Frontier Molecular Orbital Energy Gap Research Articles

Synthesis, Characterization, Band gap calculation, DFT study and Biological implication of Two Nitrogen-rich Proligands: Polymorphic Crystal Structures and Hirshfeld surface analyses of a Thiocarbohydrazone

A novel dihydrazone proligand 1,3-bis(pyridin-4-ylmethylideneamino)guanidine hydrochloride (H3L1) is reported along with polymorphic crystal structures of an analogous proligand 1,5-bis(4-pyridinecarboxaldehyde) thiocarbohydrazone (H2L2. H2O & H2L2. 2H2O). The crystal systems of H2L2. H2O and H2L2. 2H2O are monoclinic with P21/c and C2/c space groups. Strong hydrogen bonding interactions are found to be predominate in the H2L2. 2H2O crystal lattice. Hirshfeld surface analysis reveals that, after isotropic H···H interactions, N···H and C···H interactions are found to have the highest contribution to the overall Hirshfeld surface areas of H2L2. H2O and H2L2. 2H2O respectively. The pore volume and surface area of the thiocarbohydrazone polymorphs are also calculated. Direct band gap energies for H3L1 and H2L2 in their solid-states were estimated as 2.33 and 2.58 eV respectively using the Kubelka-Munk model. Molecular geometry of both the compounds are optimised using density functional theory and quantum chemical parameters are calculated. Frontier molecular orbital energy gaps in the gas phase for H3L1 and H2L2 are found to be 4.49 and 3.55 eV respectively, which indicates strong intermolecular interaction in the solid lattice of H3L1. Absorption, distribution, metabolism and excretion (ADME) attributes indicate both compound's potential as drug candidates. In vitro antibacterial study reveals that the thiocarbohydrazone based proligand is a more efficient inhibitor against gram-positive Staphylococcus aureus bacterial species. The anticancer activities of the compounds against MCF-7 human breast cancer cells suggested that H3L1 with an IC50 value of 172.6798 µg/mL has more potent than H2L2 (IC50 value of 279.1881 µg/mL).

Structural, spectral analysis, reactivity, topological and pharmacological investigations on an antihistamine agent

In this work, quantum computational techniques have been applied to the title compound (Methyl [2-(pyridin-3-yl) ethyl] amine) for insights into structural, vibrational, and electronic spectral features and chemical reactivity. The observed vibrational spectra in solid-phase have been compared with the theoretical one (DFT together with B3LYP /6–311++G (d, p). For the understanding of intra-molecular hyper conjugative interactions, a natural bond orbital (NBO) study was carried out. Nonlinear optical (polarizabilities) calculations have been performed. The molecule's bioactivity is confirmed by the frontier molecular orbital energy gap, and information regarding intra- and inter-non-covalent interactions is provided by non-covalent bond interaction (NCI) analysis. Molecular electrostatic potential (MEP) can identify a molecule's electrophilic and nucleophilic areas, and it can explain a molecule's chemical implications using electron localization function (ELF). The compound's reactive sites were examined using the Fukui function computations, and the molecule's reactivity is defined by its chemical descriptors. The bioactivity of a molecule is supported by molecular docking using the Histamine 1 receptors 3RZE and 7DFL protein, and drug likeness factors were computed to understand the biological properties of MP3EA.

Synthesis, vibrational analysis, absorption and emission spectral studies, topology and molecular docking studies on sulfadiazine derivative

AbstractA new class of (N‐(pyrimidin‐2‐yl)‐4‐((1,7,7‐trimethylbicyclo [2.2.1] heptan‐2‐ylidene) amino) benzenesulfonamide (CDA) was synthesized from commercially available camphor and sulfadiazine. The synthesized Schiff‐base was characterized by FT‐IR, 1H and 13C NMR spectroscopic analyses. The HOMO, LUMO, MEP, chemical reactivity parameters, and NBO were calculated using the WB97XD/cc‐pVDZ basis set. For better understanding, the electronic absorption and emission of the compound were recorded using UV‐Vis and fluorescence spectra. Molecular docking simulations were investigated between ligand (compound) and target protein. The computational results correlate well with observed values. The frontier molecular orbital energy gap (3.78 eV) revealed that the studied molecule has higher polarizability and chemical reactivity with lower kinetic stability. In addition, compound showed the highest binding score −5.72 kcal/mol, which was confirmed by a molecular docking simulation.

