B3LYP Level Research Articles

Comparative assessment of structure–property relationships of new Cu(II) complex in selected density functionals

In order to evaluate the structure–property relationships of Cu(II) complex by using DFT methods, the structure of the newly synthesized Cu(II) complex, [Cu(6-Brpic)2(bpy)], was investigated by XRD, FTIR, UV–Vis, and fluorescence spectroscopic methods. In addition, Hirshfeld surface and NBO analyses were fulfilled to identify possible interactions in the intermolecular and coordination environment. The five different DFT methods (HCTH, M06L, TPSSTPSS, B3LYP, and CAM-B3LYP levels), having four different functionalities (the GGA, meta-GGA, hybrid-GGA, and range-separated hybrid), were carried out so as to investigate the structure–property relationship, considering the geometric parameters (bond lengths and angles), vibrational frequencies, electronic absorption wavelengths, electronic transitions, and linear and nonlinear optical parameters. The R2 for structural and vibrational parameters, as well as MPD%, MAD, an optimal scaling factor (λ) and overall root mean square (RMS) deviation, were considered only at vibration frequencies. While it was determined that M06-L and TPSSTPSS levels gave the best results for the bond lengths and angles of the Cu(II) complex, the best results for vibrational frequencies were obtained in the HCTH method along with these methods. In NLO parameters, the static and dynamic first-order hyperpolarizability (<β(0;0,0)> and β(−ω;ω,0)/<β(−2ω;ω,ω)>) values, the largest values were obtained in the HCTH method (38.817 × 10−30 and 437.86 × 10−30/201.55 × 10−30 esu), whereas the smallest values were found to be in the CAM–B3LYP/TPSSTPSS levels (6.118 × 10−30 esu, 8.270 × 10−30/11.730 × 10−30 esu). By regarding the static γ (<γ(0;0,0,0)>) and dynamic (<γ(−ω;ω,0,0)> parameters, the largest values were calculated in the M06L (232.101 × 10−36) and HCTH (1711.52 × 10−36) methods and the smallest values were obtained in the CAM–B3LYP (43.281 × 10−36 and 60.844 × 10−36) method. In fact, it is obviously seen that the β and γ values obtained by the aforementioned DFT levels are many times higher than that of the standard molecule of urea. These results indicate that the Cu(II) complex may be used as a potential NLO material to evolve optoelectronic devices.

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

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

Corrosion inhibition efficiency of quinoxalines based on electronic structure and quantum computational analysis

Based on the quantum chemical parameters obtained from density functional theory (DFT) with 6-311++ G (d, p) basis set at B3LYP level, a theoretical study of the corrosion inhibition effectiveness of 1-[4-acetyl-2-(4-chlorophenyl) quinoxalin-1(4H)-yl] acetone (A), 2-(4-(2-ethoxy-2-oxoethyl)-2-p-tolylquinoxalin-1(4H)-yl) acetate (B) and 2-(4-methylphenyl)-1,4-dihydroquinoxaline (C) were evaluated. A number of quantum chemical parameters were determined to assess the array of molecules selected, including lowest unoccupied molecular orbital energy, highest occupied molecular orbital energy, hardness, ionization potential, the electronegativity, dipole moment, the fraction of electrons transferred to the metal surface, total energy and softness. Experiments were found to be in agreement with theoretical data.

Prediction of control temperature and emergency temperature of monadic/binary aromatic nitro compounds by quantitative structure-property relationship: correlation study of self-accelerating decomposition temperature in thermal hazard assessment.

