Unoccupied Molecular Orbitals Research Articles

Hyperbranched polyimide with triazole core structure for nonvolatile resistive switching memory

AbstractHyperbranched polyimides (HBPIs) possess a unique branched structure, which can make the lowest unoccupied molecular orbitals (LUMOs) degenerate and reduce the bandgap between the highest occupied molecular orbital (HOMO) and LUMO energy levels. The triazole group can facilitate the charge transfer process. Thus, a novel hyperbranched polyimide (HBPI‐TZA‐6FDA) has been prepared from new triazole derivative triamine monomer (TZA) and 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) for memory device. The memory device with the structure ITO/HBPI‐TZA‐6FDA/Al exhibits a low‐threshold voltage of −2.2 V and a high ON/OFF current ratio of about 105. Meanwhile, the memory device shows nonvolatile write once read many times (WORM) type memory behavior and excellent stability with an operation time of 104 at a continuous applied voltage of −1 V. Optical, electrochemical experiments, and molecular simulation have been carried out to illustrate the memory performance. The memory performance is governed by the charge transfer between TZA and 6FDA units. The branched structure and triazole unit can reduce the band gap between HOMO and LUMO energy levels effectively, which is favorable for improving charge transfer and reducing threshold voltage. The HBPI‐TZA‐6FDA‐based memory device is favorable for memory device applications due to its relatively low‐power consumption and high‐operation stability.

Application of biphenylene nanosheets for metronidazole detection

The goal of this study is to explore whether biphenylene nanosheet (BPNS) and its doped counterparts (B- and Al-BPNS) can be used as sensors for metronidazole (MN) using the density functional theory. The study used the B3LYP functional along with the 6–31 + G(d) and 6–31++G(d,p) basis sets and considered both gas and implicit solvent phases. The most stable configuration of pristine and doped BPNS:MN complexes was identified by optimizing the geometry of all probable conformations obtained from the molecular electrostatic potential plots of nanosheets and the drug molecule. The adsorption of MN on the surface of pristine BPNS resulted in an adsorption energy (Eads) of −18.3 and −16.9 kcal.mol−1 (first and second digits indicate the data obtained from the 6–31 + G(d) and 6–31++G(d,p) basis sets, respectively). The electrical properties of pristine BPNS, identified by the highest occupied and the lowest unoccupied molecular orbitals (HOMO and LUMO, respectively), remained unchanged upon adsorption of MN. The predicted time for desorption of the MN drug from the BPNS surface is about 2.5 × 10−3 and 2.3 × 10−4 s. The study suggests that pristine BPNS is not a suitable carrier and biosensor for MN drug molecules. Therefore, the doping technique was explored to enhance the sensing features of BPNS towards the MN molecule. The results showed that the Eads value of B-BPNS is about −20.6 and −20.1 kcal.mol−1, which is higher than that of pristine BPNS. However, the electrical properties of B-BPNS are not sensitive to the presence of MN molecules. The predicted time for desorption of the MN drug from the surface of B-BPNS is about 1.2 × 10−1 and 5.2 × 10−2 s. Adsorption of MN on the surface of Al-BPNS causes an adsorption energy of −25.0 and –23.6 kcal.mol−1. However, the HOMO-LUMO energy gap decreased by approximately 26.3 % and 24.5 %, upon Al doping, which is favorable from a sensing point of view. The predicted time for desorption of the MN drug from the Al-BPNS is about 2.0 × 102 and 1.9 × 101 s. These findings suggest that Al-BPNS could be used as a suitable carrier and biosensor for MN drug molecules.

Density functional theory calculations, vibrational spectral analysis and topological analysis of 1-acethyl-2(4-isopropoxy-3-methoxyphenyl) cyclopropane with docking studies

