LANL2DZ Basis Set Research Articles

Vibrational and computational study on the characterization of Ag-Threonine complex

The current manuscript is emphasized on the vibrational spectroscopic study of l-Threonine-TCA (LTh-TCA) complex and metal-based complexes such as (l-Threonine-TCA)Ag [(LTh-TCA)Ag] and (l-Threonine-TCA)Ag2 [(LTh-TCA)Ag2] investigated under the Raman, FTIR and UV–vis techniques. The most favourable binding sites of the mentioned complexes were predicted under the density functional theory (DFT) evaluated using the B3LYP method and LANL2DZ basis set. The quantum chemical parameters of the complexes calculated under the DFT method affirm the chemical reactivity, bioactive property and distribution of electrons within the atoms of the molecules. The electronic transition of the atoms are analysed using the UV–vis simulation method performed under the IEFPCM solvation model by employing methanol as solvent. The AIM analysis is carried out to understand the interaction types manifested by the mentioned complexes. The bioactivity score and drug-likeness properties of the complexes are also analysed. The theoretical and experimental vibrational wave numbers of L-Th-TCA complex and its metal-based complexes are compared with each other and are found in good agreement with each other. The potential binding regions of the mentioned compounds with 1QCY collagen receptor is evaluated using the molecular docking analysis.

Mechanistic aspect for the atom transfer radical polymerization of itaconimide monomers with methyl methacrylate: a computational study

Abstract Atom transfer radical polymerization (ATRP) is a versatile & famous technique for the synthesis of well defined molecular architectures. In ATRP, there is a dynamic equilibrium exists between active & dormant species. Therefore, ATRP progress through a sequence of activation & deactivation cycles, ending upon complete monomer consumption & termination reactions are minimized. This paper presents a systematic computational study on kinetics & thermodynamics associates in the ATRP of itaconimide monomers & methyl methacrylate (MMA). For this, the copolymerization system is modeled as a unimer, dimer & trimer of various itaconimides & MMA monomer. The density functional theory with B3LYP functional & 6–31 + G(d)/LanL2DZ basis sets is used in the prediction of geometries & energetics associated with the dissociation of terminal R–X bond present in the unimer, dimer & trimer. The relative equilibrium constant (K ATRP) for the ATRP activation/deactivation steps is calculated from the free energy values associated with dissociation of R–X bond. The relative K ATRP values of dimer & trimer of selected monomers is compared with their respective unimer. From the transition state geometries of the dimeric propagating radical, activation energy is calculated. The gas phase rate coefficients for propagation (k p) (of itaconimides & MMA copolymerization) are calculated using the standard transition state theory. The effect of system parameters such as solvent, temperature & substituent on K ATRP & k p values of dimer is investigated systematically. The change in the initiating system & temperature has significant effect on k p values as compared to solvent & various substituent. The K ATRP values of dimer & trimer dormant species are higher as compared to their respective monomeric species. The neighboring monomer & penultimate monomer plays vital role in kinetics & thermodynamics associated with copolymerization. The obtained initial results show that the mechanism of copolymerization of itaconimide monomers & MMA follows penultimate model.

A novel Schiff base ligand and its metal complexes: Synthesis, characterization, theoretical calculations, catalase-like and catecholase-like enzymatic activities

In this study, a new Schiff base (H2L), which has not been recorded in the literature, and its metal complexes with general formula [ML].(H2O) [M: Cu(II) and Mn(II)] were synthesized and their structures were elucidated. Techniques such as 1H- and 13C-NMR, FT-IR, UV–vis, TG-DTG, molar conductivity, magnetic susceptibility, ICP-OES, and elemental analysis were used to characterize the structures of the Schiff base and metal complexes. According to the analysis's findings, the complexes' metal:ligand ratio was 1:1. Additionally, the 6-311G(d,p) and LANL2DZ basis sets of the DFT/B3LYP method were used to calculate the optimized molecular geometries of the H2L and its metal complexes, respectively. Additionally, the synthesized compounds' molecular electrostatic potential (MEP) diagrams, frontier molecular orbitals (HOMO-LUMO), chemical shift values for the 1H- and 13C-NMR, vibrational frequencies, and wavelengths of electronic transitions were all determined. Experimentally obtained results were verified with theoretical data that matched well. [CuL].(H2O) and [MnL].(H2O) were examined for their catalase-like and catecholase-like enzymatic activities using volumetric and spectrophotometric techniques, respectively. For this objective, the catalytic activities of the synthesized molecules in the disproporsion reaction of H2O2 in the presence of 1-methylimidazole and the oxidation reaction of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylquinone in aerobic medium were investigated. According to the enzyme-like studies, [MnL].(H2O) was more catalytically active than [CuL].(H2O) in both of the mentioned reactions.

