Basis Set Level Research Articles

Density Functional Theory Investigation For Ni6, Co5, Au12, Y5 and Ni6Li, Co5Li, Au12Li, Y5Na Interactions

Geometry optimization for pure transition metals structures Ni6 , Co5 , Au12 , Y5 and alkali-transition metals structures Ni6Li , Co5Li , Au12Li , Y5Na at B3LYP level, 3-21G and LaNL2DZ basis sets has been investigated by using Density Functional Theory (DFT) throughout Gaussian09 package. Electrostatic potential,contours, infrared spectra, symmetry, energy gap has been studied for all structures. Total energy for pure transition metals structures is greater than the total energy for alkali-transition metals structures, One can say that the orbitals that generate between Lithium and atoms of pure Nickel structure will be from anti-bonding type. Dipole moment for some pure Nickel structure has zero value because it is homostructure, the other pure transition structures has nonzero values although they are homostructures this is result because of the geometry structures, but the dipole moment for all alkali-transition structures has nonzero numerical values because it is hetrostructures. Energy gap for Y5Na is the smallest value of energy gaps of the structures under study, it approaches to the energy gap of GaAs, this property is very useful in electronic applications such as manufacturing of processors of laptops, Eg of Y5Na = 0.95 eV, Eg of GaAs = 0.8 eV.

Guided Ion Beam Studies of the Dy + O → DyO+ + e– Chemi-ionization Reaction Thermochemistry and Dysprosium Oxide, Carbide, Sulfide, Dioxide, and Sulfoxide Cation Bond Energies

Guided ion beam tandem mass spectrometry (GIBMS) was used to measure the kinetic energy dependent product ion cross sections for reactions of the lanthanide metal dysprosium cation (Dy+) with O2, SO2, and CO and reactions of DyO+ with CO, O2, and Xe. DyO+ is formed through an exothermic process when Dy+ reacts with O2, whereas all other processes observed are found to be endothermic. The kinetic energy dependences of these cross sections were analyzed to yield 0 K bond dissociation energies (BDEs) for DyO+, DyC+, DyS+, DyO2+, and DySO+. The 0 K BDE for DyO+ is determined to be 5.60 ± 0.02 eV from the weighted average of six independent thresholds, which are dominated by the slightly endothermic reaction of Dy+ with SO2. Combined with the well-established Dy ionization energy (IE), this value indicates that the chemi-ionization reaction, Dy + O → DyO+ + e-, is endothermic by 0.33 ± 0.02 eV. Theoretical BDEs for Dy+-O, Dy+-C, Dy+-S, ODy+-O, and Dy+-SO were calculated at several levels of theory and basis sets for comparison with experiment with reasonable agreement achieved.

Evolving the complexities of glycine magnesium chloride (GMC) crystal through DFT computation for NLO utilizations

A new grown seed's of GMC (Gylcine Magnesium Chloride) are cultivated by slow evaporation technique. Thus grown seeds are developed as a single large crystal within certain temperature conditions into modified dimensions. The lattice boundaries of the crystal were confirmed by SXRD (Single Crystal X-Ray Diffraction) method. FTIR (Fourier Transform Infrared) and UV–VIS-NIR spectrums are used for probing the structural and molecular properties through transmission and absorption of spectrum. The molecular structure of GMC is computed using DFT. Linear and non linear optical properties are calculated with the aid of Gaussian 09 by DFT/B3LYP/CC-PVTZ level of theory software. Through this computation method we had calculated MEP (Molecular Electrostatic Potential) to investigate the mole positions and the charge distributions. HUMO AND LUMO studies also done to know about the electron donor and acceptor characteristics of the GMC further DOS (Density Of States) of the compound was also calculated as spectrum of Gauss sum. The National Bond Orbital Population Analysis (NBO) was carried out for computing the bond strength between the molecules by using the Gaussian B3LYP/6–311++ G (d,p) level of basis set. The Mulliken Charge Analysis (MCA) confirms the atom distributions with different negative and positive potential in reference with the total electron density surface. This studies reveals that GMC as Non-linear characteristics over linear thus it can be applied for optical device fabrications.

