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A computational study for reaction mechanism of 1-vinyl 5-hexenyl radicals is carried out using the density functional theory. The results showed that the reaction for the formation of thermodynamically stable 6-endo-trig cyclization product can progress over both 6-endo-trig and 5-exo-trig cyclization. Moreover, our computations demonstrated that when 5-exo-trig cyclization intermediate is stable, 5-exo-trig cyclization mode would be responsible for the formation of the 6-endo-trig cyclization product. [ABSTRACT FROM AUTHOR]

Due to its electronic properties, Zinc Oxide (ZnO) is one of the important materials used in new generation solar cells. However, it is necessary to increase the working efficiency of pure ZnO with the rays coming from the sun. Doping with foreign atoms is one of the important techniques in this sense. In this study, the doping of ZnO crystal with Se atom was investigated theoretically. Density functional theory (DFT) was used in the calculations. However, DFT+U correction was made in the calculations to correct the known errors of the theory. With this method, the band gap of pure ZnO was calculated at 3.27 eV. This value is close to the experimental value of 3.44 eV. The Se atom causes local distortions in the crystal structure. However, these deteriorations do not significantly change the characteristic properties of the ZnO crystal. Doping with Se mainly leads to a change in the electronic structure. When the Se and Zn atoms, which have more valence electrons, are replaced, two occupied energy levels are formed in the band gap, above the valence band maximum, due to impurity. These energy levels increase the light absorption activity of ZnO in the visible region. Another important data obtained is that the lack of oxygen in the Se-doped ZnO crystal positively affects the absorption activity in the visible region. [ABSTRACT FROM AUTHOR]

In this study, the magnetic nature and also, electronic characteristics of Ga4X3Mn (X=P and As) systems, which have simple cubic structure confirming P4 ̅3m space group and 215 space number, have been reported. All calculations realized within the framework of ab initio simulation methods have been performed using the meta-generalized gradient (META-GGA) approach within the Density Functional Theory (DFT). In view of the energy-volume curves and the calculated cohesive and formation energies for considering four different types of magnetic orders, it has been detected that these compounds have A-type antiferromagnetic nature. Also, the examined electronic behaviors in the A-type antiferromagnetic order of the related systems show that all two compounds are semiconductors due to having small band gaps in their electronic band structures (Eg = 0.23 eV for Ga4P3Mn and Eg = 0.16 eV for Ga4As3Mn).

This study reports the evaluation of 2-acetylpyridine based chalcone structure as a useful sensing material for Hg2+ ion detection by the means of UV-visible spectroscopy. In this context, firstly, the most common twenty metal ions were treated by the chalcone structure which was synthesized from 2-acetylpyridine and 4-diphenylaminobenzaldehyde according to the known procedures. As result, the studied chalcone compound exhibited good sensing activity towards Hg2+ ion in acetonitrile/water medium with significant red-shift phenomenon. In addition, some photophysical/electronic parameters of the chalcone and its Hg2+ complex were determined experimentally and theoretically. B3LYP, PBE0 methods and SVP, TVZP, and TVZPP basis sets were used for theoretical calculations in acetonitrile media. Finally, experimental results were explained and the proposed sensing mechanism was supported via density functional theory (DFT) outputs.

In this article, the structural and electronic properties of 2-(2-Bromo-5-Fluorophenyl)-7-Methoxy-3-Nitro-2H-Thiochromene were investigated theoretically using density functional theory. Molecular orbital analysis HOMO-LUMO was used to investigate the stability of the molecule. Intramolecular and intermolecular interactions in the crystal structure of the title compound were visualized by hirshfeld surface analysis and examined. Lipinski's rule of five showed that the 2-(2-Bromo-5-Fluorophenyl)-7-Methoxy-3-Nitro-2H-Thiochromene molecule is an orally active candidate and may be suitable for new drug design. In the last part of the study, the best binding pose of 4RJ3 PDB encoded protein to the ligand (the molecule under study) was determined by molecular docking method, and the binding energy and binding mechanism were examined. [ABSTRACT FROM AUTHOR]

In this study, 4-(5-methyl-[1,2,4]triazolo[1,5-a]pyrimidine-7-yloxy) phthalonitrile (coded as MTPPN) was chosen as the phthalonitrile compound and the quantum chemical and in-silico studies have been done. First, the basis set of the time dependent density functional theory (TD-DFT) method was used and the boundary orbital energies and band gap calculations of the molecule were performed. Analysis of atoms in molecules (AIM) theoretical calculations is presented to learn about electron density and bond critical point. In addition, absorption, distribution, metabolism, and excretion analyzes (ADME) were performed for the drug potential of the compound. On some enzymes effect of MTPPN compound was examined. The docking score was obtained for AChE, BChE, α-GLY proteins -7.864, -6.848, and -5.511 kcal/mol, respectively. MTPPN gave a good inhibitory performance in an in-silico study as a drug candidate. [ABSTRACT FROM AUTHOR]