Theoretical Investigation on the Mechanistic Pathways of Cp*Cobalt(III)- Catalyzed Transformation of N-Substituted Carbamoyl Indoles to Pyrroloindolone Derivatives

Aim: A theoretical study on the Cp*cobalt(III) catalyzed C-H functionalization transformation of N-substituted carbamoyl indoles with alkyne derivatives to pyrroloindolone derivatives has been performed using DFT method. Background: Indole skeleton is an important part for developing regioselective C-H bond functionalisation reactions. Pyrrolo[1,2-a]indole bearing a 6-5-5 tricyclic skeleton (Scheme-1) is an important structural component found in many biologically active natural products and pharmaceuticals, (such as antitumor mitomycin C, antimalarial flinderole B etc.).Thus C−H activation process has great demand methods for efficiently synthesizing a pyrrolo[1,2-a]indole unit from readily available starting materials. One such attractive report was published by Matsunaga & Kanai et.al., Which shows pyrroloindolone derivatives can be synthesized (Scheme-2) through Cp*Co(III) catalysed C-H alkenylation and annulations from N-substituted carbamoyl indoles. Objective: Our current project deals with the determination of the rate determining step of the reaction, to determine the energetically favourable pathway. Investigation of the actual reason behind the regioselectivity of the products whether it is steric or electronic effects of the substituents. Method: The geometry optimization and energy calculations of all the systems were carried out with the Gaussian 09 software. Construction of trial geometries, monitoring the progress of calculations and visualization of the final output were done by several graphical user interface softwares like Gauss View, Molden etc. Geometry optimization of all species is performed using M06-2X functional in DFT method as a method for performing optimization of structures. 6-31G (d, p) basis set was employed for all non-metal atoms and the LANL2DZ basis set was employed for cobalt. To find out the geometries of several transition structures on the potential energy surface (PES) of the reaction pathway, relaxed scan method was used. Result: DFT study on a reaction of carbamoyl indoles with alkyne derivatives by activate Co(III)Cp* catalytic condition is done here. The target scheme followed the energetics of two possible pathways. The initial step of the reaction is the alkyne insertion step which needs 21.27 kcal mol-1 amount of energy. In the first case the final annulated product has been generated through a carbon-carbon bond formation, proton transfer and demetallation processes in path-a. The global activation barrier has been found to be quite high (30.17 kcal mol-1). However the study of the second pathway, which generated the simple alkenylated product through the proto-demetalation process in path-b, reveals a more reliable activation barrier (21.27 kcal mol-1). Conclusion: Comparison of the energy requirement clearly reveals that the formation of the final product should go through favourable simple alkenylation process that is path-b for dimethyl amine. Due to lower energy barrier the simple alkenylation pathway (i.e Path-b) is more favourable one. Initial alkyne addition step is the rate determining step. The regioselectivity of the alkyne addition is purely governed by the steric crowding around the substrate. Thus the favourable mode of alkyne addition has lower energy barrier due to lesser steric interactions. This theoretical investigation may guide the future researchers for developing some other economical route for generating similar derivatives.

Zinc(II) complex of (Z)-4-((4-nitrophenyl)amino)pent-3-en-2-one, a potential antimicrobial agent: synthesis, characterization, antimicrobial screening, DFT calculation and docking study