Computational studies on sulfonamide drug molecules by density functional theory

This paper reports the complete theoretical investigation of Sulfonamide drugs namely Sulfadiazine (SDZ), Sulfamerazine (SMZ) and Sulfamethazine (SMZ) using the Density functional theory (DFT) at B3LYP, CAM-B3LYP and B3PW91 level of theories with 6-311++G(d,P) basis set. The geometrical parameters namely bond lengths and bond angles are computed and compared with the literature values. The frontier molecular orbitals (FMO) have been computed. In addition, the global reactivity descriptors have been calculated using FMO to shine a light on the chemical reactivity and stability of titled molecules. The molecular electrostatic potential (MEP) study has been used to find out the preferred sites for electrophilic and nucleophilic attacks in the titled molecules. The Mulliken atomic charge distribution has been carried out at same level of theories and basis set. The NLO optical parameters have been computed for titled molecules to check their candidature for NLO applications. The assignment of FT-IR spectra of titled molecules has been carried out by potential energy distribution (PED) using the VEDA software. Natural bonding orbitals (NBO) are computed and used to identify the most possible intensive intermolecular interactions.

Experimental and theoretical calculation of pKa values of substituted-2,4,6-trinitrodiphenylamines

The pKa values of eighteen 2,4,6-trinitrodiphenylamine derivatives were determined experimentally from their UV–vis spectra and their values were also calculated using quantum chemical methods. The accuracy of the various levels of theory and basis sets were assessed using the solvation model based on density and conductor-like screening model. Linear correlation coefficients of the calculated pKa values are in the range 0.44 – 0.89, 0.11 – 0.90 and 0.43 – 0.90, when compared with those obtained experimentally, for the 6-311++G(d,p), 6-31+G(d,p) and 6-31G(d) basis sets respectively. Increasing the size of the basis set by adding polarization and diffuse functions increase the average errors in the calculations, for ωB97XD functional in acetonitrile. Such variation was not observed in other functionals. Furthermore, the mean signed errors (MSE) for calculations with semiempirical methods are highly comparable but with very poor linear correlation coefficients. The M06-2X functional, in combination with the 6-31+G(d,p), 6-311++G(d,p) and 6-31G(d) basis sets, gave a much better performance than the other functionals used in the present study. The effect of empirical dispersion in the PM6-DH + method was not significant, as the results are similar to those obtained with AM1 and PM7. A strong correlation was observed for the pKa values obtained experimentally with Hammett σ constants, CN bond lengths and charges.

Design, Synthesis of Some Innovative Indolo[3,2-c]Isoquinoline-5-One Analogs and Associated Bioactivities, Pharmacophore, Molecular Docking, MEP, and Conceptual DFT Studies

A series of novel triazolothiadiazolethione and triazolothiadiazine appended indolo[3,2-c]isoquinoline-5-one were designed, synthesized, and validated by IR, 1H, 13C NMR, and mass spectroscopy strategies. All compounds are determined by their DFT investigations with B3LYP/def2-TZVP basis set level, ionization potentials, and electron affinities at vertical (IPv and EAv) and adiabatic parameters (IPA and EAA). Compound 3a has demonstrated the greatest values for these parameters. The compounds’ HOMO-LUMO (FMOs) and MEP maps were performed. The optimized structure of the compounds was estimated in global hardness, softness, global electrophilicity, and dipole moment. To find new drug candidates, different in vitro biological activities were implemented employing antimicrobial activity: Gram-negative bacteria were significantly suppressed by compound 4a, whereas gram-positive bacteria were strongly inhibited by compounds 3c and 3a has significant antifungal and anticancer effects. Compound 4b is profoundly antioxidant with IC50 value of 8.74 ± 1.93 µg/mL and MIC value of 0.25 µg/mL for antituberculosis properties. Thereafter, all of the compounds were subjected to e-pharmacophore approach to molecular docking studies. Compound 4a exhibited the best docking score (−8.458 kcal/mol) and docking interactions with active binding sites of 1TL8 receptor.