The thermal hazard of reactions caused by the structural instability of aromatic nitro compounds is a major concern in the field of chemical process safety and one of the main causes of major thermal runaway (TR) accidents such as fire and explosion. Among them, the self-accelerating decomposition temperature (SADT), as an important parameter, has been widely used to evaluate the thermal hazards of aromatic nitro compounds in actual storage and transportation processes. However, the control temperature (CT) and emergency temperature (ET), which depend on and are associated with SADT, have been rarely reported in previous studies. In this work, multiple linear regression (MLR) and artificial neural network (ANN) models for CT and ET were constructed based on the molecular descriptors corresponding to the stable structures of 27 monadic/binary aromatic nitro compounds, combined with advanced adiabatic accelerating calorimetric experiments and quantitative structure-property relationship (QSPR). The optimal subset of descriptors with significant contributions was screened out while the fit, predictive ability, and robustness of the four types of models were evaluated with internal and external validation parameters, and finally, two types of parameters (R2 and ARE) were selected as the main indicators for a comprehensive comparative analysis. The results show that the four models fit the experimental data well. During this period, the accuracy of ANN models is slightly higher than that of MLR models, and the QSPR models under the two modes (linear and nonlinear) are more inclined toward ET in prediction ability. Based on simplifying the calculation process and realizing rapid parameter prediction, this study is expected to provide technical support for engineering applications such as safe operation, safe storage and transportation of substances, and emergency response in the chemical industry. In this work, we tested and calculated the thermal safety parameters of 27 monadic/binary aromatic nitro compounds by ARC and AKTS and further used the PubChem database and Gaussian 09 software program to obtain and optimize their corresponding molecular structures. The geometric optimization process adopts DFT on the B3LYP level and the 6-31 + G(d, p) basis set, while the same functional and basis set was used for vibration analysis. The OpenBabel toolbox and ChemDES platform were used for transformation coding and descriptor calculation. Finally, IBM SPSS Statistics 24 and MATLAB software were used to construct MLR models and ANN models, respectively.

Extractive Spectrophotometric Determination and Theoretical Investigations of Two New Vanadium(V) Complexes.

Two new vanadium (V) complexes involving 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR) and tetrazolium cation were studied. The following commercially available tetrazolium salts were used as the cation source: tetrazolium red (2,3,5-triphenyltetrazol-2-ium;chloride, TTC) and neotetrazolium chloride (2-[4-[4-(3,5-diphenyltetrazol-2-ium-2-yl)phenyl]phenyl]-3,5-diphenyltetrazol-2-ium;dichloride, NTC). The cations (abbreviated as TT+ and NTC+) impart high hydrophobicity to the ternary complexes, allowing vanadium to be easily extracted and preconcentrated in one step. The complexes have different stoichiometry. The V(V)-HTAR-TTC complex dimerizes in the organic phase (chloroform) and can be represented by the formula [(TT+)[VO2(HTAR)]]2. The other complex is monomeric (NTC+)[VO2(HTAR)]. The cation has a +1 charge because one of the two chloride ions remains undissociated: NTC+ = (NT2+Cl-)+. The ground-state equilibrium geometries of the constituent cations and final complexes were optimized at the B3LYP and HF levels of theory. The dimer [(TT+)[VO2(HTAR)]]2 is more suitable for practical applications due to its better extraction characteristics and wider pH interval of formation and extraction. It was used for cheap and reliable extraction-spectrophotometric determination of V(V) traces in real samples. The absorption maximum, molar absorptivity coefficient, limit of detection, and linear working range were 549 nm, 5.2 × 104 L mol-1 cm-1, 4.6 ng mL-1, and 0.015-2.0 μg mL-1, respectively.

Chemical, Pharmacological, and Theoretical Aspects of Some Transition Metal(II) Complexes Derived from Pyrrole Azine Schiff Base.

Some new transition metal complexes were prepared by reacting metal(II) salts with Schiff base azines, which were prepared via condensation of 5-(diethylamino) salicylaldehyde and hydrazine with pyrrole-2-carbaldehyde. Their structures were confirmed based on CHN, UV-visible, FT-IR, and EPR measurements. The complexes were also assessed for their antibacterial, antioxidant, and anticancer properties. Some of these chemicals were said to be extraordinarily effective in this respect. The antibacterial activities of the complexes in vitro demonstrated their potential, although the [Cu(L)(bpy] complex was suggested to exhibit moderate activity against pathogens compared to all other in this series. The cytotoxic activity of the prepared analogues showed better cell viability compared with standard cisplatin. Moreover, there is a good agreement between the experimental and theoretical findings from docking and theoretical investigations done using DFT at the B3LYP level.