ABSTRACT. Herein, the synthesis and characterizations of (Z)-4-((4-nitrophenyl)amino)pent-3-en-2-one (HL) ligand and its Zn(II) complex are reported. The compounds were characterized using elemental and thermogravimetric (TGA) analysis, electrochemical studies, FTIR, UV-Vis, 1H and 13C{H}NMR, HRMS, and PXRD techniques. Antimicrobial activity was screened on some Gram-positive and Gram-negative bacteria. DFT predictions were achieved using B3LYP, ωB97XD and M06-2X functional with 6-31+G(d,p) and LANL2DZ basis sets for nonmetallic and metallic atoms, respectively. The therapeutic potentials of the compounds were evaluated based on protein binding affinity, ADME/T and drug-likeness properties. The experimental results revealed the formation of a complex in which two ligands coordinated to the zinc ion in a tetrahedral arrangement through their carbonyl and amino groups. The antimicrobial study showed that the complex possesses higher antimicrobial activity than free ligand and the control (Streptomycin). B3LYP emerged as the best performing functional having yielded the best IR spectra and geometrical parameters relative to the experimental data. The density functional theory (DFT) predictions revealed that the complex is more active than the ligand, and its formation is thermodynamically feasible and exothermic. The docking results revealed that the binding affinities of the compounds are in agreement with the in-vitro data, and they possess drug-like properties.
 
 KEY WORDS: Schiff base, Zinc complex, Antimicrobial, DFT, Docking study
 
 Bull. Chem. Soc. Ethiop. 2023, 37(3), 633-651. 
 DOI: https://dx.doi.org/10.4314/bcse.v37i3.8

Synthesis, Characterization, Crystal Structures, and Supramolecular Assembly of Copper Complexes Derived from Nitroterephthalic Acid along with Hirshfeld Surface Analysis and Quantum Chemical Studies.

Two new Cu(II) carboxylate complexes, Cu-NTA and Cu-DNTA, were prepared by treating 2-nitroterephthalic acid with CuSO4·5H2O at room temperature. The synthesized complexes were characterized by elemental (CHN), FT-IR, and thermogravimetric analysis. The crystal structures of both complexes were explored by single crystal X-ray diffraction analysis, which inferred that the coordination geometry is slightly distorted octahedral and square pyramidal in Cu-NTA and Cu-DNTA, respectively. The non-covalent interactions that are the main feature of the supramolecular assembly were investigated by Hirshfeld surface analysis for both complexes. The propensity of each pair of chemical moieties involved in crystal-packing interactions was determined by the enrichment ratio. Quantum chemical computations were performed to optimize the molecular geometry of complex Cu-NTA and compared it with the experimental single crystal structure, which was found to be in sensible agreement with the experimental structure of the complex. The DFT method was used to see the potential of the selected Cu-NTA complex for linear and nonlinear optical properties. The static NLO polarizability <γ> of complex Cu-NTA was calculated to be 86.28 × 10-36 esu at M06 functional and 6-31G*/LANL2DZ basis set, which was rationally large to look for NLO applications of complex Cu-NTA. Additionally, the molecular electrostatic potential and frontier molecular orbitals were also computed with the same methodology to see electronic characteristics and ground-state electronic charge distributions.

Synthesis, spectroscopic, and molecular interaction study of lead(II) complex of DL-alanine using experimental techniques and quantum chemical calculations

The current work focuses on the synthesis and spectroscopic studies of Pb(II) complex of DL-alanine using FTIR, Raman, UV–Vis, 1H N.M.R., and powder X-ray diffraction techniques. The theoretical analysis is performed by using DFT approach under B3LYP and M06-2X functional with LANL2DZ basis set. The MEP surface is mapped and the HOMO-LUMO gap is determined to reveal the reactivity parameters of the complex. The natural bond orbital analysis is carried out to study the charge delocalization and the stability of the complex. Wiberg bond indices and AIM analysis are performed to probe the nature of the metal-ligand interactions. Furthermore, RDG-NCI analysis based on electron density topology is employed to get more details about the non-covalent interaction happening in the metal complex. The shift in vibrational peaks of the complex is investigated in its free ligand. The attractive NLO application of the complex is illuminated through the first-order hyperpolarizability parameters. The theoretically and experimentally assigned wavenumbers of Pb(DL-alanine)2 complex are found in concurrence with each other. Finally, computational docking is utilized to study the plausible binding modes of Pb(DL-alanine)2 with divalent metal transporter 1 (PDB ID 5F0L) to shed light on the lead elimination mechanism mediated by DL-alanine in the lead detoxification process.