Efficiency of C = Se as hydrogen bond acceptor in controlling regioselective amination of 5,7-dinitroquinazoline-4-selenone: Quantum mechanical, AIM and docking analysis by density functional method

Herein, we explored the theoretical aspect of reaction between 5,7-dinitroquinazoline-4-selenone and methylamine by employing density functional theory (DFT) calculations. The energetic parameters confirmed that the reaction progressed via. concerted mechanism with the single step process instead of two step process via intermediate formation. Further, role of Se = C bond as non-conventional H-bond acceptor is reported in reaction controlling factors that monitors the regioselectivity of the present proposed reaction. Despite of substantial steric hindrance at ortho-position of 5,7-dinitroquinazoline-4-selenones, the regioselective amination resulted into ortho-substituted product (P2) rather than para-substituted product (P1) attributed to non-conventional NH---Se = C intramolecular hydrogen bonding. The topological properties of the electron density distributions have been studied by using quantum theory of atoms in molecules (QTAIM). The presence of non-conventional hydrogen bond acceptor–donor interactions (NH---Se = C) in ortho-positioned amination is achieved by electron density ρ(r) and Laplacian of electron density ∇2ρ(r) in QTAIM analysis and supported the results of DFT studies hybrid with B3LYP/6-31G(d,p) basis set. Due to the lack of intramolecular hydrogen bonding interactions (NH---Se = C), the para-positioned amination on 5,7-dinitroquinazoline-4-selenone is founded to be less feasible. Further, the DFT technique has been used to investigate frontier molecular orbital (FMO) analysis and global reactive parameters using the aforesaid level of theory and basis set. HOMO-LUMO analysis revealed that ortho-substituted product (P2) has a wider energy gap (3.0684 eV) than para-substituted product (P1) (2.6402 eV) suggesting more stability of P2. The presence of hydrogen bonding interactions is further confirmed by the change in electrostatic potential regions in ortho-substituted product (P2) as compared to reactants in molecular electrostatic potential surface (MEPS) studies. Both para-substituted product (P1) and ortho-substituted product (P2) have been docked into the protein 5FCT's active site to predict favored binding location, activity and affinity by using docking studies.

Molecular Structure, Vibrational Studies and Reactivity Descriptors Analysis of 4-[2-(tert-butylamino)-1-hydroxyethyl]-2-(hydroxymethyl)Phenol

The compound 4-[2-(tert-butylamino)-1-hydroxyethyl]-2-hydroxymethyl)phenol (4BAHEHMP)was chosen for investigation and characterized by FT- IR and FT- Raman spectral analysis. The compound has been studied significantly by using density functional theory (DFT) calculations by the B3LYP method at the 6-31++G(d,p) basis set level. The calculated results show that the structural parameters can be reproduced well with the predicted geometry. The experimental vibrational frequencies were compared with the scaled vibrational frequencies for the assignment of vibrational bands. In addition to the DFT calculations of the compound, the calculations were performed for Fukui functions to explain the chemical selectivity or reactivity sites such as the molecule's nucleophilic, electrophilic, and radical attack in the compound. Mulliken atomic charges are calculated for the determination of electronic charge distribution and reactive sites which proves the formation of intermolecular interaction in solid forms provided by the significant region of electronegativity around oxygen atoms and the net positive on hydrogen and nitrogen atoms.The chemical and thermal stability of the compound is studied by using DFT method for different temperatures and it shows that thermodynamic parameters increase with increase in temperature. HIGHLIGHTS Vibrational spectra (FT-IR and FT-Raman) of the title molecule were analysed with DFT supported computational technique Reactive regions of the title compound were reported using MEP and Fukui function studies The chemical and thermal stability of the compound was computed by using DFT method for various temperatures and it shows that thermodynamic parameters increase with increase in temperature GRAPHICAL ABSTRACT