Theoretical Investigation of Structural, Spectroscopic (IR, 1H and 13C NMR), Static, and Frequency-Dependent Nonlinear Optical Properties of 4-[(1E)-3-(4-Methoxyphenyl)-3-Oxoprop-1-en-1-yl]Phenyl 4-Methylbenzene-1-Sulfonate

The present study reports the theoretical investigations of nonlinear optical properties of chalcone derivative namely 4-[(1E)-3-(4-methoxyphenyl)-3-oxoprop-1-en-1-yl]phenyl 4-methylbenzene-1-sulfonate (4MPMS). Density functional theory calculations on the geometry optimization, vibrational spectrum, 1H and 13C NMR chemical shifts, frontier molecular orbitals energies, and nonlinear optical properties are carried out by using B3LYP level in conjunction with 6–311++G(d,p) basis set. The static and frequency-dependent nonlinear optical properties (polarizability (α), anisotropy of polarizability (Δα), first and second-order hyperpolarizabilities (β and γ)) are investigated by using B3LYP level. The static NLO parameters (β(0;0,0) and γ(0;0.0.0)) were calculated as 16.240 × 10−30 and 213.77 × 10−36 esu. The second harmonic generation (SHG) β(-2w,w,w) and γ(-2w,w,w,0) parameters for the title molecule are found to be 213.97 × 10−30 esu and 485.90 × 10−36 esu, respectively. So, the frequency-dependence of β and γ parameters is clear. The obtained results demonstrated that there is a frequency dependence on the nonlinear optical properties of 4MPMS, and the title molecule is a possible candidate for first and second-order nonlinear optical materials.

Quantum chemical analysis of amino acids as anti-corrosion agents

Abstract Anti-corrosion properties of L-lysine (Lys), S-methyl (S-Met), L-cysteine (Cys), L-glycine (Gly), valinin (Val), and L-glutamine (Glu), all of which are amino acids, were evaluated on the surfaces of iron, copper, and aluminum in both the protonated and non-protonated states in both the gas and aqueous phases at their optimal symmetry. Analysis was performed based on density functional theory (DFT) calculation at 6-311++G(d,p) and B3LYP level. Monte Carlo simulation generated top and side views of the most energetically stable configuration for the adsorption of all selected amino acids on Al (110), Fe (110), and Cu (110). This suggests that the Monte Carlo simulation was able to accurately predict the adsorption properties of the amino acids on the selected metal surfaces. Glu was found to be the strongest inhibitor amongst the six molecules tested, as it had the lowest energy difference and the highest reactivity, according to the decreasing sequence of ∆E values. Electronegativity difference of the compounds investigated from highest to lowest is Lys, S-Met, Cyst, Gly, Val, and Glu. This order is also reflected in the polarizability of the compounds, with Lys having the highest polarizability and Glu having the lowest, suggesting that Glu may have the highest inhibitory efficacy.

Amino pyridine derivatives as new corrosion inhibitors for protection cabling metal of crude oil well during acidizing

Acidizing, which is essential in crude oil wells, improves oil/gas flow by injecting acid chemicals. HCl is frequently used to increase production. Add inhibitor chemicals to reduce acid stimulation and metal corrosion. Oil and gas well corrosion is successfully inhibited by amphiphilic amino pyridine derivatives. In this study, three cationic amphiphilic amino pyridine derivative inhibitors were synthesized and evaluated by FT-IR and 1H NMR analysis. These inhibitors exhibit cost-effective, eco-friendly, and highly effective inhibition reactivity for corrosion prevention. The surface activity was evaluated at 250,400 and 60 °C in 1 mol HCl, where CMC values increase and surface tension decreases as temperature increases. The corrosion inhibition efficacy (%ηw) was determined using gravimetric methods at various temperatures of 250,550, and 70 °C which revealed that SAHBR has a higher efficacy (94.5% at 25 °C, 92.3% at 55 °C and 91.1% at 70 °C) than SADBR (92.9% at 25 °C, 90.5% at 55 °C and 88.4% at 70 °C) and SAOBR (91.6% at 25 °C, 89.7% at 55 °C and 87.0% at 70 °C) for 400 ppm dose. Also, the inhibition efficacy (%ηp) which determined through potentiodynamic polarization technique which display SAHBR is 95.90% higher than SADBR is 93.90% and SAOBR is 89.90% at 25 °C for 400 ppm dose and electrochemical impedance spectroscopy (EIS) practice which parade the inhibition efficacy (%ηE) of the synthesized inhibitors where SAHBR is 91.7% higher than SADBR is 89.0% and SAOBR is 87.3% at 25 °C for 400 ppm dose. Density Functional Theory (DFT) computed quantum chemistry parameters using B3LYP level, 6-311G+ (d, p) basis sets. Calculations included EHOMO, ELUMO energies, energy gap (ΔE), softness (σ), chemical hardness (η), electrophilicity (ω), electronegativity (X), and electron transfer (ΔN) to validate amphiphilic inhibitors' inhibition properties. Molecular Dynamics Simulation (MDS) ensured system equilibrium.