A systematic spectroscopic investigationof 1-acethyl-2(4-isopropoxy-3-methoxyphenyl) cyclopropanewasperformed by utilizing Density functional theory approaches at B3LYP level usingGaussian 09 W software package. The FT-IR and FT-Raman techniques were utilized to assign the spectral properties of the title compound. On the basis of Natural Bond Orbital (NBO) analysis,the transfer of second order perturbation energies and ElectronDensity (ED) from filled lone pairs of Lewis base to unfilled Lewis acid sites wereanalysed. The chemical stability,distribution of energy and energetic behaviour of the compound were calculated from the Highest Occupied and Lowest Unoccupied Molecular Orbital (HOMO-LUMO) Analysis. The nucleophilic and electrophilic locales of the moleculewas perceived by the Molecular electrostatic potential (MEP). NCI investigation gives data around the inter and intra non covalent interlinkages. By using the Multiwavefunction software the topological analysis of ELF and LOL were performed. The chemical reactivity sites were determined by means of the fukui function. The assignments of vibrational spectra were computed using thevibration energy distribution analysis (VEDA). Drug similarityfactors were intended to understand the biological aspects. Vadar software was used to generate the Ramachandran plot. The bioactivity of the title compound was confirmed fromthe molecular docking studies.

Molecular-Simulation-Inspired Synthesis of [6]-Prismane via Photoisomerisation of Octafluoro[2.2]paracyclophane.

Prismanes have been attracting interest for nearly 50 years because of their geometric symmetry, highly strained structures, and unique applications due to their high carbon densities and bulky structures. Although [3]-, [4]-, and [5]-prismanes have been synthesised, [6]-prismanes and their derivatives remain elusive. Herein, fluorine chemistry, molecular mechanics, molecular orbital package, and density functional theory calculations were used to design and implement the photoisomerisation of octafluoro[2.2]paracyclophane (selected based on the good overlap of its lowest unoccupied molecular orbitals and short distance between the benzene rings) into octafluoro-[6]-prismane. Specifically, a dilute solution of the above precursor in CH3CN/H2O/dimethyl sulfoxide (DMSO) (2:1:8, v/v/v) solution was irradiated with ultraviolet light, with the formation of the desired product confirmed through the use of nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. The product was thermally stable in solution but not under work-up conditions, which complicated the further analysis and single-crystal preparation. The key criteria for successful photoisomerisation were the presence of fluorine substituents in the cyclophane structure and DMSO in the solvent system. A more stable derivative design requires the isolation of prismane products. The proposed fluorination-based synthetic strategy is applicable to developing novel high-strain molecules/materials with three-dimensional skeletons.

Calculation of Charge Transport Phenomena and Mobility Analysis in the Insulating Oil Using First Principle and Marcus Theory.

Oil-paper insulation is widely used as a reliable composite insulation system in power transformers. The dielectric property of oil insulation plays an important role in the reliable operation of power equipment. To recognize the charge transfer process in composite insulation, the mobility of the charge in aged insulating oil is studied. However, few studies have been conducted on the microscopic mechanism of charge transport phenomena at the molecular level. In this research, we have studied the molecular electronic structure and the distribution of holes and electrons in the insulating oil by first-principles calculation. By combining with Marcus theory, the corresponding electron coupling energy, reorganization energy, and free energy are obtained. The corresponding charge hopping model is chosen by the parameter relation, and the hopping rate is calculated. At last, the mobility of holes and electrons in insulating oil within the insulation is simulated by the Monte Carlo method. Other possible charge migration methods are also studied and discussed for the comparison. It is observed that the transfer integral of electrons is 2 orders of magnitude larger than that of holes, which is mostly due to the localization of lowest unoccupied molecular orbitals (LUMO). The hole and charge transfers accord with Marcus hopping, the adiabatic charge transfer model, and the charge hopping rate is obtained. The actual free energy action under an external electric field is obtained by calculating polarizability and permittivity. Monte Carlo simulation is used to obtain the charge transfer image and mobility under an actual electric field. Possible types of traps and mobility of ions and clusters in the insulating oil are also studied.