Structural investigations and theoretical insights of a polymethoxy chalcone derivative: Synthesis, crystal structure, 3D energy frameworks and SARS CoV-2 docking studies

Chalcone derivatives with various functional groups have shown potent pharmacological and non-linear optical properties. A multi‑methoxy substituted (E)-1-(3,4-dimethoxyphenyl)-3-(3,4,5-trimethoxyphenyl) prop‑2-en-1-one, chalcone derivative has been synthesized and spectroscopically characterized by 1H and 13C NMR, LC-MS and FT-IR techniques. A pale yellow colored rectangular shaped single crystals of the compound were obtained by slow evaporation method and the three dimensional structure was confirmed using X-ray diffraction studies. The compound crystallized in the monoclinic crystal system with P21/a space group. The crystal and molecular structure is stabilized by CH···O inter and intra molecular hydrogen bond interactions apart from the prominent CH···π and π···π stacking interactions. These interactions were studied using Hirshfeld surface analysis to understand the nature and strength of interactions; the 2D fingerprint plot quantifies each individual intermolecular contact and revealed that the H…H (49.2%) interactions have the major contribution to the molecular surface. The analysis of 3D molecular energy frameworks revealed that the dispersion energy (-208.16 kJ mol−1) dominates all other energies and their visualization identifies the packing order of the molecules in the crystalline environment. The lattice energy of the compound is found to be -398.1 kJ mol−1. The electronic properties of the compound were quantified using theoretical quantum chemical computations with DFT-B3LYP/6–311+G (d, p) level basis set. The electronic energy band gap of the chalcone molecule is found to be 3.6961 eV. The NBO and Mulliken atomic charges were computed and the molecular electrostatic potential map was plotted to identify the chemical reactive sites on the molecular surface. The second-order nonlinear optical properties of the molecule based on the first static hyperpolarizability (β) have been investigated. Further, the molecular docking studies of the chalcone derivative against corona virus 2 (SARS-CoV-2) protein have been carried out to shed light on the possible significant molecular interactions.

Prediction of correlation energies using variational subspace valence bond.

In the variational subspace valence bond (VSVB) [G. D. Fletcher, J. Chem. Phys. 142, 134112 (2015)] method, the electronic orbitals comprising the wave function correspond to chemically meaningful objects, such as bonds, lone pairs, atomic cores, and so on. Selected regions of a molecule (for example, a single chemical bond, as opposed to all the bonds) can be modeled with different levels of basis set and possible methods for modeling correlation from the other regions. The interactions between the components of a molecule (say, a bond and a neighboring orbital) can then be studied in detail for their impact on a chemical phenomenon while avoiding the expense of necessarily applying the higher levels and methods to the entire molecule. This work presents the theoretical basis for modeling correlation effects between specific electron pairs by incorporating terms in the inter-electronic coordinates ("r12") into VSVB. The approach is validated with calculations on small systems using single-reference wave functions.

Environment-Friendly Corrosion Inhibitors for Aluminum in Hydrochloric Acid: Quantum and Experimental Research

