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Oil-immersed power transformers generate characteristic gases after failure,Therefore, it is necessary to analyse and monitor the soluble gases in transformer oil samples. In this study, the DFT calculation method was used to study the adsorption properties of H2, CO, C2H2, and C2H4 gases in oil on both intrinsic MoTe2 and Rh-doped MoTe2 films. In order to analyse the adsorption characteristics, this paper first obtains the most stable Rh-doped MoTe2 monolayer model through the modelling and computational analysis of different doping sites, then, the adsorption of these gases on the material surface is studied by analysing adsorption energy, charge transfer, total state density, parting density, energy band structure, differential charge density map, molecular front orbital and desorption time, and finally concludes that Rh-MoTe2 monolayer film is the ideal material for hydrogen sensing elements, due to the extremely long desorption time of CO gas, indicating that CO gas is hard to desorption on the surface of adsorbent,which shows that this process has played a certain role in promoting CO removal. Highlights Study focused on gas adsorption using DFT: Rh-MoTe2 ideal for hydrogen sensing and effective for CO removal, intrinsic MoTe2 ineffective and required metal doping. Rh doping enhanced conductivity and gas adsorption capacity in MoTe2. Rh-MoTe2 was suitable for detecting H2, C2H2, and C2H4 gases. Desorption times vary with temperature, with CO removal particularly effective at higher temperatures. Findings suggest potential applications for Rh-MoTe2 in gas sensing and removal. [ABSTRACT FROM AUTHOR]

Lately, the significance of employing nanostructured materials for extracting organic solvents from various mediums has grown in different industries. This includes the development of innovative and versatile nano adsorbents. Computational methods, particularly those utilising dispersion corrected DFT approach, have proven to be powerful tools for investigating the nature of interactions and exploring molecular systems at the atomic level. In order to thoroughly investigate how Eriochrome Black T molecules cling to an o-B2N2 monolayer, we used the dispersion corrected DFT approach in this study. As part of our research, we looked at the fundamental causes of molecular scale experimental results. We used techniques including charge transfer, density of states, and molecular orbitals to investigate a variety of aspects, including energy and electrical elements. We also investigated the relationship between the sensor response (R) and the HOMO-LUMO energy gap. Particularly noteworthy were the o-B2N2 monolayer and EBT, both of which demonstrated significant chemisorption with an adsorption energy (Ead) of −1.11 eV. The conductivity of these devices significantly increased as EBT adsorption neared completion, demonstrating the potential of the o-B2N2 monolayer as a reliable electrical EBT sensor. Moreover, at 698 K, the projected recovery time for the sensor stands at 580 s. [ABSTRACT FROM AUTHOR]

Phytochemicals are now increasingly exploited as remedial agents for the management of diabetes due to side effects attributable to commercial antidiabetic agents. This study investigated the structural and molecular mechanisms by which betulinic acid exhibits its antidiabetic effect via in vitro and computational techniques. In vitro antidiabetic potential was analysed via on α-amylase, α-glucosidase, pancreatic lipase and α-chymotrypsin inhibitory assays. Its structural and molecular inhibitory mechanisms were investigated using Density Functional Theory (DFT) analysis, molecular docking and molecular dynamics (MD) simulation. Betulinic acid significantly (p < 0.05) inhibited α-amylase, α-glucosidase, pancreatic lipase and α-chymotrypsin enzymes with IC50 of 70.02 μg/mL, 0.27 μg/mL, 1.70 μg/mL and 8.44 μg/mL, respectively. According to DFT studies, betulinic acid possesses similar reaction in gaseous phase and water due to close values observed for highest occupied molecular orbital (HOMO) and lowest occupied molecular orbital (LUMO) and the chemical descriptors. The dipole moment indicates that betulinic acid has high polarity. Molecular electrostatic potential surface revealed the electrophilic and nucleophilic attack-prone atoms of the molecule. Molecular dynamic studies revealed a stable complex between betulinic acid and α-amylase, α-glucosidase, pancreatic lipase and α-chymotrypsin. The study elucidated the potent antidiabetic properties of betulinic acid by revealing its conformational inhibitory mode of action on enzymes involved in the onset of diabetes. [ABSTRACT FROM AUTHOR]

This study aims to analyze the molecular orbital parameters of flaxseed oil (linum usitatissimum) and to measure the AC breakdown voltages at different electrode gaps with various rate of rises. AC breakdown voltages of flaxseed oil are measured at 1.0 and 2.5 mm electrode settings with 0.5 kV/s, 2.0 kV/s and 3.0 kV/s rate of rises, adhering to IEC and IEEE standards. UV-VIS (Ultraviolet–Visible) and FT-IR (Fourier Transform-Infrared) measurement tests carried out after breakdown voltage measurements reveals that the molecular structure of the oil remains stable against electrical discharges. The compounds of flaxseed oil are analyzed using GC-MS and it is determined that the oil mainly consists of seven triglycerides in accordance with the literature. In order to better understand the electrical behavior of these triglycerides, molecular orbital properties such as ionization potential, electron affinity and electron energy gap are analyzed employing Density Functional Theory (DFT) using B3LYP/6-311 + G(d,p) and B3PW91/6-311 + G(d,p) basis sets. The advantages of flaxseed oil such as AC dielectric strength, stability against breakdown mechanism, homogeneous molecular electrical characteristics of its compounds and antioxidant content make this oil as one of the potential natural ester alternatives to mineral oils in the power system industry. [ABSTRACT FROM AUTHOR]

'In this study, we employed density functional theory (DFT)/B3LYP method with a 6-311++G(d,p) basis set to analyze the infrared and UV spectra of a carboxylate-appended (2-pyridyl)alkylamine ligand. The FT-IR spectra were recorded within the range of 4000–500 cm-1. Geometrical parameters, energies, and wavenumbers were determined, and the fundamental vibrations were assigned based on the potential energy distribution (PED) of the vibrational modes. The UV spectrum of the compound was measured in various solvents, namely DMSO, CHCl3, and CH3OH. The 1H-NMR shifts were estimated using the GIAO method, and the results were compared to experimental spectra. To further investigate the electronic properties, including excitation energies, absorption wavelengths, and highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) energies, we employed the DFT/B3LYP approach. The degree of electron localization was assessed through analysis of the ELF diagram. Additionally, a molecular electrostatic potential (MEP) was generated, and a 3-D color representation was utilized to visualize reactive sites. Lastly, a biological study involving molecular docking was conducted using six different receptors in order to identify optimal ligand-protein interactions and assess drug similarities.' [ABSTRACT FROM AUTHOR]