The reaction of pristine and Rh-doped SnO2 clusters with acetone: Application of Evans-Polanyi principle to transition state theory.

Using transition state theory, acetone sensing by pristine and rhodium-doped tin dioxide is discussed. The Evans-Polanyi principle is modified from its original formulation commensurate with the Arrhenius equation to be more suitable for transition state theory. The new formalism for the activation energy replaces enthalpy with Gibbs free energy in the original Evans-Polanyi principle. The new formalism considers reaction entropy, which is not considered previously in Evans-Polanyi principle. Response and response time of interaction of acetone with both pristine and Rh-doped SnO2 clusters is calculated. Variations of response in terms of acetone concentration and temperature are calculated and compared to the experiment. Acceptable agreement between theory and experiment that calls for more comparisons to demonstrate the modified approach. The pristine and Rh-doped clusters and their interaction with acetone are simulated using density functional theory at the B3LYP level. 6-311G** and SDD (for heavy atoms) basis sets are used to optimize the structures examined in the present work. Gaussian 09 program and accompanying software performed the current tasks.

Novel 1,3‐diphenyl‐4‐(N,N‐dimethylimido dicarbonimidic diamide azo)‐5‐pyrazolone and its chelates with manganese, nickel, copper, and zinc divalent metal ions as an antibacterial activity supported by molecular docking studies: Design, synthesis, DFT, and TD‐DFT/PCM calculations

A novel 1,3‐diphenyl‐4‐(N,N‐dimethylimidodicarbonimidic diamide azo)‐5‐pyrazolone as a ligand, simplified as DNP, and its chelates were prepared. Characterization of the structures was performed based on several analytical and spectroscopic techniques. To support these studies, density functional theory (DFT) calculations were carried out by using the B3LYP level, B3LYP/6‐311G** level for the free ligand, and B3LYP/6‐311G**‐LANL2DZ functional level for the solid chelates. The acquired results indicated that DFT calculations generally give compatible results with the experimental ones. Hyper conjugative interactions, molecular stability, bond strength, and intramolecular charge transfer were examined by applying natural bond orbital (NBO) analysis. Nonlinear optical properties of the obtained compounds were investigated by determining molecular polarizability (α), and hyperpolarizability (β) parameters provided a hint for the synthesized compounds' intriguing optical characteristics. The electronic structure of the ligand and its complexes were predicted using the time‐dependent DFT (TD‐DFT) method with a polarizable continuum model (PCM) exploiting the B3LYP approach combined with a 6‐31G(d,p) basis set. The prepared compounds' antibacterial activity was experimentally verified utilizing the agar well diffusion method versus selected G + and G‐ bacteria. The molecular docking mechanism between the bacterially resistant chelates and their inhibited bacteria protein pocket receptors was carried out to determine the modes that these compounds bind to the protein's active sites.

