (quantitative structure–activity relationship) was performed on 54 new 2-Styrylquinoline derivatives as anticancer substances capable of inhibiting the p53 protein in the cell HCT116++. The 54 2-Styrylquinoline derivatives was calculated applying DFT 6-31G basis to calculate Quantum descriptors, using MM2 for: Topological, Physico-chemical, Geometrical and Constitutional. The study was carried out by performing multiple linear regression (R2 = 0.90), the QSAR model achieved was tested by artificial neural networks method, which is showed high predictability (R2ANN = 0.89). A DFT study was performed to determine the reactivity of the 2-Styrylquinoline derivatives using frontier molecular orbital analysis and analysis of the molecular electrostatic potential (MEP). Derivatives of 2–4 Styrylquinoline are studied for their synthetic accessibility and their similarity to drug. The obtained results show that all the evaluated compounds have similar properties to drug and are accessible to synthesize.A molecular docking analysis was performed for three compounds: 14, 34, and 54, having various reactivities against the p53 HCT116++ protein (identified by PDB ID: 2GEQ). The results showed strong interactions between the three ligands and the 2GEQ protein, the amino acids HIS 176, SER A180, PRO A188 and ARG A178 are the most active sites of the 2GEQ protein, and based on these result we performed a molecular dynamics simulation to evaluate the stability of our complexes. The MD demonstrates the thermodynamic stability of select compounds during 40 and 100 ns, with all three complexes showing a high level of structural stability.

Theoretical investigations on structural, spectral, NBO, NLO and topology exploration (AIM, ELF, LOL, RDG) of piperazine-2,5-dione oxalic acid monohydrate

The present work investigates the structural stability and nonlinear optical (NLO) activity of piperazine-2,5‑dione oxalic acid monohydrate (PDOAH) using quantum chemical computational techniques. The optimized molecular structure and vibrational wavenumbers of the PDOAH molecule are determined by density functional theory (DFT) with B3LYP/6–311G(d,p) basis set. The vibrational wavenumbers, IR intensities, Raman activities and their corresponding PED values are obtained and analysed. Natural bond orbital (NBO) analysis is carried out to determine inter and intramolecular charge transfer interaction, intermolecular hydrogen bonding and hyperconjugative interactions that stabilize the structure. The charge transfer interaction, electrophilic, nucleophilic and chemical reactivity sites are identified with the aid of molecular electrostatic potential (MEP) and frontier molecular orbital (FMO) analysis. The TD-DFT method is utilized in UV–Vis spectral analysis for the molecule in the water solvent. RDG and IRI analysis is performed to spot the van der Waals interaction and steric effect within the molecule. The Hirshfeld surface analysis is carried out to scrutinize the intermolecular interactions. The nonlinear optical (NLO) parameters of PDOAH are evaluated through DFT calculation and compared with that of urea.

Investigational, computational explorations on betanin, lycopene, cyanidin, and peonidin organic photo sensitizers for green energy harvesting

In keeping green energy harvesting as a prime priority and lowering the cost per watt, three potential red-colored organic photosensitizers were separated and employed for proficient titanium dioxide (TiO2) photoanodes. In a prime attempt, Rivina Humilis fruit extract (Betanin) was used for natural dye-sensitized solar cells (NDSSCs). The Prunus cerasus fruits and Solanum lycopersicum fruits (Lycopene) extracts were also successfully employed to fabricate NDSSCs. Cyanidin, Peonidin, and Lycopene are the prominent colorants existent in Prunus cerasus, and their optimized molecular structure was premeditated via Density functional theory. Their thermochemistry and associated physical parameters, Frontier molecular orbitals (FMOs) analyses, theoretical ultraviolet (UV) – visible exploration, and molecular electrostatic potential reactivity analysis were studied. Microwave-assisted sol–gel practice has yielded pure anatase TiO2 nanoparticles (NPs). The pure, red dye-sensitized TiO2 NPs endured needed studies. Environment-friendly, cost-per-watt effective NDSSCs were accomplished by expanding three red-colored organic photoanodes. Among three photosensitizers, Rivina Humilis fruits showed 1.35%, followed by Prunus cerasus at 1.27 % and slightest by Solanum lycopersicum at 0.82%. And, owing to the above performances, these NDSSCs have the potential to be employed in low-power indoor energy harvesting.