We investigate the relative stability of increasingly large helicenes at the CCSD(T) level via the high-level G4(MP2) thermochemical protocol. The relative energies of [n]helicenes (n = 4–9) are obtained via the following reaction: [n]helicene + benzene → [n + 1]helicene + ethene. This reaction conserves the number of sp2-hybridized carbons, the number of aromatic rings, and the helical structures on the two sides of the reaction. We show that the reaction energy converges to an asymptotic value of ΔH298 = + 22.4 kJ/mol for increasingly large helicenes. For comparison, for [n]acenes, the same reaction converges to a much higher asymptotic reaction enthalpy of ΔH298 = + 56.8 kJ/mol. This difference between the two asymptotic reaction enthalpies sheds light on the relative thermodynamic stability of increasingly large helicenes. We proceed to use the G4(MP2) reaction energies to evaluate the performance of dispersion-corrected density functional theory (DFT) and semiempirical molecular orbital (SMO) methods for the relative energies of [n]helicenes. Nearly all DFT methods perform poorly with root-mean-square deviations (RMSDs) above 10 kJ/mol. The best-performing DFT method, BLYP-D4, attains an RMSD = 5.2 kJ/mol. Surprisingly, the advanced SMO methods, XTB and PM7, outperform the DFT methods and result in RMSDs of 3.0 and 3.1 kJ/mol, respectively. [ABSTRACT FROM AUTHOR]

2-(3-Bromophenyl)-1-(4-morpholinyl)ethanone belongs to one of morpholine derivatives. In this paper, 2-(3-bromophenyl)-1-(4-morpholinyl)ethanone was synthesized by a two-step synthesis method. In order to determine the structure of the target compound, FT-IR,1H NMR,13C NMR and MS were used for detection. Meanwhile, X-ray diffraction was used to detect the single crystal and obtain the crystal structure data of the target compound. The molecular crystal structure was compared with that determined by density functional theory. The frontier molecular orbitals and molecular electrostatic potential energy were used to further study the physical properties of the compounds. [ABSTRACT FROM AUTHOR]

The present work deals with the understanding of the integrated experimental and theoretical study of the molecular structure and vibrational spectra of N-allyl-N-ethylformamide (NAEF). Density functional theory (DFT) calculations were used to study the subject molecule, N-allyl-N-ethylformamide (NAEF), utilising the B3LYP method and the basis set 6-311++G (d,p). Geometrical parameters and the structure of NAEF were computed such that global descriptors and reactive sites were obtained. Frontier's analysis of molecular orbital energy demonstrates that the molecule's charge exchange is considerably high. Non-linear optical properties of N-allyl-N-ethylformamide (NAEF) were computed and compared with the standard material of urea. The vibrational assignments were analysed for the existence of the probable functional groups and tabulated. The thermodynamic functions were computed at different temperatures and listed accordingly. NMR spectroscopy and quantum computational chemistry methods have been employed for the understanding of the structures of NAEF. Moreover, different techniques such as topological analysis and drug-likeness were utilised to determine the structure and other properties of NAEF. The molecular docking study could determine the residue with the highest docking score (lowest binding energy) and the most non-covalent interactions. [ABSTRACT FROM AUTHOR]

The molecular structure of 1-(4-hydroxy-3-methoxyphenyl) ethenone has been optimized, and its various parameters were ascertained, using Density Functional Theory. The molecule's Fourier Transform-Infra Red and Raman spectra are recorded and examined. By comparing the computational and experimental results, molecular structure, bond length, and vibrational band intensity were all interpreted. The Integral Equation Formalism polarizable continuum model's depictions of electronic and Frontier Molecular Orbital solvent interaction investigations are sported to perceive the charge transfer among the atoms of the molecule in eco-green solvents such as water, acetone, and ethanol. The reactivity sites can be studied by locating and charting the electron density on the surface. The compound's hardness, softness, electrophilicity, and ionization potential were all analyzed. The pharmacological effects and intra-molecular hyper conjugative interactions are liable for its molecular stability, as shown by Natural Bond Orbital research. Topological studies, including Electron Localized Function, Localized Orbital Locator, and Reduced density gradient analysis, were performed to locate the compound's bonding area and Vander Waals interactions. Urea was used as a reference compound to examine the substance's non-linear optical characteristics. Total Density of States has investigated the role of molecular orbitals. Drug-likeness, a Ramachandran plot, and molecular docking were also performed to further analyze 1-(4-hydroxy-3-methoxyphenyl) ethanone's biological activity. The docking results lend credence to the idea that the title compound could function as a powerful cancer treatment. [ABSTRACT FROM AUTHOR]

An investigation into the properties of the novel compound with thioether-bridge 2-((4,5-di-p-tolyl-4H-1,2,4-triazol-3-yl)thio)-1-mesitylethanone by use of single-crystal X-ray diffraction (SCXRD), FT-IR, and nuclear magnetic resonance spectroscopy and density functional theory calculations. The X-ray crystallographic data, which reveal the molecular and crystal structure, have been collected in the 2.98–26.27 θ range at 296 K. Then, Hirshfeld surface analyses were performed over the crystal structure and possible hydrogen bondings were indicated. In addition to the determination of the structure, characteristic vibrational modes, chemical shifts (1H and 13C), and theoretical highest occupied molecular orbital–lowest unoccupied molecular orbital and UV analysis in four different solvents were evaluated. The structural and spectral results were compared with the corresponding quantum chemical calculations. The experimental and theoretical (calculated) data exhibited good harmony. Additionally, Natural Bonding Orbital and Mulliken charge analyses were investigated. Then, the molecular docking of the title ligand within the Protein Data Bank: 2IJ5 protein was evaluated according to interaction shapes. Lastly, drug-likeness and ADME features of the title molecule were evaluated. [ABSTRACT FROM AUTHOR]

A pyrazole ring derivative 5-(4-fluorophenyl)-1H pyrazole-3-amine was synthesized. The title compound was characterized by 1H NMR, 13C NMR, MS, FT-IR, and single crystal X-ray diffraction. The optimized molecular crystal structure was determined by B3LYP/6-311 + G(2d, p) functional method and based on density functional theory (DFT) calculation. Hirshfeld surface analysis illustrates the study of non-covalent interactions in the title compound. The molecular electrostatic potential (MEP) and major molecular orbitals (FMOs) of the title compounds were analyzed by computational method. Finally, infrared vibration analysis was performed on the target compound. [ABSTRACT FROM AUTHOR]

An indole compound, tert-butyl 6-chloro-3-(4,4,5,5-tetramethyl-1,3,2- dioxaborolan-2-yl)-1H-indole-1-carboxylate, was synthesized by a simple and efficient three-step substitution reaction. The structure of compounds can not be determined without the most common methods, namely, 1H NMR, 13C NMR, IR, MS. The structure of the target compound was determined by the above methods. Besides, the single crystal was obtained by solvent evaporation method, and the crystal structure data were obtained by means of X-ray diffraction and compared with the molecular crystal structure determined by density functional theory (DFT). Frontier molecular orbitals and molecular electrostatic potential energy are crucial in the study of chemical properties. [ABSTRACT FROM AUTHOR]