Design and Exploration by Quantum Chemical Analysis of Photosensitizers Having [D-π-π-A]- and [D-D-triad-A]-Type Molecular Structure Models for DSSC.

Density functional theory (DFT) calculations are performed on the newly developed and designed photosensitizers having [D-D-triad-A]- and [D-π-π-A]-type structural models for near-infrared absorption dye-sensitized solar cells (DSSCs). For this purpose, three novel molecules are designed, which are named as follows: [naphthalene-anthracene-thiophene-furan-benzonitrile] as dye S1, [coronene-anthracene-thiophene-furan-benzonitrile] as dye S2, and [fluorene-thiophene-furan-benzonitrile] as dye S3. In all three systems, benzonitrile is the acceptor moiety, while thiophene and furan are bridging moieties. Naphthalene and anthracene are donor moieties in S1, whereas coronene and anthracene are donor moieties in S2, and fluorene is the only single donor moiety used for designing the dye complex S3. All three dye complexes are optimized under the DFT framework by using the B3LYP hybrid functional with 6-31G(d,p) basis set on Gaussian 16W software. The absorption spectra are calculated utilizing time-dependent density functional theory (TD-DFT) with the CAM-B3LYP/6-31G(d,p) basis set. The calculated absorption maxima of S1 and S2 are 749.45 and 750.04 nm, respectively, while for S3, it is reported to be at 337.35 nm, which suggests that the designed molecular structure having a double-donor moiety is suitable for high absorption wavelength. Further, the analysis of frontier molecular orbital energy gap suggests that the molecular systems S1, S2, and S3 have values 2.17, 2.13, and 3.618 eV, respectively, which lie in the semiconducting region. The other parameters calculated for the photovoltaic performance are exciton binding energy, change in free energy of charge regeneration, change in free energy of charge injection, oscillator strength, light harvesting efficiency, and open-circuit voltage.

Synthesis, characterization, molecular docking, and cytotoxicity study of ruthenium (II/III) polypyridyl complexes

A new polypyridyl ligand 4‐(4‐nitrophenoxy)‐N,N‐bis (pyridin‐2‐ylmethyl)aniline (L1) and its three ruthenium (II/III) complexes, [Ru (Cl)3L1] (C1), [Ru(L1)2]Cl (C2), and [RuCl (dpa)L1] (C3) where dpa = 2,2‐dipyridylamine, have been successfully synthesized and characterized using Fourier‐transform infrared spectroscopy (FTIR), elemental analysis, proton nuclear magnetic resonance (1H NMR), high‐resolution electrospray ionization mass spectrometry (HR‐ESI‐MS), thermal analysis (thermogravimetric analysis [TGA] and differential scanning calorimetry [DSC]), UV/Vis absorption, and magnetic susceptibility. The structures of the ligand and the complexes were optimized, and the structural characteristics were determined by density functional theory (DFT) using the B3LYP‐GD3/6‐311G++(d,p) method. Optimized FTIR vibrational frequencies and 1H NMR chemical shifts agreed well with the corresponding experimental FTIR and 1H NMR data. In vitro cytotoxicity of the ligand and the complexes were evaluated against the MCF‐7 breast cancer cell line. Ligand L1 was the most potent with an IC50 of 38.45 μM, followed by C2 with an IC50 of 45.23 μM. However, the ligand and the complexes showed low antiproliferative activity compared to cisplatin, which had an IC50 of 9.67 μM. To predict the reactivity trend of L1 and the complexes, frontier molecular orbital (FMO) analysis was performed. The FMO energy gap (Eg = ELUMO − EHOMO) for C2 was found to be 1.675 eV, which was the lowest among all the complexes or L1. In addition, molecular docking studies were carried out so as to predict the binding capacity of L1 and the complexes to estrogen receptor alpha (ER‐α). The results showed that C2 has the most negative binding energy score (−9.63 kcal/mol), which indicates more stable adducts with the key amino acid residues at the active sites of ER‐α. Furthermore, C2 displayed the lowest inhibition constant (Ki) of 0.09 μM compared to all the complexes or L1. These results are very promising and show that the novel complex C2 may help in the development of anticancer drugs.