Enriching the electronic populations of D-π-A type ON-OFF solar switches with sp2 hybridization: A TD-DFT possibility to create pull-push effect

The ability of specific molecular acceptors in photovoltaic devices is determined by their structure and chemical composition. Multiscale computations are important to protect investigation design; hence, efforts and money could be saved. Using Density Functional Theory (DFT), the effect of sp2 hybridized nitrogen substitutions (Ns) at the specific positions of a solar cell dye, 2,2′-((4-heptyl-4,9,9-trihexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(methanylylidene)bis(3-oxo-2,3-dihydro-1H-indene-1-yl-2-ylidene)dimalononitrile (IDIC), is explored. The N-incorporated dyes (IDIC1-IDIC5) were optimized at their ground energy minima at the B3LYP level of DFT with 6-31G+(d,p) basis sets. From these optimized geometries, their UV–visible analysis was executed at the DFT functional of CAM-B3LYP/6-31G+(d,p) selected as a result of benchmarking their λmax values with experimental values of IDIC. The computed value was found to be 528 nm which was very near to its experimental value (540 nm). Interestingly, for all the new dyes, λmax had blue-shifted values of (502–513 nm) for IDIC1, IDIC2 and IDIC5 and red-shifted values (557–779 nm) for IDIC3 and IDIC4 as compared to IDIC. The highest second-order Non-Linear Optical (NLO) response of 1054 e.s.u was noted for IDIC4 and IDIC5 which had the lowest energy gaps. It was found that incorporating Ns has significantly decreased the energy gap of electron rearrangement.

Redox-Regulated Magnetic Conversions between Ferro- and Antiferromagnetism in Organic Nitroxide Diradicals.

Redox-induced magnetic transformation in organic diradicals is an appealing phenomenon. In this study, we theoretically designed twelve couples of diradicals in which two nitroxide (NO) radical groups are connected to the redox-active couplers including p-benzoquinonyl, 1,4-naphthoquinyl, 9,10-anthraquinonyl, naphthacene-5,12-dione, pentacene-6,13-dione, hexacene-6,15-dione, pyrazinyl, quinoxalinyl, phenazinyl, 5,12-diazanaphthacene, 6,13-diazapentacene, and 6,15-diazahexacene. As evidenced at both the B3LYP and M06-2X levels of theory, the calculations reveal that the magnetic reversal can take place from ferromagnetism to antiferromagnetism, or vice versa, by means of redox method in these designed organic magnetic molecules. It was observed that p-benzoquinonyl, 1,4-naphthoquinyl, 9,10-anthraquinonyl, naphthacene-5,12-dione, pentacene-6,13-dione, and hexacene-6,15-dione-bridged NO diradicals produce antiferromagnetism while their dihydrogenated counterparts exhibit ferromagnetism. Similarly, pyrazinyl, quinoxalinyl, phenazinyl, 5,12-diazanaphthacene, 6,13-diazapentacene, and 6,15-diazahexacene-bridged NO diradicals present ferromagnetism while their dihydrogenated counterparts show antiferromagnetism. The differences in the magnetic behaviors and magnetic magnitudes of each of the twelve couples of diradicals could be attributed to their distinctly different spin-interacting pathways. It was found that the nature of the coupler and the length of the coupling path are important factors in controlling the magnitude of the magnetic exchange coupling constant J. Specifically, smaller HOMO-LUMO (HOMO: highest occupied molecular orbital, LUMO: lowest unoccupied molecular orbital) gaps of the couplers and shorter coupler lengths, as well as shorter linking bond lengths, can attain stronger magnetic interactions. In addition, a diradical with an extensively π-conjugated structure is beneficial to spin transport and can effectively promote magnetic coupling, yielding a large |J| accordingly. That is, a larger spin polarization can give rise to a stronger magnetic interaction. The sign of J for these studied diradicals can be predicted from the spin alternation rule, the shape of the singly occupied molecular orbitals (SOMOs), and the SOMO-SOMO energy gaps of the triplet state. This study paves the way for the rational design of magnetic molecular switches.

Bioinformatic analysis of highly consumed phytochemicals as P-gp binders to overcome drug-resistance.