The geometry optimization, natural bond orbital analysis, and vibrational analysis of a Schiff base compound N2-(4-Methoxysalicylidene) Arginine Hemihydrate (4MSAH) were carried out using the density functional B3PW91 method with the 6–31 G (d,p) basis set. Natural Bond Orbital (NBO) analysis is carried out to examine the various intra and inter molecular interactions of molecular system. Normal coordinate analysis was carried out to elucidate the vibrational modes and the assignments were made on the potential energy distribution. From the vibrational analysis, it is endorsed that the stretching wave number of hydrogen bond donor COO- and hydrogen bond acceptor NH2+ is shifted due to the interaction. MO (Molecular Orbital) analysis was accomplished to propose the biological activity of the molecule and the impact of the transition of electrons from n→π* was studied using the UV transmittance spectrum. The molecular orbital contributions are studied by using DOS spectral analysis. Topological studies of 4MSAH were conducted utilizing the Electron Localization Function (ELF) and the Local orbital locator (LOL). Hirshfeld surface analysis and reduced density gradient analysis were conducted to investigate distinct covalent and non-covalent interactions. Molecular docking was employed on antifungal proteins to explore protein-ligand interactions and verify the compound's bioactivity. [ABSTRACT FROM AUTHOR]

A ratiometric dual-mode probe NI-SH based on 1,8-Naphthalimide was prepared for H2S detection. When treated with H2S, the fluorescence of NI-SH changes from blue (456 nm) to green (540 nm), and displays significant color variation (colorless to yellow) that can visible to the naked eye. Further investigation shows that the NI-SH has high sensitivity, selectivity, and low detection limit at about 0.2 μM, and with large Stokes shift (84 nm). The intermolecular charge transfer (ICT) response mechanism of NI-SH was further studied by analyzing the distributions of the molecular orbital. Besides, NI-SH exhibits a ratiometric fluorescence response in living Hela cells. [ABSTRACT FROM AUTHOR]

In this study, we synthesized three new polymers, P1–P3, incorporating electron-donating 6,12-dihydro-6,6,12,12-tetraoctyl-indeno[1,2-b]fluorene (IF) and structural isomers of weak and strong electron-accepting 2,5-dioctyl-4,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,3(2H,5H)-dione (IFPPD) or 2,5-bis(2-ethylhexyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (LFPPD), or both the IFPPD and LFPPD units to study the performance of IF-based polymers on non-fullerene acceptor-based organic solar cells (NFA-OSCs). Polymer P1 exhibited absorption from 300 nm to 450 nm with an optical bandgap (Eg) of 2.39 eV, whereas P2 and P3 showed extended absorption up to 700 nm with an Egof 1.76 eV. The determined highest occupied molecular orbital/lowest occupied molecular orbital (HOMO/LUMO) levels for P1–P3 were −5.54 eV/–3.15 eV, −5.40 eV/–3.64 eV, and −5.42 eV/–3.66 eV, respectively. The NFA-OSCs fabricated using P1–P3 as the electron donor and Y6 as the electron acceptor exhibited a maximum power conversion efficiency (PCE) of 0.8%. We also utilized P1–P3 as a co-adsorber and fabricated ternary NFA-OSCs using P1–P3:PM6:Y6 blends. The performance of the ternary devices was lower than that of binary devices made from the PM6:Y6 blend. Herein, we report the preparation of IF-based polymers containing pyrrolopyrroledione derivatives for binary and ternary NFA-OSC applications. [ABSTRACT FROM AUTHOR]

In the present work, we report the experimental and computational investigations of 3-Hydroxy-4-nitrobenzaldehyde (3H4NB) were examined. Comparing observed and simulated vibrational spectra allowed for the identification of characteristic frequencies and the attribution of band names. For the density functional theory (DFT) calculations, the LSDA functional with 6-311 + G(d,p) degree of approximation was used. Furthermore, the same level of theory was used to calculate molecular orbitals such as natural bond orbitals (NBOs) and the HOMO-LUMO energy gap. The condensed Fukui function and the molecular electrostatic potential (MEP) surface were used to determine the relative electrophilicity and nucleophilicity of the current molecule. Intermolecular hydrogen bonding interactions are studied using Hirshfeld surface analysis and fingerprint plots. Molecular docking analysis was used to investigate the compound's biological activities. The hydrogen bond active binding residues and binding energy of a chosen chemical with carcinogenic activity targets were examined. [ABSTRACT FROM AUTHOR]

In this research work, Density Functional Theory based computational analysis on the molecular structure of Divalproex Sodium was carried out in the gas phase. Comprehensive analysis of vibrational spectra, Proton and Carbon Nuclear Magnetic Resonance, and electronic absorption spectrum have been carried out and the findings were compared to those obtained using computational techniques. The electronic transport properties were studied by the Ultraviolet-Visible spectrum obtained in distinct solvents by Time Dependent-Density Functional Theory method. Also, inter and intra-molecular interactions and charge transfer activity within the system were studied by Natural Bond Orbital and Frontier Molecular Orbital analyses. For the Non-Linear Optical profile of the compound, hyperpolarizability calculations were performed. The chemical reactivity of the investigated substance has also been disclosed by reactivity descriptors. The biological assessment through drug-likeness characteristics and molecular docking studies was performed to find the compound as anticonvulsant drugs. Optimized geometrical parameters were computed Vibrational, Electronic, and NMR spectra have been analyzed. Stability and chemical reactivity were studied. Inter/intramolecular interactions have been observed. Pharmacological activities were reported. [ABSTRACT FROM AUTHOR]

The contributions of two energetically highest molecular orbitals to the harmonic emission rate are analysed for a two-component laser field. For diatomic molecules exposed to the elliptically polarised field, the emission from the highest-occupied molecular orbital (HOMO) is dominant for various molecular orientations with respect to the laser field. However, the contribution of the lower molecular orbital (HOMO-1) can become significant or even dominant for some molecular orientations. We introduce the ratio of the coherent over the incoherent sum of the HOMO and HOMO-1 contributions as a quantitative measure of the significance of the particular molecular orbital. Also, the gaseous medium response is different for the left and right elliptically polarised light and the molecular characteristics are imprinted into this difference. Moreover, for the orthogonally polarised two-colour (OTC) laser field the relative contributions of HOMO and HOMO-1 depend to a great extent on the relative phase between the field components. The importance of the HOMO-1 can be assessed by the relative error which is made if the harmonic spectra are obtained only with the HOMO contribution. Finally, we investigate the interference of the contributions of two highest molecular orbitals. We show that, for the OTC field, the destructive interference depends linearly on the intensity of the field components. Also, the interference minima shift towards the higher energies with the increase of the component wavelength. [ABSTRACT FROM AUTHOR]