Evaluation of Antioxidant Properties and Molecular Design of Lubricant Antioxidants Based on QSPR Model

Two quantitative structure–property relationship (QSPR) models of hindered phenolic antioxidants in lubricating oils were established to help guide the molecular structure design of antioxidants. Firstly, stepwise regression (SWR) was used to filter out essential molecular descriptors without autocorrelation, including electronic, topological, spatial, and structural descriptors, and multiple linear regression (MLR) was used to construct QSPR models based on the screened variables. The two models are statistically sound, with R2 values of 0.942 and 0.941, respectively. The models’ reliability was verified by the frontier molecular orbital energy gaps of the antioxidants. A hindered phenolic additive was designed based on the models. Its antioxidant property is calculated to be 20.9% and 11.0% higher than that of typical commercial antioxidants methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and 2,2′-methylenebis(6-tert-butyl-4-methylphenol), respectively. The structure–property relationship of hindered phenolic antioxidants in lubricating oil obtained by computer-assisted analysis can not only predict the antioxidant properties of existing hindered phenolic additives but also provide theoretical basis and data support for the design or modification of lubricating oil additives with higher antioxidant properties.

Facile and green synthesis, crystal structure, antibacterial activity, Hirshfeld surface analysis, and computational investigation of a novel lithium(I) complex: Comparisons of theoretical and experimental analyses

A novel monovalent lithium complex, [Li(C6H4NO3)(H2O)2] (1), was prepared via a simple one-pot green reaction of 2-hydroxypyridine-3-carboxylic acid (2-hpca) with lithium carbonate and aminoguanidine (Amgu) bicarbonate in water. Complex 1 was investigated using elemental, ultraviolet–visible, Fourier transform infrared (FT-IR), thermal, and single-crystal X-ray diffraction (SC-XRD) measurements. We found that 1 crystallized in the monoclinic C2/m space group with a = 12.800(2) Å, b = 6.6657(13) Å, and c = 9.4687(19) Å. The Li ion exhibited four coordinates with a distorted square planar geometry. That is, the ion was surrounded by four oxygen atoms, of which two were derived from two water molecules, one was from the carboxylate group, and one was from the keto group of the 2-oxo-1,2-dihydropyridine-3-carboxylate ligand. Simultaneous thermogravimetry–differential thermal analysis of 1 exhibited dehydration followed by continuous low-temperature (∼400 °C) decomposition to produce lithium oxide as the end product in an air atmosphere. Furthermore, density functional theory (DFT) analysis was conducted to compare the theoretical and experimental data collected via SC-XRD. In addition, DFT was used to analyze the frontier molecular orbital energy levels and energy gaps. Moreover, we conducted Hirshfeld surface studies with respect to 1 to differentiate between the intermolecular hydrogen bond contacts. Energy frameworks for 1 were produced by analyzing the energy interactions between intermolecular hydrogen bonds to investigate the prevailing interactions involved in molecular packing. The in silico results showed that 1 has high potential for the development of antimicrobial drugs. Molecular docking studies were also conducted to determine the binding energy of 1 with Staphylococcus aureus (5CZZ) and Escherichia coli (3T88). The results were consistent with the experimental data obtained from the antibacterial activity of 1 with respect to Staphylococcus aureus and Escherichia coli.