P-glycoprotein (P-gp) is an adenosine triphosphate (ATP)-dependent membrane efflux pump for protecting cells against xenobiotic compounds. Unfortunately, overexpressed P-gp in neoplastic cells prevents cell entry of numerous chemotherapeutic agents leading to multidrug resistance (MDR). MDR cells may be re-sensitized to chemotherapeutic drugs via P-gp inhibition/modulation. Side effects of synthetic P-gp inhibitors encouraged the development of natural products. Molecular docking and density functional theory (DFT) calculations were used as fast and accurate computational methods to explore a structure binding relationship of some dietary phytochemicals inside distinctive P-gp binding sites (modulatory/inhibitory). For this purpose, top-scored docked conformations were subjected to per-residue energy decomposition analysis in the B3LYP level of theory with a 6-31g (d, p) basis set by Gaussian98 package. Consecutive application of computational techniques revealed binding modes/affinities of nutritive phytochemicals within dominant binding sites of P-gp. Blind docking scores for best-ranked compounds were superior to verapamil and rhodamine-123. Pairwise amino acid decomposition of superior docked conformations revealed Tyr303 as an important P-gp binding residue. DFT-based induced polarization analysis revealed major electrostatic fluctuations at the atomistic level and confirmed larger effects for amino acids with energy-favored binding interactions. Conformational analysis exhibited that auraptene and 7,4',7'',4'''-tetra-O-methylamentoflavone might not necessarily interact to P-gp binding sites through minimum energy conformations. Although there are still many hurdles to overcome, obtained results may propose a few nutritive phytochemicals as potential P-gp binding agents. Moreover; top-scored derivatives may have the chance to exhibit tumor chemo-sensitizing effects.

Quantum mechanical approaches and molecular docking studies of metal based anticancer drugs cis-Diammine glycolato platinum and Diaminocyclohexane oxalatoplatinum structures

The optimized structures and theoretical studies of metal based anticancer drugs Nedaplatin (cis-Diammine glycolato platinum) (CDGP) and Oxaliplatin (Diaminocyclohexane oxalatoplatinum) (DCOP) structures by Density Functional Theory (DFT) method at the B3LYP level with LANL2DZ was applied to investigate the spectroscopic, structural optical properties, conducting properties for the chosen materials, Band Gap was predicted with the help of HOMO-LUMO values. From the calculated parameters of the title compounds CDGP and DCOP shows DCOP found to be highly reactive metal complexed anticancer drug over CDGP. On calculating the site of the lowest binding energy a receptor active site with ligand is done by Ligand-protein docking process. In this study, the difference in the coordinates of ligands and the binding (intermolecular) energy called as Root Mean Square Deviation (RMSD) estimated to estimate the drug-DNA interactions. Molecular docking is the broadly used screening studies in the visualizing of Drug–DNA interaction at an level of atom and drug designing based on structure. Chosen anticancer drugs with their binding affinities to the selected DNA and Drugs potential anticancer behavior were examined, Out of 2 drug compounds screened, CDGP and DCOP, DCOP have shown least binding energies as −6.88 kcal/mol than CDGP as −5.64 kcal/mol and the interactive studies of drug compounds conformations with RMSD values in accordance to crystal structures is less than or equal to 2.00 Å in focusing on the complete DNA structure (large grid box) done using the Autodock software.The compound with most least binding energy value with low inhibition constant found to have good binding affinity towards the DNA structure and the structural properties studied using DFT also shows good chemical reactivity in accordance with the Docking studies.From the results obtained DCOP found to have good chemical descriptors with Good binding affinity than CDGP.Thus DCOP is the best suited for biological molecular target.

Spectral Elucidations and Molecular Docking Analysis of Hydrogen Bonded Coordination Metal Complex Cadmium Nicotinate Using DFT Method