The ligand 2,2′-(isophthaloylbis(azanediyl))bis(3-phenylpropanoic acid; H2L) was used to build novel metal complexes of Co(II), Ni(II), Fe(III), and Zn(II) metal ions. Elemental analyses, thermal, infrared, mass, electronic spectra, magnetic moments, X-ray diffraction analysis, and conductivity measurements were used to predict the nature of bonding and the stereochemistry of the complexes. The complexes were proposed to have the general formula [M(H2L)(H2O)2]Cln, where M = Co(II), Ni(II), and Zn(II) (n = 2) and Fe(III) (n = 3), based on the elemental analyses data. All of the complexes were electrolytes, according to the molar conductivity measurements. The FT-IR spectra revealed that the dipeptide ligand is tetradentately coordinated to metal ions, with NNOO donor atoms participating in coordination with metal (II)/(III) ions, resulting in octahedral complexes. Using the recommended programme, the structural formula for the investigated ligand was optimized. Using the density-functional theory (DFT) approach, the energy gaps and other essential theoretical parameters were calculated. The agar diffusion method was used to test the in vitro biological characteristics of the ligand (H2L) and its transition metal complexes against Gram(+) bacteria (Bacillis subtilis and Staphylococcus aureus) and Gram(−) bacteria (Escherichia coli and Pseudomonas aeruginosa). The title compounds were found to be more biologically active than the parent dipeptide ligand. The title compounds have a good interaction with the crystal structures of 3t88-Escherichia coli, 3ty7-S. aureus, 5h67-Bacillus subtilis, and 5i39-Pseudomonasaeruginosa, according to molecular docking study. [ABSTRACT FROM AUTHOR]

Single crystals of hydrogen bonded 4-methoxyanilinium perchlorate (4MAPC) have been grown and the corresponding structure has been confirmed by Single crystal XRD analysis. The charge transfer on the nitrogen site of 4-methoxyaniline has been confirmed from elongated carbon and nitrogen bond distances. The Quantum chemical calculations of 4-methoxyanilinium perchlorate have been studied at HF and DFT methods with 6-311++G(d,p) level of theory to get the optimized geometry, FT-IR/FT-Raman spectra, charge distributions and the microscopic NLO efficiency of the title compound. The HOMO-LUMO analysis indicates that the electron delocalization and the energy gap between the HOMO-LUMO of the 4MAPC indicates the charge transfer within the molecule. The energy gap values between the molecular orbitals are 4.7358 eV (DFT)/6.8044(HF) eV, which makes the compound more reactive. The Population analysis has been studied and discussed. The Hirshfeld surface analysis suggests that the most significant contribution to the crystal packing is by O...H contacts (29%). The microscopic NLO parameters of 4MAPC have been calculated and the relative second order hyperpolarizability (γ) of the compound has found to be 47 times greater than that of standard Urea.. [ABSTRACT FROM AUTHOR]

Polya was the first to establish the concept of a counting polynomial in chemistry. Despite the fact that the spectra of the characteristic polynomial of graphs were exhaustively researched by quantitative means in order to ascertain the molecular orbitals of unsaturated hydrocarbons, the field garnered little attention from chemists for several decades. Polynomials can be used to produce a variety of significant topological indices, either explicitly or after calculating derivatives or numerical methods. Certain firmly related polynomials, namely Theta, Omega, PI, and Sadhana polynomials, subordinate the equidistant edges and non-equidistant edges of structural graphs, which have a rich application in computing the corresponding topological indices. A topological index is a numerical value associated with a network that predicts chemical, physical, and biological activities. This article investigates these polynomials for three classes of polycyclic aromatic hydrocarbons as hexa-peri-hexabenzocoronene, hexa-cata-hexabenzocoronene, and dodeca-benzo-circumcoronene. In addition, closed formulas for these polynomials' corresponding indices are proposed. [ABSTRACT FROM AUTHOR]

In this work, the structural conformation of pyrrole-2-carboxaldehyde was evaluated using potential energy surface (PES) scan employing DFT computations using B3LYP method with 6-311++G(d,p) level of basis set. The molecule assumed cis form in conformational ground state being more stable than the trans by 15.21 kJ mol−1 due to the orientation of the N–C–C = O dihedral angle. Existence of hydrogen bonds due to intra- and inter-molecular interactions was envisaged. The geometrical parameters of optimized monomeric and dimeric forms have been computed. The computational structural parameters of monomer are in good agreement with its experimental counterparts. The HOMO-LUMO energies were employed for determination of chemical reactivity descriptors. The electronic properties such as frontier molecular orbitals and Global reactivity descriptors were predicted using TD-DFT method. The local reactivity descriptors such as Fukui functions were investigated to determine the electrophilic and nucleophilic attacks within the molecule. The calculated first order hyperpolarizability value exhibited its suitability for non-linear optical applications. Furthermore, the electrophilic and nucleophilic regions of the molecule were studied by molecular electrostatic potential and Fukui functions. 1H and 13C NMR chemical shifts were evaluated using GIAO method employing the same level of theory. NPA analysis and thermodynamic parameters were also calculated. Determined the structure for monomer in cis form and dimer; and intra- and inter-molecular hydrogen bonding. NLO behavior was demonstrated from HOMO-LUMO band gap energy and first order hyperpolarizability. The reactivity sites for electrophilic, nucleophilic and radical attack were found from Fukui functions. MEP and NPA analysis were carried out. NMR chemical shifts, thermodynamic parameters and rotational constants were evaluated. [ABSTRACT FROM AUTHOR]

In this study, 6-chloro-1-isobutyl-3-methylpyrimidine-2,4(1H,3H)-dione was successfully synthesized and its structure was characterized via spectroscopic techniques, including 1H NMR, 13C NMR, FT-IR, and HRMS. Single crystals of this compound were grown in a suitable solvent system and optimized using single - crystal X-ray diffraction and density functional theory (DFT). The theoretical and experimental values were in good agreement, as indicated by the diffraction values. DFT was used to investing ate the physicochemical properties of the compounds by analyzing their frontier molecular orbitals and molecular electrostatic potentials. [ABSTRACT FROM AUTHOR]

The crystal structure of a 1,2,3-triazole fused heterocyclic derivative 2-(1-Benzyl-5-methyl-1H-1,2,3-triazol-4-yl)-4-(2,4-dichlorophenyl)-6-phenyl pyridine (DICLPY; 4h) is reported. The structural characterization is done by single crystal X-ray technique. The Hirshfeld surfaces (HS) and 2D fingerprint graphs are generated to investigate the inter atomic contacts contribution for structure by CrystalExplorer 17.5 program. The pairwise interaction energies between neighboring molecules are computed at the B3LYP/6-31G(d,p) method. This interaction energy analysis showed that the total stability of the DICLPY structure is mainly contributed by the dispersion force factor followed by the coulomb potential force factor. The DFT-based HOMO, LUMO orbitals and molecular electrostatic potential map are studied to identify the reactivity of our molecule. In-silico molecular docking technique is used to inspect the DICLPY compound as a possible antibacterial agent by docking with Glucosamine-6-phosphate synthase protein (PDB ID: 2VF5) using PyRx and AutoDock Vina programs. The molecular dynamics simulation is performed to examine the physical movement of our molecule DICLPY with Glucosamine-6-phosphate synthase protein for 100 ns time period. MD simulation revealed the greater stability of DICLPY and Glucosamine-6-phosphate synthase protein complex during the simulation period. [ABSTRACT FROM AUTHOR]