Clitoria ternatea flower extract: Biopolymer composite-based triboelectric nanogenerator as a self-powered smart counter

The development of biopolymers-based high-performance triboelectric nanogenerators (TENGs) for powering innovative electronics is crucial for green energy technologies. Herein, a novel TENG composed of polyvinyl alcohol (PVA) functionalized with electron-donating groups from Clitoria ternatea (CT) flower extract is proposed. The compatibility of composite film in energy harvesting devices is tested through various characterizations, including structural, surface, electrical, and bioassay. Interestingly, the enhanced tribopositivity of the composite is attributed to intermolecular hydrogen bonding between taraxerol and PVA, substantiated by Hartree-Fock-DFT calculated vibrational spectrum, frontier molecular orbital energy gap, and electrostatic potential maps. TENG with PVA-CT: Polyurethane generated an open-circuit voltage (VOC) of 14.8 times and short-circuit current (ISC) of 32.7 times, more significant than PVA TENG and several bio/non-biodegradable tribonegative polymers. The long-term stability test of PVA-CT TENG is confirmed by an observation of constant VOC for eight consecutive months. Additionally, humidity studies reveal that output increases with an increase in relative humidity of 30–100%. Further, the PVA-CT TENG is efficient in charging capacitors, powering LEDs, and acts as a self-powered smart counter. Overall, this study contributes new insights into developing eco-friendly synergistic materials for TENG fabrication and extending its applications in the Internet of Things, facilitating to build of futuristic smart cities.

Spectroscopic, Biological, and Topological Insights on Lemonol as a Potential Anticancer Agent.

A monoterpene alcohol known as lemonol was investigated experimentally as well as theoretically in order to gain insights into its geometrical structure, vibrational frequencies, solvent effects on electronic properties, molecular electrostatic potential, Mulliken atomic charge distribution, natural bond orbital, and Nonlinear Optical properties. The frontier molecular orbital energy gap values of 5.9084 eV (gas), 5.9261 eV (ethanol), 5.9185 eV (chloroform), 5.9253 eV (acetone), and 5.9176 eV (diethyl ether) were predicted, and it shows the kinetic stability and chemical reactivity of lemonol. Topological studies were conducted using Multiwfn software to understand the binding sites and weak interactions in lemonol. The antiproliferative effect of lemonol against the breast cancer cell line Michigan Cancer Foundation (MCF-7) was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, while nuclear damage, condensation, and reactive oxygen species generation were identified using acridine orange/ethidium bromide, propidium iodide, and dichlorodihydrofluorescein diacetate staining. The theoretical and experimental findings are highly correlated, confirming the structure, and the results of in vitro studies suggest that lemonol acts as a potent inhibitor against the human breast cancer cell line MCF-7, highlighting its strong antiproliferative activity.

Synthesis, functional group analysis (experimental and theoretical), solvent –Solute interactions, structural insights of (E)-3-(4-chloro-3-(trifluoromethyl) phenyl) imino) indolin-2-one–In-vitro Antimicrobial activity

(E)-3-(4-chloro-3-(trifluoromethyl) phenyl) imino) indolin-2-one (4CTFI) has been synthesised and its structural features have been investigated by spectroscopic (FT-IR, FT-Raman, NMR and UV–vis) techniques. 4CTFI was optimized in gas phase, PA (polar aprotic), PP (polar protic) and NP (nonpolar) solvent phases using WB97XD/6-311++G(d,p) method. Vibrational assignments pertaining to different modes of vibration with potential energy distribution (PED) have been augmented by normal coordinate analysis (NCA). Using natural bond orbital (NBO) analysis, the compound's electronic stability as a consequence of hyper conjugative couplings and charge delocalization has been assessed. The Fukui functions and Molecular Electrostatic Potential (MEP) surface have been utilized to provide information about the nucleophilic and electrophilic locations for the aforesaid phases. The frontier molecular orbital (FMO) energy gap probably indicates a compound's strong chemical reactivity and enables eventual charge transfer inside the molecule. Furthermore, electron-hole distributions for four excited states and topological studies have been discussed. Moreover, this chemical adheres to Lipinski's decree, which implies that, in concept, consuming an oral intake will not be troublesome. ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) attributes have been investigated to evaluate drug discovery initiatives of our synthetic molecule. Docking of 4CTFI with antimicrobial proteins have been performed and the minimum binding energy of -6.52 kcal/mol was obtained for 4WAS protein. Macromolecule flexibility and stability on protein-ligand interactions have been effectively studied using the molecular dynamics simulation. Tests of in-vitro antimicrobial efficacy have been performed on microbial strains.