The geometry optimization, natural bond orbital analysis, and vibrational analysis of Cadmium Nicotinate (CdN) were performed using the density functional B3LYP level with a LANL2DZ basis set. Transfer of electrons from the lone pair oxygen in COO− to the antibonding orbital of the O-H bond results in the formation of hydrogen bonds, which results in the most interesting biological properties, according to natural bond orbital analysis. The red shift in wavenumber has been confirmed by intramolecular O-H…O hydrogen bonding interactions and the water group coordinated to the central metal cadmium via oxygen atoms. UV spectral analysis, on the other hand, reveals the n→π* transition due to its strong peak in absorption spectra, demonstrating its biological activity. The MEP and Fukui Functions are used to represent the molecule’s reactive region, which remains more electrophilic around the oxygen atoms. DOS spectral analysis is used to investigate the molecular orbital contributions. The Electron Localization Function (ELF) and the Local orbital locator (LOL) were used to conduct topological studies on CdN. To investigate distinct covalent and non-covalent interactions, Hirshfeld surface analysis and reduced density gradient analysis were used. Molecular docking studies were used to investigate ligand-protein interactions and ADME parameter analysis and the Lipinski rule for the CdN molecule confirmed that the compound has good drug-like properties and could be developed as an antifungal drug in the future.

Hydrolysis Reactions of the High Oxidation State Dimers Th2O4, Pa2O5, U2O6, and Np2O6. A Computational Study.

The energetics of the hydrolysis reactions for high oxidation states of the dimeric actinide species Th2IVO4, Pa2VO5, and U2VIO6 were calculated at the CCSD(T) level and those for triplet Np2VIO6 at the B3LYP level. Hydrolysis is initiated by the formation of a Lewis acid/base adduct with H2O (physisorbed product), followed by a proton transfer to form a dihydroxide molecule (chemisorbed product); this process was repeated until the initial actinide oxide is fully hydrolyzed. For Th2O4, hydrolysis (chemisorption) by the initial and subsequent H2O molecules prefers proton transfer to terminal oxo groups before the bridge oxo groups. The overall Th2O4 hydration pathway is exothermic with chemisorbed products preferred over the physisorption products, and the fully hydrolyzed Th2(OH)8 can form exothermically. Hydrolysis of Pa2O5 forms isomers of similar energies with no initial preference for bridge or terminal hydroxy groups. The most exothermic hydrolysis product for Pa is Pa2O(OH)8 and the most stable species is Pa2O(OH)8(H2O). Hydrolysis of U2O6 and Np2O6 with strong [O═An═O]2+ actinyl groups occurs first at the bridging oxygens rather than at the terminal oxo groups. The U2O6 and Np2O6 pathways predict hydrated products to be more favored than hydrolyzed products, as more H2O molecules are added. The stability of the U and Np clusters is predicted to decrease with increasing number of hydroxyl groups. The most stable species on the hydration reaction coordinate for U and Np is An2O3(OH)6(H2O).

Thermodynamic properties of benzotriazole derivatives: An experimental and computational study

A thermochemical study of 5-methyl-1H-benzotriazole and 5,6-dimethyl-1H-benzotriazole was carried out experimentally using calorimetric techniques and an effusion method. Parallel to that, a computational methodology was also applied. The massic energies of combustion and the enthalpies of sublimation were determined from static bomb combustion calorimetry and Knudsen mass-loss effusion method and/or high-temperature Calvet microcalorimetry, respectively. From these experimental data, the standard molar enthalpies of formation of the two benzotriazoles in the gaseous phase were derived. Additionally, the gas-phase enthalpies of formation of these benzotriazoles and other two methylated derivatives were calculated using the G3(MP2)//B3LYP level of theory. The data obtained allowed the study of the energetic effects associated with the presence of a methyl group in the benzotriazole structure and their comparison with identical effects in homocyclic molecules, namely benzene and naphthalene. The Gibbs energies of formation of the compounds in the crystalline and gaseous phases were also determined to assess their thermodynamic stability.

In silico design based on quantum chemical, molecular docking studies and ADMET predictions of ciprofloxacin derivatives as novel potential antibacterial and antimycrobacterium agents