Environment-friendly materials (e.g., Honey and Mint) are used as corrosion inhibitors for aluminum in hydrochloric acid (HCl) using both the density functional theory (DFT) at the B3LYP/6–31G* basis set level and semi-empirical methods (AM1, PM3, MINDO, and RM1). The aim of this study is to investigate the inhibition efficiency (%IE) in terms of their molecular structure. The quantum chemical parameters such as the highest occupied molecular orbital energy (EHOMO), the lowest unoccupied molecular orbital energy (ELUMO), the energy gap (ΔE), the charge on the reactive core, the hardness (η), and the total energy have all been computed. The MINDO method was used to measure the electronic energies and charge densities of the inhibitors that were used. Theoretical calculations were also carried out, with the findings correlating well with the experimental data. Gravimetry and gasometry measurements were used to investigate the effects of honey and mint on aluminum corrosion in a 1.0 M hydrochloric acid (HCl) solution. In acid solutions, honey and mint were found to be effective inhibitors of aluminum corrosion, with honey being the better option. Because of the adsorption of its components on aluminum surfaces, the inhibitory effect of the used inhibitors was addressed. The higher dipole moment of honey than that of mint caused the adsorption of honey on the aluminum surface better. The IEs measured by gravimetry and gasometry are almost identical.

Synthesis, single crystal (XRD), spectral characterization, computational (DFT), quantum chemical modelling and anticancer activity of di(p-bromobenzyl) (dibromo) (1, 10-phenanthroline) tin (IV) complex

The structure of the complex Di(p-bromobenzyldibromo) (1, 10-phenanthroline) tin (IV) complex was confirmed by experiments with infrared, Raman, NMR, and a single crystal (4BRBR). For comparing theoretical and practical methods, the DFT method was used, with the theoretical method optimised to be used for the B3LYP/LanL2DZ basis set level. A software named Multiwfn was used to perform the quantum chemical calculations. The weak interaction observed at C----H----Br were confirmed by X-ray analysis. The tin atom regular octahedral geometry can be seen in the crystal structure of the complex. The anticancer activity of this complex was studied using PC3, MCF7, U937, and U87 cells. Results show that MCF7 (breast cancer cell) has a higher anticancer activity compared to cisplatin (standard drug) and other cell lines, which is 7.8 mg/l.

Synthesis, spectral characterisations of 3t-pentyl-2r,6c-diarylpiperidin-4-one oxime picrates: DFT studies and potent anti-microbial agents

In this paper, various substituted 3t-pentyl-2r,6c-diarylpiperidin-4-one oxime picrates were synthesised and characterised by elemental analysis, FT-IR, NMR, UV–Visible and Fluorescence spectral techniques. For compound 1, NMR spectral assignments were made unambiguously by their one-dimensional (1H and 13C NMR) and two-dimensional (1H–1H COSY, NOESY, HSQC and HMBC) spectra. The observed chemical shifts and coupling constants suggest that compounds 1–7 adopt normal chair conformation with the equatorial orientation of all the substituents like aryl group at C(2) and C(6) and pentyl group at C(3). Compounds 2 and 7 exhibited potent anti-bacterial activity and fungal activity against all the tested strains while all the other compounds showed moderate activity. The molecular structure of compounds (1–7) was optimised at the density functional theory (DFT)/B3LYP/6-311++G(d,p) level of basis set. The calculated first hyperpolarisability (β 0) values show that all the molecules might have non-linear optical (NLO) behaviour. The HOMO–LUMO transition implies that intra-molecular charge transfer takes place within the molecule. The molecular electrostatic potential (MEP) surface is used to understand the reactive sites of a molecule.

Spectroscopic investigations, ab-initio DFT calculations, molecular docking and in-vitro assay studies of novel oxovanadium(V)chalcone complexes as potential antidiabetic agents