Spectroscopic, quantum chemical investigation and molecular docking studies on N-(2-benzoylamino) phenyl benzamide: A novel SARS-CoV-2 drug.

The present work describes the structural and spectral properties of N-(2-benzoylamino) phenyl benzamide (NBPB). The geometrical parameters of NBPB molecule such as bond lengths, bond angles and dihedral angles are calculated and compared with experimental values. The assigned vibrational wave numbers are in good agreement with the experimental FTIR and FT Raman spectra. The vibrational frequency of C=O stretching was downshifted to a lower wave number (red shift) due to mesomeric effect. The UV-Vis spectrum of the title compound was simulated and validated experimentally. The energy gap and charge transfer interaction of the title molecule were studied using frontier molecular orbital analysis. The electrophilic and nucleophilic reactivity sites of NBPB were investigated through the analysis of the molecular electrostatic potential surface and the Fukui function. An assessment of the intramolecular stabilization interactions of the molecule was performed using natural bond orbital analysis. The drug-likeness parameter was calculated. To investigate the inhibitory potential of the molecule, molecular docking analysis was conducted against SARS-CoV-2 proteins, revealing its capability to serve as a novel inhibitor against SARS-CoV-2. The high binding affinity of NBPB molecule was due to the presence of hydrogen bonds along with different hydrophobic interactions between the drug and the SARS-CoV-2 protein receptor. Hence, the title molecule is identified to be a potential candidate for SARS-CoV-2.

Rational design of co-ordination compounds in combination of bipyridine type of ligands and group 7 metal (M = Mn, Re) for photoCORM: a DFT study.

A large number of manganese and rhenium tricarbonyl complexes are known in literature along with various applications in different fields. CO-releasing molecules (CORMs) got recent research attention because CO can act as a prodrug for different diseases. CORMs offer the promising prospect of a safe and controllable amount of CO release. In this research work, we have explored the electronic properties of compounds such as bipyridine-related [Mn(CO)3] and [Re(CO)3] and we have compared the electronic properties of both manganese and rhenium tricarbonyl complexes in the light of carbon monoxide releasing tendency. The chosen Mn and Re metals have enough possibility to vary or play with ligands and design a new and novel CORM molecule. In this context, we have taken a range of 4,4'-disubstituted 2,2' bipyridyl ligands (Rbpy, where R = NH2, tBu, OCH3, H, CF3, CN, NO2) to investigate CO's liberation ability to identify and study such molecules. The calculated absorbance of designed complexes (1-14) shows visible/near-IR region (350-850 nm). The HOMO-LUMO energy gap of 7 (ΔE=2.40 eV) complex and for complex 14 (ΔE=2.28 eV) which is lesser in all complexes but the MLCT percentage is greater in Mn tricarbonyl complexes in comparison to Re tricarbonyl complexes. The calculated results of the FMO approach revealed that complex 7 and 14 have the lowest energy gap which is also in good agreement with DOSs and TDM results. The theoretically calculated results revealed that the both Mn and Re tricarbonyl complexes have a tendency for labialization of CO, but Mn tricarbonyl complexes are more prone to CO release because they have higher MLCT percentage. In this research work, we have performed density functional theory (DFT) calculations to explore the physical properties of compounds such as bipyridine-related [Mn(CO)3] and [Re(CO)3] and we have compared the physical properties of both manganese and rhenium tricarbonyl complexes in the light of carbon monoxide releasing tendency. DFT-based calculations were performed by using B3LYP/LANL2DZ basis set followed by acetonitrile solvent using the conductor-like polarizable continuum model (CPCM) for different calculations. Various geometrical calculations were performed using the Gaussian16 suite of programs and the output results obtained from Gaussian16 were visualized using GaussView 5.0.16. The same level of theory was used for various calculations, including frontier molecular orbital (FMO) analysis, metal to ligand charge transfer (MLCT), density of state (DOS) calculations, and transition density of matrix (TDM) calculations. For specific calculations, GaussSum 2.2 software package was used to calculate the density of states, and the Multiwfn 3.8 program was used to analyze the transition density matrix, which is presented using heat maps for both electrons and holes.