Structural and vibrational characterizations, DFT calculations, second harmonic generation, molecular docking studies on L–argininium 3,3-dimethylacrylate

This study is aimed to understand the structure, stability, and properties of L-argininium 3,3-dimethylacrylate (ADMA) crystals. These single crystals were cultivated through a solution growth method. The structure describes the orthorhombic crystal system with four molecules per unit cell, and crystallizes in a non-centrosymmetric (P212121) space group. A systematic structural analysis of ADMA was carried out using density functional theory (DFT) with a B3LYP/6-31+G* basis set to examine the intra/intermolecular type of bonding interactions, excitation energies, vibrations, and electrostatic interaction between the charged particles. The protonated L-argininium cation and dissociated 3,3-dimethylacrylate anion are joined via N–H⋯O hydrogen bonds with R22(8) to form an asymmetric unit of ADMA. The energy of interaction between l-arginine and 3,3-dimethylacrylic acid molecules was calculated to be 17.95 kcal mol−1 (75.09 kJ mol−1), leading to the formation of a 1:1 salt molecule. Additionally, the Density Functional Theory (DFT) calculations supported the assignment of vibrational bands. The calculated frontier molecular orbital energy gap 4.702 eV indicating the charge transport that happens between the cation and the anion. Furthermore, global chemical reactivity descriptors were calculated. The degree of second harmonic generation response of the orthorhombic phase of ADMA was found to be 0.22 relative to potassium dihydrogen phosphate. In addition, first-order hyperpolarization susceptibility calculations confirm the nonlinear optical activity of the ADMA crystal. The present study also focuses on the anti-breast cancer activity of ADMA using three breast cancer proteins (Protein Data Bank codes: 5NWH, 5NQR, and 1OQA) by molecular docking studies.

Hyperconjugation and Hydrogen Bonding Interactions Effect with the Nonlinear Optical Features of 4-Chlorophenoxy Acetonitrile: An Experimental and DFT Methodology

The compound 4-cholorophenoxy acetonitrile (CPAN) was examined using Nonlinear optical properties in the current study. With the aid of normal coordinate analysis and the SQMFF methodology, vibrational analysis of FT-IR and FT-Raman has been conducted. Natural bond orbital analysis is used to analyze the electronic stability of the compound created by hyper conjugative contacts and charge delocalization, and the Frontier molecular orbital energy gap confirms the molecule’s optical activity. ESP recognizes the nucleophilic and electrophilic areas of molecules, and the chemical implication of molecules was explained using ELF, LOL. Third-order nonlinear optical (NLO) investigations are carried out on a CPAN crystal using the Z-scan technique, and optical properties are established.

Graphene Embedded with Transition Metals for Capturing Carbon Dioxide: Gas Detection Study Using QM Methods

Carbon dioxide (CO2) adsorption on decorated graphene (GR) sheets with transition metals (TMs) including iron, nickel and zinc was investigated for removing this hazardous gas from the environment. TM-doped GR results in higher activity toward gas detecting than pristine graphene nanosheets. TM embedding restrains hydrogen evolution on the C sites, leaving more available sites for a CO2 decrease. The Langmuir adsorption model with ONIOM using CAM-B3LYP functional and LANL2DZ and 6-31+G (d,p) basis sets due to Gaussian 16 revision C.01 program on the complexes of CO2→(Fe, Ni, Zn) embedded on the GR was accomplished. The changes of charge density illustrated a more considerable charge transfer for Zn-embedded GR. The thermodynamic results from IR spectroscopy indicated that ΔGads,CO2→Zn@C−GRo has the notable gap of Gibbs free energy adsorption with a dipole moment which defines the alterations between the Gibbs free energy of the initial compounds (ΔGCO2 o and ΔGZn@C−GRo) and product compound (ΔGCO2→Zn@C−GRo) through polarizability. Frontier molecular orbital and band energy gaps accompanying some chemical reactivity parameters represented the behavior of molecular electrical transport of the (Fe, Ni, Zn) embedding of GR for the adsorption of CO2 gas molecules. Our results have provided a favorable understanding of the interaction between TM-embedded graphene nanosheets and CO2.