Synthesis, crystal structure, DFT studies and catalytic activity of an N-(2,2-dimethyl-1,3-dioxolane-4yl-methyl)benzimidazole ruthenium(II) hydrate complex

In this study, the new N-coordinated benzimidazole ruthenium(II) complex was synthesized. The complex was fully characterized by FT-IR, 1H and 13C NMR spectroscopic methods. The molecular structure of the complex has been verified by X-ray crystallography. Besides, theoretical structure and spectroscopic data were obtained using density functional theory (DFT/HSEH1PBE) method with the cc-pVDZ basis set for C, H, N, O and Cl atoms, and the LANL2DZ basis set for the metal atom, and compared with the experimental data. This complex has also been tested for the N-alkylation of aromatic amines with arylmethyl alcohols under neat conditions in the presence of KOBut.

Accomplishment the Geometrical and Finding the Electronic features for (3B5)Ag, (3B5)Cd, (3B5)Cr, (3B5)Cu, (3B5)Mo, (3B5)Nb, (3B5)Ni and (3B5)Zn by Utilizing The Quantum Computational method DFT at LanL2Dz and LanL2MB basis sets

Accomplishment the Geometrical and Finding the Electronic features for (3B5)Ag, (3B5)Cd, (3B5)Cr, (3B5)Cu, (3B5)Mo, (3B5)Nb, (3B5)Ni and (3B5)Zn by Utilizing The Quantum Computational method DFT at LanL2Dz and LanL2MB basis sets

Tris chelated meridional isomers of Co(III) complexes: Synthesis, crystal structure, protein binding, cytotoxicity studies and DFT/TDDFT calculation

Two mononuclear Co(III) complexes, [Co(L1)3] (1) and [Co(L2)3] (2) (HL1, 2-[(2-methoxy-ethylimino)-methyl]-phenol; HL2, 1-[(2-methoxy-ethylimino)-methyl]-naphthalen-2-ol) have been synthesized and characterized by X-ray crystal structure determination, IR and mass spectroscopic techniques. Both the complexes are mononuclear with distorted octahedral geometries and the Co(III) center are coordinated with three bidentate (O, N) Schiff base ligands. Complexes 1 and 2 form 1D and 3D supramolecular structures, respectively, with weak CH…π interactions. Experimental UV–vis absorption spectra have been compared with the results obtained from DFT / TD-DFT calculation using B3LYP functional and LanL2DZ basis set. The interaction of the complexes with bovine serum albumin (BSA) and human serum albumin (HSA) were studied using electronic absorption and fluorescence spectroscopic methods and the results show that complexes potentially quench the fluorescence of BSA/HSA through ground state association mechanism. Cytotoxicity studies of these complexes have been performed against breast cancer cell lines and found that they have moderate anticancer activity.

Experimental and DFT studies on the structural and optical properties of chitosan/polyvinyl pyrrolidone/ZnS nanocomposites

AbstractChitosan/Polyvinyl pyrrolidone (CS/PVP) semi-natural polymeric blend involving gradient concentrations of ZnS nanoparticles (ZnS-NPS) was prepared via a simple casting method. In conjunction with computational density functional theory approaches (DFT), prepared samples were characterized by UV/Vis spectrophotometric studies and Fourier transform infrared measurements (FTIR) to take into account a detailed description of the different reaction mechanisms within the polymeric matrices. To conduct all calculations, the Becke three-parameter hybrid functional (B3LYP) correlation function used with the electron core potential basis set LANL2DZ was used. A detailed study of different reaction regimes was studied and reaction via Oxygen was observed to be preferred and compatible with that of the experimental data. UV/vis. Absorption experimental data were used to calculate the optical energy gap using the Mott-Davis equation and observed data was found to follow an indirect transition route.

Mononuclear half-sandwich nd7 metallo drug complexes based on bidentate N∩N dendritic scaffolds: DFT (B3LYP; BP86 and B3PW91) examination