Vibrational spectra of 5-nitrobenzimidazole (5NBZ) have been tested and the density functional hypothesis are carried out to guarantee the vibrational assignments. The different vibrational modes of 5NBZ are actualized by utilizing the total energy distribution (TED). The molecular optimized limits and electronic properties of 5NBZ are explored by DFT/B3LYP strategy. The molecular orbital, Mulliken's plot, natural bond orbital (NBO) and molecular electrostatic potential (MEP) properties of 5NBZ have been studied. The theoretical UV-vis and NMR spectral analysis have been performed. The molecular docking process affirms that the 5NBZ acts as an inhibitor of EGFR and ERα proteins, which are important in breast cancer movement. Subsequently, this study clears the way for designing drugs for breast cancer action. In silico ADMET analysis has also been predicted for the molecule to evaluate its efficacy and drug-likeness. [ABSTRACT FROM AUTHOR]

The CM–L and CM+–L complexes for the three coinage metals, CM = Cu, Ag and Au interacting with three key ligands, L = CO, N2 and H2, are investigated. Calculations are undertaken using various quantum chemical methods to ascertain the equilibrium geometries and interaction energies; the latter are calculated at the coupled-cluster level of theory, and extrapolated to the basis set limit. Some of the neutral species are found to be particularly challenging, and significant disparity is found in some cases for the geometry and/or harmonic vibrational wavenumbers. In addition, molecular orbital diagrams, atomic charges, and orbital contour plots are presented, in order to gain insight into the interactions occurring in these complexes. [ABSTRACT FROM AUTHOR]

Benzenesulfonamide compounds containing piperazine heterocycles have prospective pharmacological activity. Two benzenesulfonamide compounds were synthesized. Based on density functional theory (DFT), the optimized structures of the two molecules were calculated using the B3LYP method. DFT was also used for further study of the molecular electrostatic potential and leading molecular orbital. Single crystal of 1-ethyl-4-(phenylsulfonyl)piperazine was studied. The intermolecular interaction and contact were quantified using Hirshfeld surface analysis and 2D fingerprint plots. Conformational analysis showed that the molecular structure after DFT optimization was consistent with the crystal structure determined by x-ray single crystal diffraction. [ABSTRACT FROM AUTHOR]

In this study, 1-(2-bromo-4-(dimethylamino)phenyl)-4-(2-chlorobenzyl)-[1,2,4] triazolo[4,3-a]quinazolin-5(4H)-one was synthesized via a five-step reaction and its single-crystal was obtained via solution crystallization, which was followed by crystallographic analysis. The molecular structure was calculated using density functional theory (DFT) and conformational analysis showed that the optimized molecular structure from DFT was comparable with that elucidated using X-ray diffraction. At the same time, the physicochemical properties of the compound could be understood by analyzing its frontier molecular orbitals and molecular electrostatic potentials. [ABSTRACT FROM AUTHOR]

The structural evolution, electronic property and spectral analysis of YGenq (n = 4–20, q = 0, −1) has been examined under the framework of density functional theory combined with the Artificial Bees Colony and the Saunders 'Kick' algorithm. The global minimum structure of the YGen- cluster is recognised by contrasting the simulated and measured photoelectron spectra (PES). Average binding energies, second difference energies, highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps are shown as size change and display abnormal stability at n = 16. Natural population analysis (NPA) shows the charge transfer from Ge to Y atom is 4.62 e in YGe16-, forming ionic bonds. HOMO–LUMO orbitals are mainly composed of Ge atoms. Electron localisation function (ELF) reveals the electrostatic force between Y and Ge atoms and the covalent interaction between each two Ge atoms, which is in accordance with the bond analysis. The current work shows that YGe16- is viewed as a promising building block for rare earth-doped semiconductor materials. [ABSTRACT FROM AUTHOR]

Edotecarin is an indolocarbazole class antitumor agent that has significant anticancer effects against various types of cancer, especially lung, breast, and stomach cancer.The conformation analysis of the edotecarin was performed using the PM3 method and six stable conformations were obtained.Afterwards the obtained lowest energy conformation was optimized at the DFT/B3LYP/6-31++G(d,p) level of theory. The vibrational wavenumbers, the highest occupied molecular orbital, the lowest unoccupied molecular orbital and molecular electrostatic potential of the most stable conformer of edotecarin were calculated at the DFT/B3LYP/6-31++G(d,p) level of theory.The molecular docking of the edotecarin molecule against DNA, Topoisomerase I, DNA-Topoisomerase I complex,α5β1 and αIIbβ3 integrins were performed to reveal its binding modes and binding affinities. [ABSTRACT FROM AUTHOR]

In this study, N-(1,1′-biphenyl)-2-chlorobenzoylthiourea (HL) and its metal complexes were prepared and their structural characterization was made using elemental analysis, FT-IR, 1HNMR, HR-MS, single crystal XRD techniques, and TG/DTA analysis. The crystal structure of HL was investigated using single crystal X-ray diffraction and was observed to crystallize in the monoclinic crystal system with P 1 21/c 1 space group, Z = 4, a = 7.3291(4) Å, b = 20.7880(10) Å, c = 12.0074(6) Å. The structures of the complexes and the molecular orbitals of HL were optimized at B97D/TZVP level. Investigation of the thermal and electrochemical behaviors of the Co(II), Ni(II), and Cu(II) complexes were found to be thermally stable up to 165, 185, and 122 °C, respectively. Cell viability test MTT was made to determine anticancer activities against MCF-7 breast cancer cells and 2,2-diphenyl-1-picrilhydrazyl and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid analysis for the antioxidant activity. The IC50 values against MCF-7 cells and was found to be in the range 24.3–49.2 µM. [ABSTRACT FROM AUTHOR]

The approximate CNDOL Fockian, together with the configuration interaction of single excitations ([CIS|CNDOL/21]), is applied to investigate the electronic properties of three different kinds of donors (D) considered suitable for photovoltaic devices, either as isolated systems or complexed with fullerene (C60) as potential acceptors (A). Calculated charge maps, together with the Coulomb-exchange term of CIS lowest transitions, are used to understand the electronic topology and possible behaviour of D-A excitons. The effects of varying donor structures are compared. The lowest excitation energies of the donor-C60 complexes arise from electron densities localised at the central ring units in the donors. Nevertheless, C60 does not always participate in electron sharing upon excitation. It sometimes acts only as a structural companion for enhancing or not the exciton capability to provide adequate photoelectric power conversion efficiencies. The [CIS|CNDOL/21] method is validated as a valuable tool for modelling structure-related properties of molecular excitons and for predicting the performance of D–A materials in relatively big supramolecular systems. It is shown that multi-electron CIS wavefunctions are at least as useful as one-electron molecular orbitals to describe charge-transfer properties of excitons and provide a physical picture of the whole electron density. [ABSTRACT FROM AUTHOR]