Advancing insights towards electrocatalytic activity of La/Ba-Sr-Co-Fe-O-based perovskites for oxygen reduction & evolution process in reversible solid oxide cell

Electrocatalytic activity of La/Ba-Sr-Co-Fe-O-based mixed ionic and electronically conducting (MIEC) perovskites has been studied for selective oxygen reduction (ORR) and evolution (OER) processes applicable in Reversible Solid Oxide Cell (R-SOC). XPS study establishes scavenging of oxygen vacancy in LSCF and generation of the same in BSCF. BSCF enables faster oxygen ion transport and is correlated with lower frontier molecular orbital (FMO) energy gap of 1.18 eV derived from density functional theory (DFT). Relatively higher ΔEFMO(Absolute) 1.75 eV in LSCF accounts for higher charge transfer. Amperometric measurements @800℃ in asymmetric cell configuration exhibit lowest time-dependent current loss of 0.019 mA.h-1 & 0.035 mA.h-1 for BSCF & LSCF under applied anodic (+0.8 V) and cathodic potentials (-0.8 V) for 200 h with respective surface resistances (Rs) of 0.19 Ω.cm2 and 0.081 Ω.cm2. H2 flux of 0.4Nl.h-1.cm-2 obtained with BSCF, establishes its effectivity as OER whereas LSCF is found to be more selective in ORR.

Synthesis, spectroscopic studies, and single‐crystal structures of two 3‐D supramolecular zinc(II) and nickel(II) complexes containing thiazole ring: Antimicrobial assays, time‐dependent density functional theory calculations, and Hirshfeld surface analysis

Two novel complexes [Zn(L)2·(NO3)2] (1) and [Ni(L)2·2H2O]·2CH3OH·(NO3)2 (2) (L = 2‐(2‐thiazolyl)‐4‐methyl‐1,2‐dihydroquinazoline‐N3‐oxide) were synthesized successfully and characterized by elemental analysis, as well as various spectroscopic techniques. Specifically, the photoluminescence behavior of complex 1 was explored in different solvents. The structural characterization of both complexes has been determined single‐crystal X‐ray diffraction. It revealed that the metals in 1 and 2 are chelated by two L ligands in centro‐symmetrically fashion and the complexes are counterbalanced by nitrate ions which act as coordinating species in 1, while two water molecules complete the Ni coordination sphere in 2. In the crystal structures, the adjacent molecules of complex 1 disclosed a ladder‐like 2‐D network and 3‐D supramolecular self‐assembly. Simultaneously, an infinite 1‐D chain, 2‐D layered skeleton, and even meter‐shaped 3‐D network of 2 was governed by molecular interactions (H–bonds, C–H⋯π). Most strikingly, the research of antibacterial activity proved that two complexes had good activity against two standard bacteria strains. To ascertain deeply the optimum geometric configurations and detect the frontier molecular orbital energy gaps, density functional theory (DFT) calculations were also investigated. Additionally, analyses of Hirshfeld surfaces (HS) and electrostatic potential (ESP) were also performed to quantify the presence of diverse noncovalent interactions.