Through an use of three functionals (B3PW91, B3LYP and BP86) associated to a generic basis set LanL2DZ for transition metals (as well as halogen atoms) and 6-311+G (d,p) for others atoms, an examination of the bonding properties of a series of mononuclear half-sandwich nd7 transition metal (anticancer) complexes based on N∩N dendritic scaffolds (L) has been done. Collectively, complexes studied have adopted the piano-stool environment. An examination of the performance of each functional has shown that for the most reliable geometrical analysis of Metal-Nitrogen and Metal-Halogen bonds, the B3LYP and B3PW91 functionalities are suitable respectively. Regardless of the halogen ligand adopted, the B3LYP metal-nitrogen bond lengths are the most widely overestimated. A correlation has been built between the retained charge on each divalent transition metal cation and its metal ion affinity (MIA). Topological examinations reveal the higher instability of metal-N bonds compared to metal-X ones (X = Cl and Br). By the mean of the energy decomposition analysis, a predominant electrostatic character of metal … halogen and [LCP]- … [MX]+ interaction has been demonstrated. The transition metal atom … (hydrophobic) surface (Cp*) interaction is most pronounced for the chloride rhodium complexes of rhodium (combined with (E)-N-(pyridin-2-ylmethylene) Propan-1-amine and 2,2′- dipyridylketone ligands and iridium combined with 2,2′- dipyridylketone ligand. The charge decomposition analysis displays the weakening of the [MLCP*]+−X− bonds in the studied complexes.

Application of zinc oxide nano-tube as drug-delivery vehicles of anticancer drug

Zinc oxide nano-tube (ZnONT) nano-structures, which possess chemical stability and non-toxicity in the human body, are considered promising for delivering different drugs. Within this work, we scrutinized the drug delivery capability of the ZnONT and its adsorptional properties as a drug delivery vehicle (DDV) for hydroxyurea (HU) as an anti-cancer drug through density functional theory along with the solvent impacts. Based on the optimized structures, it can be suggested that Zn atoms of ZnONT are the ideal sites on this nano-tube for the adsorption of HU. HU had a strong physical adsorption through the O atom of carbonyl groups onto the local pyramidal site of the ZnONT. At 1.96 Å and Ead of -39.28 kcal/mol, in the configuration which was favorable in terms of energy, there was an interaction between the O atoms of -C=O group of the drug and a Zn atom of the ZnONT. In order to scrutinize the excited state properties of the HU-ZnONT complex, we also examined the UV/Vis data of the HU/ZnONT interaction system. Following the adsorption of HU onto the surface of the ZnONT, there was a significant red-shift based on the maximum absorption wavelength, showing that the ZnONT is an ideal candidate for optic sensors in order to detect and monitor the drug molecule. HU could be released in the cancer tissues where pH was low based on the drug release mechanism. The current work thoroughly investigated the mechanism of interaction between the ZnONT and HU, showing that ZnONT can be used for the smart drug delivery of HU. Overall, the findings suggest that ZnONT could be used as an efficient drug-delivery system for the HU drug to treat various types of cancer. In this work we used B3LYP-gCP-D3 functional and the basis set LANL2DZ on the transition metal (Zn) and the basis set cc-pVDZ on the others. GAMESS software program was employed for performing the calculations. we performed analyses, including charge transport, molecular electrostatic potential surface (MEP), energetic, electronic, natural bond orbitals (NBOs), and structural optimizations.

Interaction of a novel inorganic nickel complex with tyrosinase as potential inhibitor: Synthesis, spectroscopic, DFT, NBO, docking and ADMET properties

The obtained Ni(II) complex has been synthesized and characterized by elemental analysis (EA), spectroscopic studies such as FT-IR, UV-Vis. and MS. Also, thermal analysis (TG and DTG) analysis, X-ray powder diffractometry (PXRD) and morphological (SEM/EDXS) measurements were as well performed. By using cyclic voltammetry (CV), the redox properties of NiII(L)2 complex was found to be a quasi-reversible Ni(II)/Ni(I) redox system. The structure of NiII(L)2 complex was investigated by utilizing density functional theory (DFT) calculations with the Becke 3-Lee-Yang-Parr (B3LYP) method employing the LANL2DZ basis set. Frontier molecular orbitals (FMOs), important parameters of reactivity, Mulliken charge and Natural bond orbitals (NBOs) computational studies on NiII(L)2 complex were carried out in the ground state using DFT theory at B3LYP/ LANL2DZ level. This complex was found to exhibit, in vitro, a strong tyrosinase inhibitory activity with an IC50 value of 5.7 μM approximately 6.5-fold better than kojic acid as positive control IC50 = 37.86 µM). The binding energy of the best pose, in silico, is – 8.7 kcal/mol. Thus, these results showed a good agreement with the experimental data obtained from the enzyme-inhibiting assay.

Design, Synthesis, Spectroscopic Inspection, DFT and Molecular Docking Study of Metal Chelates Incorporating Azo Dye Ligand for Biological Evaluation.