We have theoretically studied the hydrodesulphurisation (HDS) mechanism of thiophene and its hydrogenated derivatives over sulphided Co–Mo catalysts supported by four zeolites (ZSM-5, FAU, Beta, MCM-22) by a two-layer ONIOM (our Own N-layered Integrated molecular Orbital and molecular Mechanics) method. Due to low energy barriers, the thiophene can be hydrogenated to 2,3-dihydrothiophene (2,3-DHT), 2,5-dihydrothiophene (2,5-DHT) and tetrahydrothiophene (THT). Direct desulphurisation (DDS) and hydrogenolysis desulphurisation (HYD) pathways were investigated in detail. The calculated results show that in DDS mechanism of thiophene, the rate-determining step is the C–S bond cleavage. In HYD mechanisms of 2,5-DHT, 2,3-DHT and THT, the rate-determining step is hydrogen transfer on ZSM-5, FAU and Beta zeolites except MCM-22 zeolite. The HYD of 2,3-DHT and THT should occur by the stepwise pathway. But for the 2,5-DHT, the concerted pathway is probably more favourable than the stepwise pathway. The reduced density gradient (RDG), differential charge density (DCD), and local orbital locator (LOL) maps show that for all transition states (TSs), there are complicated van der Waals (VDW) and electrostatic interactions between the organic fragment and the catalytic centre. [ABSTRACT FROM AUTHOR]

In this study, the unbiased crystal structure analysis by particle swarm optimisation (CALYPSO) combined with the density functional theory (DFT) method were used to perform a structure search for neutral Cs2Bn (n = 1–12) clusters, as well as the corresponding global minimum of the potential energy surface were determined. The ground-state structures of the Cs2Bn (n = 1–12) clusters have four types of geometries: planar, arch bridge, double pyramid, and shield shape. Subsequently, the relative stability of the ground-state structures was systematically analysed based on three effective rules, which indicates that the C7V Cs2B8 with a double pyramid structure has unusual stability. The results of the molecular orbitals (MOs) and density of states analysis (DOS) show that the B-2s and 2p atomic orbitals of Cs2B8 are the main components of MOs. In addition, from the results of adaptive natural density partitioning (AdNDP) and localised orbital locator (LOL), it can be seen that the excellent stability of Cs2B8 originates from the delocalised large π bonds with aromaticity and the s–p bonding of B–B. Our results reveal the structural growth mode of Cs2Bn clusters and enrich the chemical bonding properties of boron-based clusters. [ABSTRACT FROM AUTHOR]

A series of cyclometalated platinum (II) complexes with aromatic ligands, such as pyridyl, pyrimidinyl, and pyrazolate, were investigated with theoretical calculations. To investigate the relationship between ligands with molecular orbital, molecular rigidity, electroluminescent properties, and spectroscopic properties, the electrostatic potential (ESP), density-of-states (DOS), and root mean squared displacement (RMSD) were calculated. On the basis of calculated absorption and phosphorescence data, the analysis of 'hole' and 'electron' have also been performed. From the RMSD and spin–orbit coupling (SOC) matrix elements calculations, complex 3 shows significant structural distortions on S1 state and it may be applied in thermal activation delayed fluorescence (TADF) materials. The electroluminescent properties calculations show that complex 1 is suitable for hole transport material and complex 4 can be applied to electron transport material. [ABSTRACT FROM AUTHOR]

In OLED devices 2,5-diphenyl-1,3,4-oxadiazole (PPD) is one of the most commonly used electron transport materials. Herein, equilibrium structures of PPD and its three fluorine-substituted derivatives, namely 2,5-bis(3-fluorophenyl)-1,3,4-oxadiazole (FPD), 2,5-bis(3,5-difluorophenyl)-1,3,4-oxadiazole (dFPD) and 2,5-bis(perfluorophenyl)-1,3,4-oxadiazole (pFPD) along with their corresponding molecular anions, have been optimized using DFT/B3LYP/6-31 + G(d,p) and DFT/ωB97XD/6-311 + G(d,p) techniques. The electro-optical parameters and global reactivity descriptors of all these molecules and molecular ions have been computed. Adiabatic electron affinity, vertical electron affinity and reorganization energy for estimating hole and electron transport have been obtained. Electronic transitions between molecular orbitals have been examined using UV-visible spectra. The addition of fluorine to PPD improves its electron affinity, which is advantageous for electron transport. The increased polarizability of fluorinated PPDs indicates that they are electronically more active than PPD molecules. Both the DFT methods reveal an almost similar pattern of electro-optical parameters, global reactivity descriptors and electron transport properties in fluorine-substituted PPD molecules. [ABSTRACT FROM AUTHOR]

Circularly polarised thermally activated delayed fluorescence (CP-TADF) molecules producing circularly polarised light which is beneficial to human eyes are widely used in circularly polarised organic light-emitting diodes. However, the relationship between the molecular structures and their luminescence properties of these CP-TADF molecules has not been well explained. Herein, the chiral molecule (R)-SFST with properties of circularly polarised luminescence (CPL) and thermally activated delayed fluorescence (TADF) is studied in detail. Firstly, we found two conformations by using molecular dynamic conformation search for (R)-SFST, namely (R)-SFST-a and (R)-SFST-b. The molecular geometric structures of singlet and triplet states are optimised by utilising density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods. Combining the thermal vibration correlation function methods, their photophysical properties are studied simultaneously. The processes of excited-state energy decay are revealed. The results show that the chiral units are more important to the molecular orbitals when the molecule has a more distorted configuration, which is beneficial to obtain CPL properties. However, when the molecular has rigid configuration, the excitons are easier to convert between S1 and T1, and the molecular has better TADF properties. Our results reveal the influence of different molecular conformations on CPL and TADF properties. [ABSTRACT FROM AUTHOR]

In the present study, we report the combined experimental and computational study along with antimicrobial screening of two tri-fluorinated chalcones from 1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)ethan-1-one. The (E)-1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-(4-(trifluoromethyl)phenyl)prop-2-en-1-one (DBTFP-1) and (E)-1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-(4-(trifluoromethoxy)phenyl)prop-2-en-1-one (DBTFP-2) were synthesized by the famous Claisen-Schmidt condensation reaction. The computational investigation of optimized molecular structures, bond lengths and bond angles were performed by using density functional theory (DFT) with a B3LYP functional and 6-31G(d,p) basis set. The electronic properties were computed using Time-Dependent density functional theory (TD-DFT) with a B3LYP functional and 6-31G(d,p) basis set for the optimized geometries. The lower band gap in DBTFP-1 demonstrated the inevitable intramolecular charge transfer. The UV-Visible simulations were performed in the gas phase and dichloromethane (DCM) solvent. The experimental UV-Visible analysis was performed in DCM solvent. The first singlet excited state was attributed to the n-π* and second singlet excited state to the π -π* electronic transition. The scaled vibrational bands of titled compounds were compared with experimental observations and correct vibrational assignments were made. Various global reactivity parameters were analyzed and discussed to apprehend the chemical behavior of the synthesized chalcones. MESP and contour surfaces revealed negative potentials near the oxygen atoms and positive potentials over the hydrogen atoms. Mulliken charge study revealed that C17 and C33 are the most negative and positive carbon atoms in DBTFP-1, respectively, whereas C17 and C35 are the most negative and positive carbon atoms in DBTFP-2. The antibacterial activity was performed against P. vulgaris and S. aureus and antifungal activity against A. niger and C. albicans. The antimicrobial activity for these two compounds was correlated with LUMO and band gap energy. The magnificent antimicrobial activity of DBTFP-1 was attributed to its more stabilized LUMO and lower band gap than DBTFP-2. [ABSTRACT FROM AUTHOR]