Synthesis of 3-Methoxy-6- [(2, 4, 6-trimethyl-phenylamino)-methyl]-phenol Schiff base characterized by spectral, in-silco and in-vitro studies

The structure of the title compound (I) (C17H19NO2)2 the Schiff base, {3-Methoxy-6-[(2,4,6-trimethyl-phenylamino)-methyl]-phenol} was characterized by 1H, 13C NMR, UV–VIS and IR spectroscopic techniques. The crystal structure was determined by X-ray analysis. The compound (I) was crystallized in the Monoclinic space group P21/c, with a = 25.9845 (12), b = 7.3318 (4), c = 16.3543 (8) Å, β = 100.713(°) (4), and Z = 8. The intermolecular interactions of the compound (I) was analyzed using Hirshfeld surface and Fingerprint analysis. Based on the crystal-void calculation, the volume of the void and surface area of the Schiff base compound (I) was described. The frontier molecular orbital energy gap reveals charge transfer interactions involving donors and acceptors. The invitro studies on antibacterial property of the title compound shows best MIC value for Staphylococcus aureus and the compound effect on MTT assay on A549 lung cancer cell line. The molecular docking result shows that the compound has good molecular-level interaction with anticancer drug target having good interactions with active site residues. The non-covalent interactions in the protein-ligand complex were well established from NCI analysis.

The chemical adsorption effect of surface enhanced Raman spectroscopy of nitrobenzene and aniline using the density functional theory

Nitrobenzene and Aniline are representatives of the nitro or amino compounds of benzene, mainly used in the manufacture of dyes, spices, medicines, and so on. Extensive use of Nitrobenzene and Aniline may cause pesticide residue pollution and have carcinogenic effects on organisms. In this paper, the Nitrobenzene and Aniline single molecules and their complexes with gold nanoparticles are studied theoretically by Raman spectroscopy, the surface-enhanced Raman spectroscopy (SERS) and the density functional theory (DFT) simulations. Selective binding of gold nanoparticles (AuNPs) to the analyte was used to study the molecular electrostatic potential (MEP), frontier molecular orbital (FMO) and the Raman activity spectra of Nitrobenzene and Aniline, as well as the Raman activity spectrum of the complexes. The most electronegative sites of Nitrobenzene and Aniline are found in the MEP and the hypothesis that these sites might be the adsorption sites of Nitrobenzene/Aniline molecules at the gold surface. At the same time, the MEP of the Nitrobenzene/Aniline complexes also prove the existence of the charge transfer effect between Nitrobenzene/Aniline and Au. The FMO energy gap of Nitrobenzene/Aniline is 0.18983 eV and 0.18953 eV, respectively, and which, after adding the Au3 clusters, change to 0.03376 eV and 0.0797 eV, respectively, indicating that the Nitrobenzene/Aniline-Au3 complexes have stronger chemical activities and are more prone to the charge transfer effects. The electrophilic indices of Nitrobenzene (0.17921 eV) and Aniline (0.05635 eV) are calculated and analyzed, as well as that of Nitrobenzene/Aniline-Au3 complexes after adding the Au3 atomic clusters, 0.80819 eV and 0.19819 eV, respectively. The obvious increasing trend in the electrophilic indices of the Nitrobenzene/Aniline-Au3 complexes indicate their stronger biological activities and more prone to chemical reactions. The chemisorption of Nitrobenzene/Aniline and gold nanoparticles complexes is studied by the SERS, and the Raman formation of the complexes at different binding sites of Nitrobenzene/Aniline and Nitrobenzene/Aniline-Au3 is well explained by the surface selection rule. The reason for the selective enhancement of the spectral peaks presented in the Raman activity spectrum is calculated, and the enhancement factor of the chemical enhancement due to the charge transfer effect is calculated as well. The reason for the peak offset in the SERS spectrum to the conventional Raman spectrum is explained.

Investigations on spectroscopic, ADMET properties and drug-likeness, molecular docking, chemical properties of (2E)-3-(biphenyl-4-yl)-1-(2,4-dichlorophenyl)-prop-2-en-1-one by combined density-functional theory