Charge balance in OLEDs: Optimization of hole injection layer using novel p‐dopants

AbstractCharge balance is one of the most important factors for realizing high performance organic light emitting devices (OLEDs). In this work, we provide a novel strategy to improve the charge balance in OLEDs by optimizing the hole injection layer (HIL) as well as the electron transporting layer (ETL) and thereby controlling the charge carrier supplies in the device. First, we develop a p‐dopant material (PD02), with a lowest unoccupied molecular orbit (LUMO) of −4.63 eV, much shallower than that of the commercial material (PD01) of which the LUMO is −5.04 eV. Nevertheless, this enables us to modulate the supply of holes to the emissive layer through tuning doping concentration. We demonstrate that device performances are significantly improved by employing such a scheme. With a 23% molar doping of PD02, a bottom emission red OLED achieves an external quantum efficiency (EQE) of over 30%, an operating voltage of 3.4 V and a LT95 ~15,000 h at 10 mA/cm2, with a Digital Cinema Initiative P3 (DCI‐P3) chromaticity of CIE (X, Y) = (0.68, 0.32). Moreover, the efficiency roll‐off is suppressed up till ~3500 cd/m2, a desirable feature in display applications. The lateral conductivity of by using such HIL is also found to be much lower than that of PD01, resulting in reduced crosstalk among RGB pixels. Next, a new electron transporting material (ETM‐02) with a deep LUMO of −2.86 eV is also introduced to further optimize the charge balance. Although devices with ETM‐02 shows lower voltage and higher EQE, lifetime is compromised. In order to improve lifetime, additional fine tuning of the charge balance is essential. Finally, a second p‐dopant PD03 with a LUMO of −4.91 eV is added to the HIL to further extend the modulation flexibility in the hole injection. A double‐layer HIL consisting of 8 nm of HTM:16% PD02 and 2 nm of HTM:3% PD03, where the former is in contact with anode, is adopted in the device structure. The bottom emission deep red device achieve EQE over 30%, an operating voltage of 3.2 V and an improved LT95 ~13,000 h at 10 mA/cm2 with a BT.2020 range chromaticity of CIE (X, Y) = (0.701, 0.299). In the double HIL configuration, the introduction of PD03 provides one more parameter for tuning and therefore improves the overall device performances.

Synthesis, characterization and theoretical aspects of copper and zinc divalent ion complexes with azo dye derived from 4,5-diphenylimidazole

Azo dye ligand derived from 4,5-diphenyl imidazole and 4,4-diaminodiphenylmethane was synthesized by diazomium coupling reaction. In this reaction an amine (4,4-diaminodiphenylmethane was converted to the diazonium salt and coupled with 4,5-diphenyl imidazole. The bright coloured Cu(II) and Zn(II) complexes with this ligand were synthesized by refluxing the latest with both metals chloride salts. The prepared compounds were characterized by 1H-NMR, 13C-NMR, FTIR, UV-Visible, molar conductivity and atomic absorption. By the infrared data, the coordination between copper and zinc ions and the azo ligand achieved through the nitrogen of the azo group and one of the nitrogen atoms in the imidazole ring. By the molar conductivity test, the non- electrolytic nature of both complexes was also confirmed. The suggested structure for these complexes is octahedral. Using density functional theory (DFT) some theoretical data was obtained for the synthesized complexes. The obtained data include the highest occupied and the lowest unoccupied molecular orbitals energy (HOMO and LUMO), electron density, thermodynamic functions (ΔG°, ΔS°, ΔH°, ΔE°), ionization potential (IP), electron affinity (EA), electrophilicity(ὠ), electronegativity (En), chemical hardness (η) and dipole moment (μ). According to these studied parameters some properties of the two complexes were explained and discussed.
 KEY WORDS: Cu(II) and Zn(II) complexes, Azo ligand, 4,5-Diphenylimidazole, 4,4-Diaminodiphenylmethane, Theoretical study
 Bull. Chem. Soc. Ethiop. 2024, 38(2), 313-323. 
 DOI: https://dx.doi.org/10.4314/bcse.v38i2.4

Plasmon induced hot carrier distribution in Ag20 -CO composite.

The interaction between plasmons and the molecules leads to the transfer of plasmon-induced hot carriers, presenting innovative opportunities for controlling chemical reactions on sub-femtosecond timescales. Through real-time time-dependent density functional theory simulations, we have investigated the enhancement of the electric field due to plasmon excitation and the subsequent generation and transfer of plasmon-induced hot carriers in a linear atomic chain of Ag20 and an Ag20 -CO composite system. By applying a Gaussian laser pulse tuned to align with the plasmon frequency, we observe a plasmon-induced transfer of hot electrons from the occupied states of Ag to the unoccupied molecular orbitals of CO. Remarkably, there is a pronounced accumulation of hot electrons and hot holes on the C and O atoms. This phenomenon arises from the electron migration from the inter-nuclear regions of the C-O bond towards the individual C and O atoms. The insights garnered from our study hold the potential to drive advancements in the development of more efficient systems for catalytic processes empowered by plasmonic interactions.