A series of four novel oxovanadium(V)chalcone complexes ([VO(LI-IV)2Cl]; where HLI=1-(2-Hydroxy-phenyl)-3-phenyl-propenone, HLII=1-(1-Hydroxy-naphthalen-2-yl)-3-phenyl-propenone, HLIII = 1-(2-Amino-phenyl)-3-phenyl-propenone, HLIV = 4-Hydroxy-6-methyl-3-(3-phenyl-acryloyl)-pyran-2-one) were designed and synthesized by performing chemical reaction between VOCl3 and respective chalcone derivatives in 1:2 molar ratio. Their formation as well as chemical structures were confirmed by FTIR, UV-Visible, 1H-NMR, SEM, EDS, and mass spectrometry spectroscopic techniques. The geometry of the synthesized complexes was purposed to be octahedral on the basis of the characterization. Further computational and structural parameters of the synthesized complexes were determined in order to establish their thermodynamic stability/chemical reactivity of the synthesized complexes. Density Functional Theory (DFT) method was employed to calculate the molecular geometry and vibrational frequencies of the synthesized complexes using B3LYP hybrid functional at 6-31G* level of basis set. Further, Spartan'20 V1.0.0 program package was used to calculate the 1H-NMR spectra with (DFT/ B3LYP) in the gaseous phase to validate the structure of oxovanadium(V) complexes. The experimentally obtained results were found to be well correlated with theoretical results with a correlation value > 0.96. Global reactivity descriptors helps to explain the bioactivity of complexes hence, were calculated from the HOMO-LUMO energies. The enzymatic assay experiments indicated that all the four synthesized complexes have significant to moderate inhibition potential against α-glucosidase, and α-amylase enzymes. Among all the oxovanadium(V)chalcone complexes, complex 4showed excellent and superior inhibition potency almost equivalent to the commercially available Acarbose drug and even better in case of α-amylase. The observed IC50 value of complex 4 for the inhibition of α-amylase and α-glucosidase was calculated to be 16.36 µg/mL and 57.27 µg/mL, respectively. The Kinetic parameters calculated from the Lineweaver-Burk plot showed that complex 4 were uncompetitive and mixed inhibitor of α-amylase and α-glucosidase respectively. Thereafter,the antiradical activity of synthesized vanadium(V)chalcone complexes was assessed with the help of DPPH radical scavenging assay. The results demonstrated that all the complexes were remarkable free radical scavengers for the DPPH. The complex 1 was observed to be best among them with the 0.03 µg/mL IC50 value. The AutoDockTools-1.5.6 software was used to examine structure-activity relationship and the binding interactions between oxovanadium(V) complexes and protein target alpha-amylase, alpha-glucosidase, and Myeloperoxidase respectively. The in-vitro as well as in-silico biological activity studies showed significant and major improvements after complexation of chalcone derivatives with vanadium oxychloride (VOCl3). Thus, oxovanadium(V)chalcone complexes were found to be potent inhibitors of the α-glucosidase and α-amylase enzyme.

Weakly bound complexes of selenophene with water as seen in matrix isolation FTIR

A spectroscopic and computational analysis of the selenophene:water complex is presented. The current study builds upon previous work completed on water complexes of other small heterocycles (furan and thiophene). Here, a computational analysis of the selenophene:water complex found seven unique geometries across multiple levels of theory and basis sets. Matrix isolation FTIR spectra were recorded for the complexes of selenophene with water and its isotopologues in nitrogen and argon. Analysis of these spectra allowed for identification of two structures; one that formed via a standard OH⋯π interaction and the other through a CH⋯O interaction. The full analysis of this data is presented along with a comparison to related complexes.

Third-order nonlinear optical studies of Bis(4-methylbenzylammonium) tetrachloridocuprate metal-organic crystal with optical limiting behavior: Experimental and theoretical investigations