Fine-Tuning of the Electronic and Optical Properties of Dodecabenzocoronene through Boron and Nitrogen Doping: A DFT Insight

Nanographene provides a wide range of possibilities in graphene engineering for future applications due to the higher degrees of configurational freedom with the electronic parameters that may also be continuous or discrete, depending on the intended application. Therefore, the optical and electronic properties of nanographene are of substantial technological interest. Moreover, doping of graphene with heteroatoms (B, P, N, and S, etc.) alters their chemical and electronic characteristics which are suitable for the economical construction of optoelectronic devices. Herein, geometric, electronic, and optical properties of nanographene are evaluated as a function of the nature and position of dopant. Three different nanographene including coronene, hexabenzocoronene (HBC), and dodecabenzocoronene (DBC) are considered for doping (N and B as dopants) in this study with the key focus on DBC-doped systems. For any dopant number, all possible dopant sites are studied except edge position in order to avoid the edge effect. Frontier molecular orbital (FMO) analysis is performed to evaluate the perturbations in electronic characteristics of doped nanographene. A decrease in energy gap is seen for all doped systems. Natural bond orbital (NBO) analysis indicates that doping of boron (B) and nitrogen (N) results in variation in distribution of charges over the nanographene surfaces. The density of states (DOS) analysis reveals that Fermi level ([Formula: see text] is shifted for all B- and N-doped systems. The UV-visible (UV-Vis) absorption spectra are computed to evaluate the changes in the intensity and maximum adsorption wavelength ([Formula: see text] in all doped DBC. Various chemical reactivity descriptors are also evaluated which reveal the degree of stability and chemical reactivity of doped systems. The results indicate that multiple B and N atoms doping offers a new possibility for fine-tuning of electronic and optical properties of nanographene at atomic level, thus providing guidance in development of future advanced optoelectronic devices.

Influence of azacycle donor moieties on the photovoltaic properties of benzo[c][1,2,5]thiadiazole based organic systems: a DFT study

Fullerene free organic chromophores are widely utilized to improve the efficacy of photovoltaic materials. Herein, we designed D-π-A-π-D form chromophores (TAZD1-TAZD5) via end-capped redistribution of donor moieties by keeping the same π-bridge and central acceptor unit for organic solar cells (OSCs). To analyze the photovoltaic characteristics of these derivatives, DFT estimations were accomplished at B3LYP/6–311 G (d,p) functional. Different investigations like frontier molecular orbital (FMO), absorption spectra (UV–Vis), density of states (DOS), binding energy (Eb), open circuit voltage (Voc), and transition density matrix (TDMs) were performed to examine the optical, photophysical and electronic characteristics of afore-mentioned chromophores. A suitable band gap (∆E = 2.723–2.659 eV) with larger bathochromic shift (λmax = 554.218–543.261 nm in acetonitrile) was seen in TAZD1-TAZD5. An effective charge transference from donor to acceptor via spacer was observed by FMO analysis which further supported by DOS and TDM. Further, lower binding energy values also supported the higher exciton dissociation and greater CT in TAZD1-TAZD5. Among all the designed chromophores, TAZD5 exhibited the narrowest Egap (2.659 eV) and maximum red-shifted absorption in solvent as well as gas phase i.e. 554.218 nm and 533.219 nm, respectively which perhaps as a result of the phenothiazine-based donor group (MPT). In a nutshell, all the tailored chromophores can be considered as efficient compounds for promising OSCs with a good Voc response, interestingly, TAZD5 is found to be excellent chromophores as compared to all these designed compounds.

Comparison of the binding energies of approved mpox drugs and phytochemicals through molecular docking, molecular dynamics simulation, and ADMET studies: An in silico approach

The mpox (previously monkeypox) outbreak in more than 100 non-endemic countries in 2022 posed a serious global health concern. Mpox is emerging as a global public health threat from a seemingly neglected disease. A42R profilin-like protein from mpox virus (PDB ID: 4QWO) could be a preferred target lead. The binding affinity of commonly used drugs/mAbs (tecovirimat, brincidofovir, cidofovir) for A42R profilin-like protein was examined in silico through molecular docking. Further, the results were compared with those of the phytochemicals curcumin, rutin, and theaflavin. Tecovirimat (−7.31 kcal/mol, IC50 = 4.39 µM) and theaflavin (−6.99 kcal/mol, IC50 = 7.54 µM) had the highest affinities. Molecular dynamics simulation of the theaflavin–4QWO complex was performed to ascertain the stability of ligand–protein interactions in natural charge, molecular electrostatic potential, and frontier molecular orbital analyses. The predicted QSAR and pharmacokinetic properties of all compounds were evaluated to find a suitable candidate for designing and developing new drugs. The evaluated log P values for brincidofovir and tecovirimat were higher than those of the other drugs in the QSAR study. Theaflavin had an impressive log P of 4.77, which hints at its high biological activity. The findings recommend further in vitro experimental validation to develop potential low-cost mpox therapies.