Spin Coupling Effect on Geometry-Dependent X-Ray Absorption of Diradicals.

We theoretically investigate the influence of diradical electron spin coupling on the time-resolved X-ray absorption spectra of the photochemical ring opening of furanone. We predict geometry-dependent carbon K-edge signals involving transitions from core orbitals to both singly and unoccupied molecular orbitals. The most obvious features of the ring opening come from the carbon atom directly involved in the bond breaking through its transition to both the newly formed singly occupied and the available lowest unoccupied molecular orbitals (SOMO and LUMO, respectively). In addition to this primary feature, the singlet spin coupling of four unpaired electrons that arises in the core-to-LUMO states creates additional geometry dependence in some spectral features with both oscillator strengths and relative excitation energies varying observably as a function of the ring opening. We attribute this behavior to a spin-occupancy-induced selection rule, which occurs when singlet spin coupling is enforced in the diradical state. Notably, one of these geometry-sensitive core-to-LUMO transitions excites core electrons from a backbone carbon not involved in the bond breaking, providing a novel nonlocal X-ray probe of chemical dynamics arising from electron spin coupling.

Synthesis and Characterization of New Hybrid Organic-Inorganic Metal Halides [(CH3)3SO]M2I3 (M = Cu and Ag).

Recently, all-inorganic copper(I) metal halides have emerged as promising optical materials due to their high light emission efficiencies. This work details the crystal structure of the two hybrid organic-inorganic metal halides [(CH3)3SO]M2I3 (M = Cu and Ag) and their alloyed derivatives [(CH3)3SO]Cu2-xAgxI3 (x = 0.2; 1.25), which were obtained by incorporating trimethylsulfoxonium organic cation (CH3)3SO+ in place of Cs+ in the yellow-emitting all-inorganic CsCu2I3. These compounds are isostructural and centrosymmetric with the space group Pnma, featuring one-dimensional edge-sharing [M2I3]- anionic double chains separated by rows of (CH3)3SO+ cations. Based on density functional theory calculations, the highest occupied molecular orbitals (HOMOs) of [(CH3)3SO]M2I3 (M = Cu and Ag) are dominated by the Cu or Ag d and I p orbitals, while the lowest unoccupied molecular orbitals (LUMOs) are Cu or Ag s and I p orbitals. [(CH3)3SO]Cu2I3 single crystals exhibit a semiconductor resistivity of 9.94 × 109 Ω·cm. Furthermore, a prototype [(CH3)3SO]Cu2I3 single-crystal-based X-ray detector with a detection sensitivity of 200.54 uCGy-1 cm-2 (at electrical field E = 41.67 V/mm) was fabricated, indicating the potential use of [(CH3)3SO]Cu2I3 for radiation detection applications.

Spectroscopic Studies on Structurally Modified Anthraquinone Azo Hydrazone Tautomer: Theoretical and Experimental Approach.

A series of unique four mono-azo substituted anthraquinone analogue were synthesized by using the anthraquinone components in the diazo-coupling technique. The FT-IR, 1H NMR, and HRMS, data were used to confirm the structure of the molecules, and spectroscopic techniques like UV-Vis, and photoluminescence spectroscopy were employed to estimate the photophysical properties of the molecules. The molecular optimized geometry and frontier molecular orbitals were estimated using density functional theory. Further, global chemical reactivity descriptors parameter was theoretically estimated using the value of the highest occupied molecular orbit and lowest unoccupied molecular orbits. The anti-tubercular action of the synthesised dyes were also examined. The results of this biological activity showed that N-isopropyl aniline combined with anthraquinone N-isopropyl aniline had superior anti-tubercular activity when compared to Rifampicin as the standard. As per molecular docking studies, the synthesized compound Q1 showed excellent binding energy (-10.0kcal/mol) among all compounds against the 3ZXR Protein. These results agreed with our in-vitro anti-TB activity results.