The metal-organic nonlinear optical (NLO) compound Bis(4-methylbenzylammonium) tetrachloridocuprate (4MBA) was synthesized and grown by the slow evaporation method. X-ray crystal analysis revealed the crystal structure and conformation. Density functional theory (DFT) at B3PW91/LanL2DZ basis set level was applied and computed the optimized geometry, electronic structure, vibrational spectra, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), and natural bonding orbitals (NBO). UV–Vis-NIR spectroscopic measurements revealed the optical transparency range from 310 to 1100 nm and excited-state properties. The thermal behavior and stability of the compound were analyzed using TGA/DTA, and the suitability of the optical material is weighed. The dielectric parameters and AC conductivity were investigated as a function of frequency and temperature. Second-harmonic generation (SHG) efficiency was measured using the Kurtz and Perry powder approach and found 4MBA to be 0.8 times the KDP. The nonlinear refractive index (n2), nonlinear optical absorption (β) and third-order nonlinear optical susceptibility (χ(3)) measured values are 1.548 × 10−9 cm2 W−1, 0.0538 × 10−4 cm W−1, and 6.049 × 10−8 esu respectively, and shows that the 4MBA molecule is a third-order nonlinear optical material. The optical limiting threshold value is determined as 7.632 × 103 W cm2 for 532 nm continuous-wave laser, representing that the 4MBA is a strong candidate for the optical limiting application. The static and dynamic nonlinear optical parameters were computed with three different functions including B3PW91, M06 and PBE0 using LanL2DZ basis set. The outcomes revealed that the 4MBA molecule under study might be a promising NLO material for frequency generators and optical limiters applications.

Molecular structure, electronic properties, ESP map (polar aprotic and polar protic solvents), and topology investigations on 1-(tert‑Butoxycarbonyl)-3-piperidinecarboxylic acid- Anticancer therapeutic agent

The theoretical elucidation of 1-(tert‑Butoxycarbonyl)-3-piperidinecarboxylic acid (1TB3PC) was achieved in this work by using DFT/6–311++G(d,p) as the basis set level -B3LYP approach for the gas phase, polar aprotic, and protic solvents phases, respectively. Potential energy scan (PES) analysis and the optimized geometrical parameters for the gas, polar aprotic and polar protic solvent phases were attained and corresponding parameters were compared with the closely related molecule. The FMO's molecular orbitals (HOMO-LUMO) and the energy gap, FLU indices, and molecular electrostatic potential map (ESP) surface were carried out to predict the nucleophilic and electrophilic regions for the three phases (gas, polar aprotic, and polar protic solvents) were discussed. Further, the electron-hole distribution for the excited states and topological analyses (AIM, ELF, LOL and RDG) were also deliberated. To discern the biological activity of the title compound, drug likeness and ADMET predictions were carried out. Molecular docking approach was performed against ligand with various AKT /Protein Kinase B inhibitors targets and their corresponding parameters were conferred. Thus, the header composite designates as an alternative anticancer therapeutic agent.

Spectroscopic and Molecular Docking Studies of Cu(II), Ni(II), Co(II), and Mn(II) Complexes with Anticonvulsant Therapeutic Agent Gabapentin.

New Cu(II), Ni(II), Co(II), and Mn(II) complexes of the gabapentin (Gpn) bidentate drug ligand were synthesized and studied using elemental analyses, melting temperatures, molar conductivity, UV–Vis, magnetic measurements, FTIR, and surface morphology (scanning (SEM) and transmission (TEM) electron microscopes).The gabapentin ligand was shown to form monobasic metal:ligand (1:1) stoichiometry complexes with the metal ions Cu(II), Ni(II), Co(II), and Mn(II). Molar conductance measurements in dimethyl-sulfoxide solvent with a concentration of 10−3 M correlated to a non-electrolytic character for all of the produced complexes. A deformed octahedral environment was proposed for all metal complexes. Through the nitrogen atom of the –NH2 group and the oxygen atom of the carboxylate group, the Gpn drug chelated as a bidentate ligand toward the Mn2+, Co2+, Ni2+, and Cu2+ metal ions. This coordination behavior was validated by spectroscopic, magnetic, and electronic spectra using the formulas of the [M(Gpn)(H2O)3(Cl)]·nH2O complexes (where n = 2–6).Transmission electron microscopy was used to examine the nanostructure of the produced gabapentin complexes. Molecular docking was utilized to investigate the comparative interaction between the Gpn drug and its four metal [Cu(II), Ni(II), Co(II), and Mn(II)] complexes as ligands using serotonin (6BQH) and dopamine (6CM4) receptors. AutoDock Vina results were further refined through molecular dynamics simulation, and molecular processes for receptor–ligand interactions were also studied. The B3LYP level of theory and LanL2DZ basis set was used for DFT (density functional theory) studies. The optimized geometries, along with the MEP map and HOMO → LUMO of the metal complexes, were studied.