Structural analysis, reactivity descriptors (HOMO-LUMO, ELF, NBO), effect of polar (DMSO, EtOH, H2O) solvation, and libido-enhancing potential of resveratrol by molecular docking

The profound impact of health challenges related to libido, encompassing sexual dysfunction, hormonal imbalances, relationship difficulties, stress, anxiety, depression, and the effects of certain medical conditions or medications, calls for urgent mitigative measures. As a result, this study meticulously explores the compound Resveratrol (Res) to uncover its substantial properties concerning libido enhancement. The compound was optimized using the DFT/ωB97XD/6–311G++(d, p) basis set in different solvents, namely DMSO (dimethyl sulfoxide), ethanol, and water. Notably, the geometry investigation reveals that the structural bond variations can be attributed to factors such as solvent polarity, screening effects, hydrogen bonding, solvation energy, and conformational preferences. Substantially, the Frontier Molecular Orbital (FMO) analysis explored the HOMO values of the compound in different solvents, resulting in 7.59198 eV, 7.5514 eV, and 7.59687 eV for RES_DMSO, RES_EtOH, and RES_H2O, respectively. Correspondingly, their LUMO values were found to be 7.5955 eV, 7.5648 eV, and 7.5982 eV, leading to respective band gaps of 0.0035 eV, 0.0133 eV, and 0.0014eV Remarkably, RES_H2O displayed the smallest energy gap (0.0014 eV) among the interacting compounds, indicating increased conductivity and sensitivity. Furthermore, the natural bond orbital analysis revealed that RES_H2O had the highest permutation energy among the three complexes (376.5 kcal/mol for RES_DMSO, 371.79 kcal/mol for RES_EtOH, and 378.77 kcal/mol for RES_H2O), indicating a stronger interaction between the donor and acceptor orbitals. Finally, the molecular docking studies unveiled a notable difference in binding affinity, with RES exhibiting a greater affinity for 1UDT at -8.1 kcal/mol compared to 1UDU, which demonstrated a binding affinity of -6.6 kcal/mol. Thus, RES has the potential to reverse erectile dysfunction and improve libido by inhibiting the activities of phosphodiesterase (1UDT and 1UDU), ultimately promoting vasodilatory signals from cGMP to the smooth muscles of the penis, leading to enhanced erection. These groundbreaking findings offer promising prospects for the development of new and effective drugs to combat various medical conditions.

Role of Delocalization, Asymmetric Distribution of π-Electrons and Elongated Conjugation System for Enhancement of NLO Response of Open Form of Spiropyran-Based Thermochromes.

Switchable nonlinear optical (NLO) materials have widespread applications in electronics and optoelectronics. Thermo-switches generate many times higher NLO responses as compared to photo-switches. Herein, we have investigated the geometric, electronic, and nonlinear optical properties of spiropyranes thermochromes via DFT methods. The stabilities of close and open isomers of selected spiropyranes are investigated through relative energies. Electronic properties are studied through frontier molecular orbitals (FMOs) analysis. The lower HOMO-LUMO energy gap and lower excitation energy are observed for open isomers of spiropyranes, which imparts the large first hyperpolarizability value. The delocalization of π-electrons, asymmetric distribution and elongated conjugation system are dominant factors for high hyperpolarizability values of open isomers. For deep understanding, we also analyzed the frequency-dependent hyperpolarizability and refractive index of considered thermochromes. The NLO response increased significantly with increasing frequency. Among all those compounds, the highest refractive index value is observed for the open isomer of the spiropyran 1 (1.99 × 10-17 cm2/W). Molecular absorption analysis confirmed the electronic excitation in the open isomers compared to closed isomers. The results show that reversible thermochromic compounds act as excellent NLO molecular switches and can be used to design advanced electronics.