Spectroscopic (FT-IR, FT-Raman, NMR and UV–vis), quantum calculation, molecular structure, solvent interaction, ADME and molecular docking investigation on 4-oxo-4h-1-benzopyran-2-carboxylic acid

The present work, spectroscopic and quantum computational study has been carried out for the molecule 4-oxo-4H-1-benzopyran-2-carboxylic acid. The stable conformer of the title molecule was identified using Potential Energy Surface (PES) scan. The structural and geometrical parameters of the stable conformer of the molecule were determined by Density Functional Theory (DFT) using B3LYP method along with the basis set 6-311++G(d,p) through Gaussian 09 W software. The theoretical and experimental investigations such as Vibrational (FT-IR and FT-Raman), UV–visible and NMR analysis were done. The FT-IR were recorded in the region of (4000–400 cm−1) and FT-Raman in the region of (4000–100 cm−1), and the vibrational bands were compared with the theoretical values. Carbon NMR and Proton NMR spectra have been analyzed in DMSO solution. The theoretical chemical shift values were determined using Gauge Independent Atomic Orbital (GIAO) method. The intermolecular and intra-molecular bonding of orbitals and transfer of charge were studied using the Natural Bond Orbital (NBO) analysis. The respective transitional study was done through UV–vis's spectra and theoretical values predicted using TD-DFT (Time Dependent – DFT) method for both gas and solvent (ethanol) state. HOMO (Highest Occupied Molecular Orbital) – LUMO (Lowest Unoccupied Molecular Orbital) energy gap results prove the exchange of charges inside the molecule. Molecular Electrostatic Potential (MEP) is used to identify the nucleophilic and electrophilic sites of the molecule. To check the bioactive nature of the title molecule the drug-likeness was determined. Molecular docking is used to analyze the biological activity of the title molecule. The distribution of torsional angles in a protein structure is viewed by the Ramachandran plots of the molecules.

Unveiling structural and energetic characterization of the emissive RNA alphabet anchored in the methylthieno[3,4-d]pyrimidine heterocycle core.

This study presents a comprehensive theoretical exploration of the fluorescent non-natural emissive nucleobases- mthA, mthG, mthC, and mthU derived from the methylthieno[3,4-d]pyrimidine heterocycle. Our calculations, aligning with experimental findings, reveal that these non-natural bases exert minimal influence on the geometry of classical Watson-Crick base pairs within an RNA duplex, maintaining H-bonding akin to natural bases. In terms of energy, the impact of the modified bases, but for mthG, is also found to be little significant. We delved into an in-depth analysis of the photophysical properties of these non-natural bases. This investigation unveiled a correlation between their absorption/emission peaks and the substantial impact of the modification on the energy levels of the highest unoccupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbital (LUMO). Notably, this alteration in energy levels resulted in a significant reduction of the HOMO-LUMO gap, from approximately 5.4-5.5 eV in the natural bases, to roughly 3.9-4.7 eV in the modified bases. This shift led to a consequential change in absorption and emission spectra towards longer wavelengths, elucidating their bathochromic shift.

Corrosion Inhibition of Mild Steel in HCl Solution Using MPO: Experimental and Theoretical Insights

Corrosion is a pervasive challenge in various industrial applications, particularly in acidic environments. This comprehensive study delves into the effectiveness of 2-methyl-4-propyl-1,3-oxathiane (MPO) as a corrosion inhibitor for mild steel exposed to hydrochloric acid (HCl) solutions. The investigation employs weight loss techniques to assess the inhibitor's performance over varying durations (ranging from 1 to 48 hours) and concentrations (0.1 to 1 mM). At a concentration of 0.5 mM, the inhibitor demonstrates impressive inhibitory efficiency, ranging from 87.6% at 303 K to 92.9% at 333 K during a 5-hour exposure period. Additionally, the impact of temperature on the corrosion inhibition process is examined at temperatures of 303, 313, 323, and 333 K, showing substantial inhibition efficiencies. Quantum chemical calculations using Density Functional Theory (DFT) methods elucidate the molecular interactions between MPO and the metal surface. Notably, the analysis of EHOMO (Highest Occupied Molecular Orbital Energy), ELUMO (Lowest Unoccupied Molecular Orbital Energy), Egap (Energy Gap), total hardness (η), electronegativity (χ), and electron fraction transition atom (ΔN) reveals valuable insights into MPO's corrosion inhibition capabilities. The outcomes underscore MPO's potential as an effective corrosion inhibitor for mild steel in HCl environments, laying the groundwork for more efficient corrosion prevention strategies in industrial settings.