Fluorouracil or 5-fluoururacil (FU) has been used an important anti-cancer drug for for several types of cancers. Within this work, a model of C8B6N6 fullerene-like nanocage (CBN) for the drug delivery of FU. So, the quantum chemical density functional theory (DFT) calculations were performed to evaluate molecular and atomic features of the optimised models to affirm such a hypothesis for application in the drug delivery of FU. In this case, six bimolecular models of interacting CBN-FU complexes were detected based on the adsorption of FU by different positions at the surface of the CBN nanocage. The formation of the CBN-FU2 complex model was the strongest one. The structural analysis of FU could show that the urea-type oxygen atom (O2) had a significant role in the participation of FU in interactions with the CBN surface yielding the most favourable bimolecular model for the drug delivery of FU. The information provided by electronic molecular orbital descriptions and atomic quadrupole coupling constant (Cq) parameters affirmed the hypothesis of employing the proposed CBN fullerene-like nanocage for the drug delivery of FU anti-cancer. Accordingly, the quantum theory of atoms in molecules (QTAIM) indicated the physical interactions in the formation of CBN-FU complexes. [ABSTRACT FROM AUTHOR]

The structural and bonding properties of gas-phase M4C6 (M = Cu, Ag, and Au) clusters and their anions have been investigated by quantum chemical calculations. Theoretical results indicate that the lowest-energy isomers of Cu4C6−/0 clusters possess ring-like configurations. The binding motifs in the most stable isomers of Ag4C6−/0 and Au4C6−/0 clusters adopt similar linear cumulenic chain-shaped configurations. The chemical bonding analysis indicates that the M4C6−/0 (M = Cu, Ag, and Au) complexes have σ plus π double delocalized bonding characters and the C atoms exhibit strong covalent bonding interactions, especially for Ag4C6−/0 and Au4C6−/0 clusters. The molecular orbital analysis shows that M4C6 neutrals have shell-closed electronic structures with large HOMO−LUMO gaps, indicating that their high stability and chemical inertness. [ABSTRACT FROM AUTHOR]

Cocrystals are of immense applications in crystal engineering and pharmaceutical chemistry. Sulfathiazole is found to form cocrystals with theophylline (S1) and sulfanilamide (S2). The experimental and computed values assigned by potential energy distribution. Further natural bond orbital analysis, nonlinear optical properties, frontier molecular orbitals and molecular geometries were also calculated. Frontier orbital energies are used to predict the energy properties and model the possible charge transfer between the cocrystal constituents. The molecular electrostatic potential (MEP) surface reveals the various reactive surfaces in the cocrystal system, which is very important in deciding various biological activities. The ultraviolet-visible (UV-Vis) spectra show the possible electronic transitions of the molecules. Simulated electronic spectra using time dependent density functional theory (TDDFT) method with Coulomb-attenuating method, Becke 3-parameter, Lee-Yang-Parr (CAM-B3LYP) functional was used to investigate the suitability of the cocrystals to be used in dye-sensitized solar cell (DSSC). Moreover docking proves that S1 and S2 cocrystals act as potential inhibitors and paves the way for developing effective drugs. [ABSTRACT FROM AUTHOR]

The first principle calculations have been employed to study the structural, electronic and magnetic properties of gold contacted C 60 dimers that are substitutionally doped with boron and nitrogen atoms. Doping of C 60 dimers causes size changes, symmetry distortions, induced magnetism and the emergence of states above the Fermi level. Hybridisation of the molecular orbitals of the doped C 60 dimers with the states of the monoatomic gold chains leads to level broadening and significant changes in the spin-polarised densities of states. The variations in the obtained total magnetic moments indicate that the considered complexes are highly favourable for further investigations as building blocks of magnetic nano devices. Transmission spectrum of BN doped complexes shows a significant variation with different levels of doping. The I–V characteristics display rectifying behaviour for a controlled amount of doping enabling the dimers to act as molecular rectifiers. [ABSTRACT FROM AUTHOR]

1,3-Dipolar cycloaddition reaction of 3-hydroxy-1-(2-oxo-2-phenylethyl) pyridinium bromide (1) or 3-hydroxy-1-(3-nitrobenzyl) pyridinium chloride (2) with trimethylvinylsilane, methylsulfonyl chloride, and vinyl triphenylphosphonium bromide under the influence of sonoenergy leads to form six cycloadducts (3)–(8). The novel cycloadducts were characterized using Fourier transform infrared (FTIR) spectroscopy, mass spectroscopy (MS), and nuclear magnetic resonance (1H-NMR). In situ formation of polyaniline (PANI) composites in the presence of 0.1 g of each cycloadduct (CYC) led to form eight PANI/CYC composites (9)–(16). The newly synthesized composites were characterized by using transmission electron microscopy. All composites showed high electrical conductivity compared with PANI itself. The potential of new composites as anti-biofouling agents was evaluated. Compounds were observed to be the most potent antimicrobial/antifouling agents considering their toxicity against non-target sea organisms. [ABSTRACT FROM AUTHOR]

A new anthraquinone derivative, 1-(2,5-dimethylpiperazin-1-yl)anthracene-9,10-dione, was synthesized and characterized by Fourier Transform-Infrared, Raman and nuclear magnetic resonance analysis. The optimized molecular geometry was obtained using Density Functional Theory, B3LYP method with a 6-311++G(d,p) basis set. The fundamental vibrational wavenumbers, IR and Raman intensities were calculated for the optimized structure and simulated spectra were compared with the experimental vibrational spectra. The calculated highest occupied molecular orbital and lowest occupied molecular orbital energies indicated the presence of charge transfer within the molecule. The antibacterial activities of the new amino anthraquinone derivate against gram-positive and gram-negative bacteria were determined. Molecular docking simulations were performed with the new anthraquinone derivative and DNA to reveal its anticancer property. It was found that the anthraquinone derivate was bound to DNA with a high binding affinity (ΔG = −31.8 kJ/mol) and interacted with the DG10, DC11 and DG16 residues via the intermolecular hydrogen bonds. Moreover, to investigate the antiviral activity of the compound and to expose its action mechanism as an antiCOVID-19 agent, in silico molecular docking studies were performed on the Angiotensin-Converting Enzyme-2, and SARS-CoV-2 targets (holo and apo forms of main proteases Mpro and spike glycoprotein). [ABSTRACT FROM AUTHOR]