A new heterocyclic azo dye ligand (L) was synthesized by the combination of 4-amino antipyrine with 4-aminophenol. The new Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) complexes were synthesized in excellent yields. The metal chelate structures were elucidated using elemental analyses, FT-IR, 1H-NMR, mass, magnetic moment, diffused reflectance spectral and thermal analysis (TG-DTG), and molar conductivity measurement. According to the FT-IR study, the azo dye ligand exhibited neutral tri-dentate behavior, binding to the metal ions with the azo N, carbonyl O, and protonated phenolic OH. The 1H-NMR spectral study of the Zn(II) complex supported the coordination of the zo dye ligand without proton displacement of the phenolic OH. Diffused reflectance and magnetic moment studies revealed the octahedral geometry of the complexes, as well as their good electrolytic nature, excepting the Zn(II) and Cd(II) complexes, which were nonelectrolytes, as deduced from the molar conductivity study. The theoretical calculations of optimized HOMO-LUMO energies, geometrical parameters, electronic spectra, natural atomic charges, 3D-plots of MEP, and vibrational wavenumbers were computed and elucidated using LANL2DZ and 6-311G (d, p) basis sets of density functional theory (DFT) with the approach of B3LYP DFT and TD-DFT methods. The ligand and complexes have been assayed for their antimicrobial activity and compared with the standard drugs. Most of the complexes have manifested excellent antimicrobial activity against various microbial strains. A molecular docking investigation was also performed, to acquire more information about the binding mode and energy of the ligand and its metal complexes to the Escherichia coli receptor using molecular docking. Altogether, the newly created ligand and complexes showed positive antibacterial effects and are worth future study.

Ligational behavior of bidentate nitrogen–oxygen donor 8‐quinolinolazodye toward Ni2+ and Zn2+ ions: Preparation, spectral, thermal, experimental, theoretical, and docking studies

The 5‐(4‐aryl azo)‐8‐hydroxyquinolines (L1–L3) and their metal complexes with Ni2+ and Zn2+ have been produced. Various spectroscopic techniques have been employed to analyze the ligand and complexes. The structures of the prepared compounds have been confirmed by Fourier transform infrared (FT‐IR), proton nuclear magnetic resonance (1H NMR), molar conductance, magnetic measurements, thermal gravimetric and differential thermal analyses (TG and DTA), and electronic transition. The FT‐IR spectra showed that the ligands are coordinated to the metal ions in a bidentate manner with donor sites of the azomethine‐N and phenolic‐OH. The FT‐IR and UV–Visible spectra were compared with the calculated results and showed a good agreement. The mass spectra concluded that the ligands' molecular weights and the calculated estimated m/z values match well. The complexes contain coordinated and hydrated water as confirmed by the TG results. The complexes are tetrahedral, trigonal bipyramid, and octahedral geometrical structures and act as non‐electrolytes in dimethylformamide (DMF) solvent. Using density functional theory (DFT) at the B3LYP level of theory and the 6‐311G** basis set for the C, H, N, Cl, and O atoms and the LANL2DZ basis set for the Ni and Zn atoms. Natural bond orbital (NBO) analysis was used to compute and describe the natural charge population and precise electronic configuration. The small energy gap between HOMO and LUMO energies suggests that charge transfer occurs within Ni2+ and Zn2+ complexes. The first‐order hyperpolarizability (β) of the complexes and the anisotropy of polarizability (α) values show promising optical properties. The electronic transitions of the prepared complexes were computed by time‐dependent density functional theory (TD‐DFT/PCM) with the B3LYP method using a 6‐31G** basis set. The ethanol polarizable continuum model (PCM) was used to simulate the solvent effect. Utilizing a computer virtual screening technique through molecular docking, the anticipation of binding of 8‐quinolinolazodye derivatives and their complexes with human CORONA virus protein (PDB ID: 5epw) was done.