Computational Investigation of Corrosion Inhibition Properties of Hydrazine and Its Derived Molecules for Mild Steel

Corrosion of mild steel has gained a lot of attention by many industries and academia. This study was aimed to find the corrosion inhibition properties of hydrazine and its 11 derived molecules for mild steel using computational method, namely, the density functional theory with Beck 3‐parameter Lee Yang and Parr functional along with the 6‐311++G (d, p) basis set using simple quantum chemical parameters. The main quantum chemical parameters were energies of highest occupied and lowest unoccupied molecular orbitals and their energy gap, dipole moment, hardness, softness, electrophilicity index, the fractions of electrons transmitted, the change energy back‐donation, electron‐donating power, electron‐accepting power, molecular electrostatic potential, and Fukui function as well as polarizability. The results indicated that hydrazine derivatives have good anticorrosion nature which is consistent with the experimental findings. Out of the 12 target inhibitor molecules, N′‐(3‐nitrobenzylidene) hydrazine carbodithioic acid (NBHCA) and N′‐(4‐dimethylaminobenzylidene) hydrazine carbodithioic acid (DABHCA) are the most effective inhibitors. According to the value of the quantum chemical parameters, EHOMO, ΔEgap, Χ, η, σ, ε, ΔN, α, and ΔEb-d DABHCA showed the top effective anticorrosion inhibitor, and by the value of the quantum chemical parameters, ELUMO, TE, ω−, and ω+ NBHCA showed an effective anticorrosion inhibitor. The quantum chemical parameter data showed that NBHCA and DABHCA are nearly equivalent in their values, which is consistent with experimental values. Furthermore, a multiple‐linear regression equation was proposed as a quantitative structural activity relationship model to relate the calculated molecular descriptors of hydrazine derivatives to their experimental inhibition efficiencies obtained from literature. As a result, this model showed an excellent accuracy with an R‐squared of 0.924 and this uses to predict inhibition efficiencies of another molecules.

Tenability on schiff base Hydrazone derivatives and Frontier molecular orbital

Context hydrazine compounds based on 1,3,5-triazine were synthesised and their molecular structures were characterised by elemental analysis, Electronic, IR and 1H NMR spectra. The spectral behaviour of the newly prepared compounds in organic solvents of different polarities was extensively studied and correlated to the molecular structure. In this study, 1,3,5-Triazine derivatives (L1, L6, L7, L8) have been subjected to theoretical studies using the Semi-empirical PM3 quantum chemical method. The physical-chemical properties of some Hydrazone derivatives are determined theoretically. The molecular geometry, the Highest Occupied Molecular Orbital (HOMO) - Lowest Unoccupied Molecular Orbital (LUMO) energy gap, molecular hardness (η), ionisation energy (IE), Electron affinity and total energy were analysed, and applications as biological effects were done.

Study of A Ferroelectric Liquid Crystal Mesogen by Geometrical Optimization and Electro-Optic Characterization

In the present work one biphenyl benzoate cored liquid crystal was characterized using geometrical optimization and electro-optic study. Geometry of the molecule was optimized using Hartree-Fock method with 3-21G basis. The simulated value of molecular length and dipole moment was reported. The Infrared (IR) spectra were also simulated and analyzed. The energy gap between highest occupied molecular orbit (HOMO) and lowest unoccupied molecular orbit (LUMO) was calculated. The phase transition temperatures and phase sequences were identified by observing the topological defects in the optical textures at different temperatures under polarizing microscope. It exhibited ferroelectric smectics C* (SmC*) phase for a wide range of temperature and then directly melted into isotropic phase. The optical tilt angle of the compound was measured in SmC* phase and was fitted with mean field model to explore the nature of phase transition. The applicability of the compound for display applications were judged based on the parameters measured.