Iterative multireference configuration interaction (IMRCI) has been exploited to calculate the properties of small molecules. Atomisation energies of CH2(1A1), H2O, HF, CH(X2Π), OH(X2Π) and CH2(3B1), and singlet–triplet separations of CH2, NH2+, SiH2, and PH2+ are computed with MRCI and IMRCI. The accuracy of IMRCI is comparable to that of coupled-cluster singles, doubles, and perturbative triples (CCSD(T)), and better than that of MRCI. Singlet–triplet separations calculated with IMRCI are compared with the results of the second and third order Møller-Plesset perturbation theories, CCSD, CCSD(T), MRCI and FCI as well as experimental results. It is shown that the IMRCI method is both accurate and reliable. Moreover, the effect of the frozenness of the highest unoccupied molecular orbital (HUMO) on the IMRCI results is also investigated. It is demonstrated that the frozen HUMO approximation significantly lowers the computational cost of IMRCI with almost the same computational accuracy. [ABSTRACT FROM AUTHOR]

The metacarboxyphenyl ammonium dihydrogenomonophosphate (C7H4NH3OOH) H2PO4 was synthesized and studied by a combination of single-crystal X-ray diffraction analysis, infrared, Raman vibrational spectroscopy, and density functional computation (DFT) calculation. This compound crystallizes in the monoclinic system, with the central space group P21/c. Its unit-cell dimensions are a = 12.9361 (7) (Å), b = 11.7735 (6) (Å), c = 6.5764 (4) (Å), β = 102.668° (2), and V = 977.22 (9) Å3.The structure determined gives a clear description of the hydrogen bonds connecting the hydrogen phosphate H2PO4– with the organic matrix. The atomic arrangement of this compound is built up by symmetric (H4P2O8)2– dimers anions formed by two (H2PO4)– via hydrogen bonding O1—H...O3. Each (H2PO4)– aggregates with cation through hydrogen bond interactions of O–H...O(P) and N–H...O(P) types. The bands observed in the infrared and Raman spectra of (C7H4NH3OOH) H2PO4 are assigned based on the results obtained in the literature and based on the computational group analyses performed in the factor group C2h. Besides, the optimal molecular geometry, harmonic vibration frequencies, infrared intensities, and Raman scattering activities were calculated using the DFT approach performed with the Gaussian 09 program using the hybrid function B3LYP combining the three Becke parameters and the Lee-Yang-Parr exchange-correlation function using the 6-311 + G(d,p) base set. The highest occupied molecular orbital–lowest unoccupied molecular orbital properties and geometries of this compound were determined and discussed. The results of the calculated structural parameters are generally in agreement with the experimental investigations. The computational infrared and Raman spectra of the reference compound have been constructed. [ABSTRACT FROM AUTHOR]

In the present work, Grimme's D3 dispersion corrected density functional theory (DFT-D3) is used for the comparative study of cyclic polyaniline oligomers with linear and bent structures, for the first time. Molecular design and spectral characterisation of these compounds are performed at the B3LYP-D3/6-311G(d,p) and the B3LYP-D3/6-311++G(d,p) levels of theory. The formation mechanism of cyclic polyaniline oligomers compared to the linear and bent structures is discussed. Molecular orbital (MO) calculations are applied to study the electronic structure, and estimate the energy gap between the highest occupied (HOMO) and the lowest unoccupied (LUMO) molecular orbitals. The density of states (DOS) diagrams are used to evaluate the nature of valence and conduction bands and investigate the electrical conductivity. The calculated infrared (IR), ultraviolet-visible (UV-Vis) and nitrogen-15 nuclear magnetic resonance (15N NMR) spectra of these compounds are compared to the theoretical and experimental spectra of polyaniline. Results show that cyclic polyanilines are nonpolar in comparison to the linear and bent structures. The band gap of these molecules is larger than the linear and bent ones. The band gap of cyclic oligomers increases with the increasing size of the rings. These results provide useful information for the characterisation of these novel compounds. [ABSTRACT FROM AUTHOR]

We have theoretically investigated the hydrodesulphurisation (HDS) mechanism of hydrogenated thiophene over Cu–Mo-modified FAU zeolite using a two-layer ONIOM (our Own N-layered Integrated molecular Orbital and molecular Mechanics) study. The thiophene is hydrogenated to 2,3-dihydrothiophene (2,3-DHT), 2,5-dihydrothiophene (2,5-DHT) and tetrahydrothiophene (THT) due to moderate free energy barriers. Hydrogenolysis desulphurisation (HYD) and concerted direct desulphurisation (DDS) are discussed. Ring-opening, hydrogen transfer and C−S bond cleavage steps of thiophene derivatives are involved in the HYD process. The rate-determining steps are the hydrogen transfer step for 2,5-DHT and C−S bond cracking step for 2,3-DHT and THT. The concerted DDS pathway is probably more favourable than the HYD pathway in the desulphurisation of 2,5-DHT. The difference charge density (DCD) analysis reveals that for the ring-opening process, the electrons are migrated from the organic chain to the Cu–Mo catalytic centre. The reduced density gradient (RDG) plots indicate that both steric hindrance and a weak van der Waals (VDW) interaction exist between organic fragment and catalytic centre for all transition states (TSs). The localised orbital locator (LOL) maps suggest that there are strong covalent interactions and weak VDW interactions between the atoms in the forming chemical bonds. [ABSTRACT FROM AUTHOR]

In the present work a comparison of the electronic structures of the Linear carbon chains (LCC) with Boron linear chains (BnH2 and BnH4) and boron–nitrogen linear chains (Bn/2Nn/2H2 and Bn/2Nn/2H4) is made using ω B97X-D/6-311++G** level of theory. BnH2 and BnH4 show comparatively more delocalised molecular orbitals and lower electron densities than CnH2 and CnH4. CnH2 and CnH4 show much more efficient charge delocalisation than the other chains. For the first time it is reported that BnH4 chains also show helical molecular orbitals for n = 2,6,10. Modification of the helical orbitals of the cumulene chains was observed upon the introduction of boron atoms. [ABSTRACT FROM AUTHOR]

In this study, two new donor-acceptor type thermally activated delayed fluorescence materials using carbazole as a donor and cyano substituted benzene as an acceptor were synthesized. Structural parameters, molecular orbital densities, photophysical characteristics were determined. By changing the substitution position of the cyano groups on the phenyl rings, the relationship between structure and properties was also be disclosed. These materials were tested as emissive species for the fabrication of organic light-emitting diodes. The blue devices showed EL emission peaks at 464 and 488 nm with the CIE coordinates of (0.17, 0.18) and (0.21, 0.31), respectively. [ABSTRACT FROM AUTHOR]