Bioactive Ni(II), Cu(II) and Zn(II) complexes with an N3 functionalized Schiff base ligand: Synthesis, structural elucidation, thermodynamic and DFT calculation studies

Some novel Ni(II), Cu(II) and Zn (II) metal complexes with new triaza Schiff base ligand (N-(2quinolylmethylidene)-4X-2-aminobenzene)imine (where X = Me, Cl, NO2)) have been synthesized. Various spectral techniques such as elemental analysis, magnetic susceptibility, conductivity, 1HNMR, IR, UV–Vis spectra, Mass spectrometry, powder XRD and EDX were used to confirm the structures. It has been found that the Schiff base behaves as a tridentate ligand forming chelates with 1:1 metal:ligand stoichiometry. The prepared Schiff base compounds were screened in vitro for their antibacterial activity against a number of pathogenic Gram positive and Gram negative bacteria, namely S.aureas and E.coli. The complexes show more potent activities than their free ligands. Spectrophotometric method and SQUAD program were applied to extract thermodynamic parameters to explain the complex formation behavior in solution at 25 °C in constant ionic strength (I = 0.1 M NaClO4). Also, density functional theory calculations at different level of DFT and basis set were employed to investigate optimized geometry, vibrational frequency analysis, electronic structure (energy of the HOMO and LUMO, Mulliken atomic charge, dipole moment, hardness and softness, electrophilicity and spectral properties) of the prepared Schiff base compounds. The DFT results showed that proposed structure and stability in ligands and their complexes are in accord with the experimental outcomes.

A DENSITY FUNCTIONAL THEORY (DFT) STUDY ON SILICON DOPED CARBON NANOTUBE Si-CNT AS A CARRIER FOR BMSF-BENZ DRUG USED FOR OSTEOPOROSIS DISEASE

This study aims to investigate the capability of Silicon-Doped Carbon Nanotube (Si-CNT) to detect and adsorb the BMSF-BENZ ((4-Bromo-7-methoxy-1-(2-methoxyethyl)-5-{[3-(methylsulfonyl)phenyl]methyl}-2-[4- (propane-2-))yl)phenyl]-1H-1,3-benzothiazole) molecular. For this purpose, we considered different configurations for adsorbing BMSF-BENZ drugs on the surface of the Si-CNT nanotube. All considered configurations are optimized using the density functional theory (DFT) at the 6-31G∗∗ basis set and B3LYP-B97D level of theory. Then from optimized structures, for each nanoparticle, we selected seven stable locations for the adsorption of BMSF-BENZ in (Br, N8, N9, N58, O35, O41 and S) active atoms on the surface of the selected nanoparticle. The quantum theory of atoms in molecules (QTAIM), reduced density gradient (RDG) analysis, and molecular orbital (MO) analysis were also established. The calculated results indicate that the distance between nanotube and drug from the N8 site is lower than from all other locations sites for all investigated complexes, and adsorption of BMSF-BENZ from the N8 site is more favorable for the Si-CNT nanotube. The adsorption energy, hardness, softness, and fermi energy results reveal that the interaction of BMSF-BENZ with Si-CNT is a promising adsorbent for this drug as Adsorption energy Eads of BMSF-BENZ/Si-CNT complexes are (-13.08, -43.50, -17.90, -31.29, -25.57, -16.56, and -28.05) kcal/mol in the gas phase. As well, the appropriate and spontaneous interaction between the BMSF-BENZ drug and Si-CNT nanoparticle was confirmed by investigating the quantum chemical molecular descriptors and solvation Gibbs free energies of all atoms.