In this study, the electronic behavior and mechanical properties of the ferromagnetic chalcospinel manganese-based selenide (AgMn2Se4) which crystallized in face centered cubic structure with space group Fd3 ̅m and space number 227, were investigated. All ab initio calculations were carried out by Generalized Gradient Approximation (GGA) under spin polarization. For this composition, three different type magnetic orders were considered to detect the most stable magnetic character. For the given composition, the results of the computations indicate its ferromagnetic nature since this compound has a lower ground state energy in this magnetic order than in other magnetic phases. After determining the most energetically stable magnetic phase, the electronic behavior in this magnetic arrangement was examined. The observed electronic band structure under spin polarization of this compound shows that this selenide system is almost half-metallic material due to having small band gap (Eg = 0.09 eV) in the minority spin state. In addition, the mechanical stability was determined with the help of elastic constants which were also employed to determine the mechanical characteristics of this compound.

Structural, magnetic, electronic and elastic properties of the ternary Ti2RuSn alloy in reverse- Heusler (XA) structure were investigated using density functional theory and generalized grandyent approach. It was seen that the calculated optimized lattice constant, total magnetic moment and electronic band structure were compatible with the available data in the literature. From the spin polarized band calculation, it was predicted that the Ti2RuSn alloy has a band gap of 0.405 eV in the spin-down orientation, while it shows metallic properties in the spin-up orientation and therefore has a semi-metallic ferromagnetic nature. The results of the second order elastic constants were found to meet the Born mechanical stability criteria for this alloy and to be mechanically stable. In addition, it was determined that this alloy, which has a B/G ratio of 3.23 according to Pugh criteria, has a ductile nature due to its greater than 1.75 limit and exhibits anisotropic behavior due to its anisotropy factor (A) of 2.88. It can be said that the investigated alloy is a promising candidate for spin electronics applications. [ABSTRACT FROM AUTHOR]

In this study, the 2-chloro-1-(6-flouro-3,4-dihydro-2H-chromen-2yl)ethanone molecule which was synthesized and whose structure was illuminated by X-ray diffraction method in previously study was determined by chemical activity, second order nonlinear optical properties and interactions with DNA bases were investigated. Density functional theory was chosen as the theoretical method because of it is significant values close to experimental and its computational cost. There is no imaginary frequencies was observed as a result of the frequency calculations also supported the optimized structure and thus other properties were obtained and interpreted from the optimized structure. The stable molecular geometry of the studied molecule was obtained by optimization. DFT/B3LYP/6-311++G(d,p) bases set was used in all theoretical calculations. It was seen that the geometric parameter values of the optimized molecule were compatible with the experimental data and thus other properties obtained through the optimized structure were calculated and interpreted. In the calculation of the chemical activity of the molecule, hardness, softness and other chemical activity parameters were obtained by frontier molecular orbital (HOMO, LUMO) energies. Molecular electrostatic potential (MEP), charge population and Fukui functional analaysis was determined in which regions the structure is susceptible to chemical interactions. Inaddition to these, molecular interactions, Hirshfeld surface maps, interaction percentages of atoms with each other (2D-finger print) were examined by Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

In this study, dibenzo[a,c]phenazine based acceptor was combined with donors and acceptor to obtain donor-π-acceptor type potential thermally activated delayed fluorescence (TADF) emitters. All molecules’ structural and electronic properties were computed theoretically at the level of Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TD-DFT) with the application of three different hybrid functionals. Most of the designed structures were found to have the potential to be TADF compounds. This is because it has a very narrow energy gap between the first excited single and triple states. As a result, the designed derivatives can be calculated as the best candidates for the purpose and also have very strong potential to serve as an efficient Organic Light (Emitting Diode) OLED material [ABSTRACT FROM AUTHOR]

In this work, the corrosion prevention behaviors of pyrimidine derivatives (1-12) were investigated by theoretical quantum chemical calculation. Quantum chemical parameters obtained by theoretical calculations such as the Highest Occupied Molecular Orbital (HOMO), Lowest Empty Molecular Orbital (LUMO), molecular electrostatic potential maps (MEP), electronegativity (χ), chemical potential (µ), global electrophilicity index (ω), chemical hardness (η) and global softness (σ) for all compounds were studied using density functional theory (DFT) at the B3LYP / 6-31G (d, p) level. Also, the fraction of transferred electrons (ΔN) between the iron surface and the pyrimidine derivatives compounds were calculated. However, nonlinear optical (NLO) properties have also been investigated. When the quantum chemical parameters obtained by theoretical calculations are examined, it has shown that compound 10 can be used as a good corrosion inhibitor with small ΔEgap (EHOMO-ELUMO), chemical hardness (η) values and high global electrophilicity index (ω), "ΔN" values. [ABSTRACT FROM AUTHOR]