The title compound, (2E)-3-(Biphenyl-4-yl)-1-(2,4-dichlorophenyl)-prop-2-en-1-one (BPDC) has been derived from the compounds namely biphenyl-4-carbaldehyde and 2,4-dichloroacetophenone to perform 3D-Potential energy conformations for molecular stability by DFT calculation of B3LYP/6-311++G(d,p). The geometrical optimization and atoms vibrational spectral data observed FT-IR and FT-Raman spectra values were compared with theoretical values (B3LYP, CAM-B3LYP). The molecule was characterized by absorbed infrared radiation, scattered Raman techniques with the attention on important functional groups (Cl, O, N). Electro negativity difference has been discussed and their biochemical and biomedical properties have been examined. The chemical reactivity of the compound was characterized by MEP-map, NHO, NLMO, and NBO analyses. The frontier molecular orbital (HOMO–LUMO) energy gap, vertical electron truncation of UV–Visible spectrum, and their λ-max value have been compared with CAM-B3LYP and M062X/6-311++G(d,p) approach data. The orbitals arrangements were studied by the density of states (DOS) and the partial density of states (PDOS). BPDC is investigated by Hirshfeld surface analysis that employs three-dimensional contours and two-dimension fingerprint area for intermolecular interactions quantitatively. The biological investigations like drug-likeness and toxicity properties of BPDC molecule were conformed to Lipinski's rule of five and ADMET properties, respectively. The title molecule exhibits a good bioactive score and less toxicity. Antibacterial and also antifungal activities of BPDC were done by docking analysis.

Binding and Photocleavage Studies of Ru (II) Polypyridyl Complexes with DNA: An In Silico and Antibacterial activity

The global crisis of bacterial infections, search for an effective antibacterial is of utmost clinical significance. Experimental and computational approaches used to study the DNA binding of [Ru(A)2L] (ClO4)2.2H2O, where A=ancillary ligand; phen=1, 10 Phenanthroline (1), dmp=4,4’-dimethyl-1,10 -orthophenanthroline (2), bpy = bipyridyl (3) & dmb=4, 4’-dimethyl 2, 2’- bipyridine (4), Lis a novel intercalator ligand MPPIP=(2-(1-(2-methoxyphenyl)-1H-pyrazol-4-yl)-1H-imidazo [4,5-f][1,10]Phenanthroline) and their antibacterial activity. The synthesized complexes and their DNA affinity studies were executed by absorption, emission, and viscosity techniques to show binding via intercalation. The intrinsic binding constant, Kb indicates that the simple ancillary ligands (phen and bpy) are more robust binding. The 3D Conformational analysis shows slight distortion from octahedron geometry. The molecular descriptors calculated from the frontier molecular orbital energy gap, ΔE point that the complex of phen show higher binding with DNA. Further analysis of the molecular attributes show that the pyrazole ring of the intercalator Ligand is significant for DNA binding. Furthermore, the molecular docking studies of the Ru (II)-MPPIP complexes with DNA exhibit an inclination towards Guanine-rich sites by the Nitrogen of the pyrazole ring. Biological investigations establish that all the complexes were active against S. aureus and E. coli.

A combined experimental and theoretical study of alkyl 2-(3-benzoyl-4‑hydroxy-1,1-dioxido-2H-benzo[e][1,2]thiazin-2-yl)acetates: Synthesis, X-ray crystallography and DFT

Benzothiazine derivatives belongs to an important class of organic compounds with a wide range of application in the field of biotechnology and medicinal chemistry, and many of its derivatives have been considered in drug discovery. A series of three alkyl 2-(3-benzoyl-4‑hydroxy-1,1-dioxido-2H-benzo[e][1,2]thiazin-2-yl)acetates (3a–c) were synthesized from the sulfonimidamides through multistep reactions. The molecular geometry of these compounds has been investigated with the help of X-ray crystallography and quantum mechanical calculations. The molecular structural optimization and structural properties were calculated using the Density Functional Theory method and B3LYP hybrid functional with 6–311+G* basis set. Non-covalent interactions studies, energetics and reactivity properties of 3a-c compounds have been explored through local and global reactivity descriptors, UV-Visible spectral analysis and molecular electrostatic potential illustrations. It is found that the compound 3b is more reactive than others because of its lowest frontier molecular orbital energy gap (ΔE=3.46 eV) and low chemical hardness (η=0.23eV) than others. Furthermore, the investigations of Non-linear optical properties and thermodynamic parameters have also been carried out which shows that these compounds can be used as a non-linear optical material in the field of telecommunication and information technologies.