Comparative Computational Study on Molecular Structure, Electronic and Vibrational Analysis of Vinyl Bromide based on HF and DFT Approach

In this study, we have used the Hartree-Fock and Density Functional Theory method of calculation and compared the equilibrium configuration, electronic and vibrational mode of Vinyl Bromide molecule. The molecule is geometrically optimized initially by using 6-31G basis set with B3LYP functional and then bond angles, bond lengths, dihedral angles and IR spectra are compared respectively. Various groups of atoms in Vinyl Bromide molecule by DFT has more accurate bond length, bond angle values rather than by HF computation when comparing with the experimental values. The ground state energies are found at angle 10° or 180° or 360° using HF and DFT method of calculation for the H4-C1-C2-Br6 position. Values of the carbon-hydrogen, carbon-carbon and carbon-bromine bond lengths and bond angles for optimization state of C2H3Br molecule using Hartree-Fock and Density Functional Theory methods with respect to the basis set 6-31G have been analyzed. The C−H in-plane bending vibration and C−H out-of-plane bending vibrations occur in the region 1400–1050 cm-1 and 1000–675 cm-1 respectively. The electronic properties, such as Highest Occupied Molecular Orbital and Lowest Unoccupied Molecular Orbital energies are performed by HF and DFT approach and the difference in Highest Occupied Molecular Orbital and Lowest Unoccupied Molecular Orbital energy gap for HF and DFT method are 14.0847 eV and 6.8994 eV respectively

Synthesis and biological evaluation of novel benzenesulfonamide incorporated thiazole-triazole hybrids as antimicrobial and antioxidant agents.

A library of 20 novel benzenesulfonamide incorporating thiazole tethered 1,2,3-triazoles 1-4a-e was synthesized and screened for their antimicrobial, antioxidant,and cytotoxicity studies. Amoxicillin and fluconazole were used as reference antibacterial and antifungal drugs, respectively. Further, energies of frontier molecular orbitals were calculated for all the synthesized target compounds 1-4a-e to correlate electronic parameters with the observed biological results. Global reactivity descriptors, includinghighest occupied molecular orbitals-lowest unoccupied molecular orbitals energy gap, electronegativity, chemical hardness, chemical softness, and electrophilicity index, were also calculated for the synthesized molecules. All the tested compounds possessed moderate to excellent antibacterial potency; however, 3d and 4d exhibited the overall highest antibacterial effect (minimum inhibitory concentration [MIC] values 5-11 µM) while 2c showed the highest antifungal effect (MIC value 6 µM). Compound 3c exhibited the highest antioxidantactivity with a % radical scavenging activity value of 95.12. The cytotoxicity of the compounds 1-4a-e was also checked against an animal cell line and a plant seed germination cell line, and the compounds were found to be safe against both the tested cell lines.

Hexadecanoic acid analogs as potential CviR-mediated quorum sensing inhibitors in Chromobacterium violaceum: an in silico study

Chromobacterium violaceum is a Gram-negative, rod-shaped and opportunistic human pathogen. C. violaceum is resistant to various antibiotics due to the production of quorum sensing (QS)-controlled virulence factor and biofilm formation. Hence, we need to find alternative strategies to overcome the antimicrobial resistance and biofilm formation in Gram-negative bacteria. QS is a mechanism in which bacteria’s ability to regulate the virulence factors and biofilm formations leads to disease progression. Previously, hexadecanoic acid was identified as a CviR-mediated quorum-sensing inhibitor. In this study, we aimed to discover potential analogs of hexadecanoic acid as a CviR-mediated quorum-sensing inhibitor against C. violaceum by using ADME/T prediction, density functional theory, molecular docking, molecular dynamics and free energy binding calculations. ADME/T properties predicted for analogs were acceptable for human oral absorption and feasibility. The highest occupied molecular orbitals and lowest unoccupied molecular orbitals gap energies predicted and found oleic acid with –0.3748 energies. Docosatrienoic acid exhibited the highest binding affinity −8.15 Kcal/mol and strong and stable interactions with the amino acid residues on the active site of the CviR protein. These compounds on MD simulations for 100 ns show strong hydrogen-bonding interactions with the protein and remain stable inside the active site. Our results suggest hexadecanoic acid analogs could serve as anti-QS and anti-biofilm molecules for treating C. violaceum infections. However, further validation and investigation of these inhibitors against CviR are needed to claim their candidacy for clinical trials. Communicated by Ramaswamy H. Sarma