Semiempirical and Density Functional Thoery Study on Structure of Fluoromethylfuran Oligomers

Abstract: Structural and electronic properties of oligomers of fluoromethylfurans (FMFs), OC 4 H 4 -CH n F 3-n with n = 1, 2, 3 and 4 have been studied using ZINDO/AM1 and B3LYP/6-31G(d) basis set. Preliminary study using AM1 and ab initio (HF) 6-31G(d) with medium basis set was carried out on di-, tri-and tetramer FMFs in order to investigate the stability of configuration of the polymer chains and conformation analysis of the dimers. There is noticeable effect of substituents on the geometries of FMFs as compared to polyfuran, polymethylfuran and chloromethylfuran (CMF) analogues [11]. The modeled FMFs have improved characteristics as conducting polymers compared to polyfurans, polymethylfurans and CMFs. The most stable conformation is the anti-planar conformation except in fluoromethylfuran in which anti-gauche conformation is most stable. The energy band gaps, electronic spectroscopy and electronic dipole moment vectors of the compounds are presented. Generally FMFs presented lower energy band gaps, longer wavelength and higher electric dipole moments and are therefore more suitable as monomer for conducting polymer especially trifluoromethylfuran

Theoretical Study on Structure and Electronic Properties of 4H-Cyclopenta[2,1-b,3;4-b’]dithiopene S-oxide and Its CCl₂ and CF₂ Bridged Derivatives

Quantum chemical calculations using semi-empirical, ab initio, density functional theory (DFT) and Møller plesset (MP2) methods were performed on 4H-Cyclopenta[2,1-b,3;4-b’]dithiopene S-oxide derivatives (i.e. bridged dithiophene S-oxides, BTOs). The geometries, stabilities, electronic and thermodynamic properties of the compounds were studied. The thermodynamic parameters calculated at PM3 were in good agreement with those calculated at B3LYP/6-31G(d) level. The band gap energies calculated at B3LYP/6-31G(d) level for the BTOs were lower than the un-substituted trithiophene but higher than 4H-Cyclopenta[2,1-b,3;4-b’]dithiopene. The absorption λmax calculated using TD-DFT was shifted to longer wavelength by successive replacement of methylene hydrogens of BTO by chlorine and fluorine atoms

DFT study on low molecular weight α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene and α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene S-oxide bridged derivatives

The equilibrium geometries of α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene (DBDT) and α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene S-oxide (DBDTO) were studied at the DFT level of theory with a standard 6-311G* basis set. The molecular structures of the DBDT series were more planar than the corresponding DBDTO series, as revealed by dihedral angles. The UV-visible absorption calculated at TD-DFT/6-311G* showed two absorption peaks for all the molecules except C=S and C=O bridged molecules. In DBDTOs, C=S and C=O bridged molecules showed three and four absorption peaks, respectively. The DBDTOs had lower band gaps and longer wavelengths compared to the corresponding DBDTs

DFT and QSAR study of corrosion inhibition on 3,5-di-substituted pyrazole derivatives with heteroatom on position one

Abdulazeez, M.O., Oyabamiji, A.K. and Semire, B. 2016. DFT and QSAR study of corrosion inhibition on 3,5-di-substituted pyrazole derivatives with heteroatom on position one. Lebanese Science Journal, 17(2): 217-232. A class of organic corrosion inhibitors namely; 2,5-bis(4-dimethylaminophenyl)-1,3,4-thiadiazole (DAPT), 2,5-bis(4-dimethylaminophenyl)-1,3,4-oxadiazole (DAPO), 3,5-diphenyl-4H-1,2,4-triazole (DHT), 3,5-di(4-pyridyl)-4H-1,2,4-triazole (PHT), 2,5-bis(4-aminophenyl)-1,3,4-oxadiazole (PAOX), 3,5-di(4-methylthiophenyl)-4H-1,2,4-triazole (4-MTHT) were investigated at density functional theory (DFT) B3LYP/6-31G** (d,p) level. The calculated molecular descriptors such as the HOMO, LUMO, the dipole moment, chemical potential (μ), chemical hardness (ղ), softness (s), global nucleophilicity (N) and average Mulliken charges on nitrogen atoms are discussed in relation to the observed inhibitory efficiency for the compounds. The developed qualitative structural activity relationship (QSAR) models relate the calculated molecular descriptors to the corrosion efficiency; thus QSAR model predicted the experimental corrosion efficiencies. The possible sites for nucleophilic and electrophilic attacks on the compounds were analyzed through the Fukui functions

Theoretical Examination of Efficiency of Anthocyanidins as Sensitizers in Dye-Sensitized Solar Cells

After experimental studies on the application of anthocyanidins as sensitizers in dye-sensitized solar cells (DSSCs) we have used computational methods to further elucidate the data obtained in the experimental study. In this study structural effects and electronic contributions of four anthocyanidins, cyanidin (Cy), delphinidin (Dp), malvidin (Mv) and pelargonidin (Pg), to improve the efficiency of DSSCs were investigated, using quantum chemical method, the density functional theory (DFT), to calculate parameters such as frontier molecular orbitals, band gap energies, reactivity descriptors.<br /

Biological Activity of Selected Compounds from Annona muricata Seed as Antibreast Cancer Agents: Theoretical Study

Several natural products have been of help to humans, and its effect is noticeable in the medicinal world. Soursop with botanical name Annona muricata L. possesses antidiarrhea, anticold fever, antirheumatism, and antineuralgia properties. In this work, five selected molecular compounds were studied against type 3 of 3α-hydroxysteroid dehydrogenase (3α-HSD). Its anticancer activity was investigated using the quantum chemical method via Spartan 14 software, molecular docking via Discovery studio 2017, AutoDock Tool 1.5.6, AutoDock Vina 1.1.2, and PyMol 1.7.4.4 and the molecular dynamic simulation method via AMBER14 molecular dynamics package. Many descriptors (EHOMO, ELUMO, dipole moment, energy bandgap, area, volume, polarizability, polar surface area, Log P, hydrogen bond donor, and hydrogen bond acceptor) which describe the anticancer activity of the studied compounds were obtained. Also, the docking study revealed the inhibiting ability of the studied compound, and it was observed that compound C possesses a greater ability to inhibit than other studied compounds as well as the standard (5FU)