Drug designing and development is an important area of research for pharmaceutical companies and chemical scientists. In this paper, we report the prediction of new ciprofloxacin derivatives by quantum chemical, molecular docking studies and pharmacokinetic properties. Theoretical studies were performed by geometry optimization computation using B3LYP level at 6-311 G (d,p) basis set. The absorption, distribution, metabolism, excretion and toxicity (ADMET) parameters were predicted and the result show that all compounds have a great ADMET profile. To study the antibacterial, anti-Mycobacterium tuberculosis activities, ciprofloxacin and its derivatives were interacted with the proteins: Thymidylate Kinase (PDB: 4QGG), Biotin carboxylase (PDB: 3JZF) and β-lactamase BlaC (PDB: 3N7W). The results of the docking studies indicate that one pharmacophore designed presents a great inhibition behavior against gram-positive organism (4QGG) and significant interactions observed between the compound and ARG48, GLN101, ARG105 and GLU37 residues of 4QGG. Also, another derivative designed present the best inhibition against gram-negative organism (3JZF) several interactions were noticed between the compound and GLY165, ILE287, LEU278, HIS236, HIS209, MET169 and LYS159 residues of (3JZF). As well as, one designed candidate is good inhibitors for β-lactamase (3N7W) multiple no bonded interactions were observed between the compound and SER84, ILE117, ASN186, LYS87, ARG187, ASN186 and THR251 residues of(3N7W). Molecular dynamics (MD) simulation study was also performed for 100 ns to confirm the stability behaviour of the main protein and inhibitor complexes. The MD simulation study validated the stability of three compounds in the protein binding pocket as potent binders. Natural bonding orbital analysis, reactivity indices and molecular electrostatic potential were carried out. The research finding of this study can be helpful to design a new potent antibacterial, antimycrobacterium candidate’s drugs that will serve as the basis for future in vitro and in vivo research. Communicated by Ramaswamy H. Sarma

2,3-Diarylquinoline -Based Iridium (III) Complexes: Synthesis, Photophysical Properties and DFT studies

Phosphorescent transition–metal complexes have received considerable interest in the development of efficient organic light-emitting diodes (OLEDs). Iridium complexes derived from heterocyclic ligands have brought a paradigm shift in the optoelectronic materials. Quinoline-based molecular architectures offer excellent materials for such applications due to their exceptional electronic properties, extended π-conjugation and strong ligand–metal binding. Iridium complexes of 2,3-diaryl quinolines with electron rich and electron deficient substituents were synthesized and their electronic properties were studied. Iridium complexes Ir1 and Ir2 bearing the electron withdrawing (-CF3) and electron donating (–OCH3) groups, respectively at the para position of the 2-phenyl ring of 2,3-diarylquinoline exhibited prominent absorption bands in the UV range. Further, the complex Ir3 with unsubstituted 2,3-diarylquinoline ligand and CF3 containing Ir1 showed intensive red phosphorescence near 603 and 611 nm, respectively due to metal-to-ligand and ligand-to-ligand (MLCT/LLCT) charge transfer characteristics. The photoluminescence (PL) spectra of the Ir4 complex derived from 2-phenylquinoline ligand exhibited a bright yellow phosphorescent emission at 589 nm. An additional C3 aryl group on the quinoline ring resulted in a red shift in the emission wavelength of Ir1 and Ir3 complexes compared to Ir4. The PL spectra of Ir2 on the other hand was weak, and blue-shifted to 489 nm, which can be attributed to a ligand-centered (LC) transition. The complexes showed photoluminescence quantum yield (PLQY) in the range of 0.004 to 0.17 and fluorescence lifetime ranged from 1.5 ns to 399 ns, implying the significant effect of the ligand structure on the properties of the complexes. Photophysical investigation of the complexed affirms these complexes to be potent materials for OLEDs fabrication. Cyclic voltammetry was used to investigate the electrochemical characteristics of Ir1-Ir4 complexes in acetonitrile. All of the complexes Ir1-Ir4 exhibited irreversible oxidation waves at 0.44 V, 0.23 V, 0.25 V, and 0.24 V respectively. Ir1-Ir4 complexes showed a reduction potential at −0.98 V, −0.96 V, −1.02 V and −0.97 V respectively. The DFT calculations were used to explore HOMO-LUMO energies, and NBO characteristics by B3LYP level of theory using ECP type double zeta (DZ) quality basis set LanL2DZ for metal and 6-311G(d) basis sets for non-metal atoms. The theoretical calculations were in significant agreement with the experimental studies of these complexes.