Reduction Potential Predictions for Thirty-Seven 1,4-di-N-Oxide Quinoxaline-2-Carboxamide Derivatives with Anti-Tuberculosis Activity

The ability for density functional theory with the B3LYP functional with the lanl2dz basis set to predict the 1st (Wave 1) and 2nd (Wave 2) reductions of the diazine ring in a series of thirty-seven (37) 1,4-di-N-oxide quinoxaline-2-carboxamide derivatives in dimethylformamide was examined. The B3LYP/lanl2dz method had a strong correlation and low correlation to the experimental potentials for Wave 1 and Wave 2, respectively. There are nine identifiable analogs based on similarities of structure. The predicted reduction potentials for the derivatives of each analog generally fit the modified Hammett equation. The B3LYP/lanl2dz method is shown to be useful in accurately predicting the Wave 1 potentials for quinoxaline-di-N-oxide derivatives. For derivatives with assessable anti-tuberculosis activity, the predicted Wave 1 potentials have a similar correlation with the bioactivity when compared to the experimental wave 1 potentials.

Experimental and Theoretical Characterization of 3-(3,5-Dimethylbenzyl)-1-methyl-3,4,5,6-tetrahydropyrimidinium trichlorido(η6-p-cymene)ruthenate(II)

In this study, the title compound was synthesized, and its structure was illuminated by X-ray diffraction, 1H and 13C NMR spectroscopy methods. X-ray study shows that the crystal structure is stabilized by intermolecular C─H···Cl hydrogen bonds. Quantum mechanical approach was carried out to study the molecular structure, NMR spectra and stability of the compound by using Density Functional Theory (DFT) with HSEH1PBE functional and LanL2DZ basis set. Hirshfeld surface analysis was used as theoretical approach to assess driving force for crystal structure formation via the intermolecular interactions in the crystal lattice. In addition, chemical reactivity and kinetic stability of the molecule based on frontier molecular orbital analysis were investigated.

Adsorption of cytosine on Si and Ge doped graphene: A DFT study

This study describes how the cytosine adsorption on Si and Ge-doped Graphene uses density functional theory (DFT) calculations. The adsorption energies of cytosine on Si and Ge-doped Graphene are computed. The method used a hybrid B3LYP approach with 6-31G (d,p) and LANL2DZ basis sets to determine the Highest Occupied Molecular Orbital -Lowest Unoccupied Molecular Orbital HOMO and LUMO states and descriptors; and charge distribution potential. According to charge distributions, both Ge-doped and Si-doped graphene structures are sensitive to the cytosine base. The DNA base cytosine plays a crucial role as an adsorbent. When cytosine was adsorbed on Ge- and Si-doped graphene structures, the Highest Occupied Molecular Orbital -Lowest Unoccupied Molecular Orbital (HOMO-LUMO) gap decreased. This finding implies that the electrical conductivity of both systems has increased. The result shows that the Ge- and Si-doped graphene structures might be introduced as strong adsorbents for biosensor applications in various fields.

A Quinoline-Based Fluorescent Labelling for Zinc Detection and DFT Calculations

8-carboxamidoquinoline derivatives were gradually investigated as zinc's label in resolving weak water solubility, poor membrane permeability, and difficulty measuring free Zn2+ ion in cells quantitatively. The potential of 2-oxo-2-(quinolin-8-ylamino)acid (OQAA) as zinc's label was prepared and characterized spectroscopically. Theoretical and experimental data of OQAA were compared and discussed. The optimized molecular structure, molecular orbital of HOMO-LUMO, energy band gaps, and molecular electrostatic potential (MEP) of OQAA were carried out using the DFT method with Becke-3-Parameter-Lee-Yang-Parr (B3LYP) and 6-31G(d,p) basis set. The intermolecular interaction energy of OQAA-Zn is calculated by using the hybrid method of GEN with a basis set of LANL2DZ for Zn2+ ion and DFT/6-31G(d,p) for OQAA ligand. OQAA exhibited remarkable and excellent fluorescence enhancement selective and qualitatively only for Zn2+ than other metal cations tested (Fe2+, Cu2+, Co2+, Ni2+, Hg2+, Cd2+) under a long wavelength. Job's plot and 1H NMR titrations indicate OQAA-Zn2+ has a binding ratio at 1:1 stoichiometry (M1L1). Substantial shifting of amide N-H proton to higher chemical shift and intensity of the proton peak of N-H amide decrease abruptly implies that Zn2+ is binding to an amide. These changes confirmed interactions among the ligand OQAA and metal Zn2+ ion. As a result of the benefits discussed, OQAA could effectively and selectively optimize and fabricate for Zn2+ sensors.