Yusuf Atalay

Ab initio Hartree-Fock calculations on linear and second-order nonlinear optical properties of new acridine-benzothiazolylamine chromophores

The calculation of optimized molecular structure and molecular hyperpolarizability of four new acridine-benzothiazolylamine chromophores (1–4) [2-nitro-6-(piperid-1-yl) acridine (1), 6-(benzothiazol-2-yl-amino)-2-nitro-acridine (2), 6-(6-ethylcarboxylate-benzothiazol-2-yl-amino)-2-nitroacridine (3), 6-(6-(β-hydroxyethyl-benzothiazol-2-yl-amino)-2-nitroacridine (4)] have been investigated using ab initio methods. Ab initio optimization were performed at the Hartree–Fock level using STO-3G basis set. The first hyperpolarizabilities have been calculated at the Hartree–Fock method with 6–31G and 6–311G basis sets using Gaussian 98W. In general, the first hyperpolarizability is dependent on the choice of method and basis set. To understand this phenomenon in the context of molecular orbital picture, we examined the frontier molecular orbital energies of all the molecules by using HF/6–31G, 6–311G levels. The polarizability, anisotropy of polarizability and ground state dipole moment of all the molecules have also been calculated. These acridine-benzothiazolylamine chromophores display significant second–order molecular nonlinearity, β (60.2–137.0 × 10−30 esu) and provide the basis for future design of efficient nonlinear optical materials having the acridine-benzothiazolylamine core.

Theoretical investigation of 5-(2-acetoxyethyl)-6-methylpyrimidin-2,4-dione: conformational study, NBO and NLO analysis, molecular structure and NMR spectra.

Structural and conformational, natural bond orbital (NBO) and nonlinear optical (NLO) analysis was performed, and (1)H and (13)C NMR chemical shifts values of 5-(2-Acetoxyethyl)-6-methylpyrimidin-2,4-dione [C9H12N2O4] in the ground state were calculated by using Density Functional Theory (DFT-B3LYP/6-311++G(d,p)) and Hartree-Fock (HF/6-311++G(d,p)) methods. The NMR data were calculated by means of the GIAO, CSGT, and IGAIM methods. In addition, the molecular frontier orbital energies, thermodynamic parameters (in the range of 200-700 K), molecular surfaces, Mulliken charges and atomic polar tensor-based charges were investigated. Besides, the analysis of all possible conformational of the title compound, a detailed potential energy curve for τ1(C8O3C10O4), τ2 (C8O3C10C11) and τ3 (C5C7C8O3) dihedral angles were performed in steps of 10° from 0° to 360°, and depicted to find the most stable form. Finally, the calculated HOMO and LUMO energies show that charge transfer occurs within the title compound.

Molecular structure and vibrational and chemical shift assignments of 3-(2-hydroxyphenyl)-4-phenyl-1H-1,2,4-triazole-5-(4H)-thione by DFT and ab initio HF calculations.

The molecular geometry, vibrational frequencies, gauge including atomic orbital (GIAO) 1H and 13C chemical shift values and several thermodynamic parameters of 3-(2-Hydroxyphenyl)-4-phenyl-1H-1,2,4-triazole-5-(4H)-thione in the ground state have been calculated by using the Hartree-Fock (HF) and density functional methods (BLYP and B3LYP) with 6-31G(d) basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The molecule contains one O-H...N and one C-H...pi (phenyl) intramolecular interactions. The computed vibrational frequencies are used to determine the types of molecular motions associated with each of the experimental bands observed. Data of the title compound display significant structure-correlation and provide the basis for future design of efficient materials having the derivatives of 1,2,4-triazole. Also, calculated 1H chemical shift values compared with the experimental ones.

Quantum chemical characterization of N-(2-hydroxybenzylidene)acetohydrazide (HBAH): a detailed vibrational and NLO analysis.

The molecular modeling of N-(2-hydroxybenzylidene)acetohydrazide (HBAH) was carried out using B3LYP, CAMB3LYP and PBE1PBE levels of density functional theory (DFT). The molecular structure of HBAH was solved by means of IR, NMR and UV-vis spectroscopies. In order to find the stable conformers, conformational analysis was performed based on B3LYP level. A detailed vibrational analysis was made on the basis of potential energy distribution (PED). HOMO and LUMO energies were calculated, and the obtained energies displayed that charge transfer occurs in HBAH. NLO analysis indicated that HBAH can be used as an effective NLO material. NBO analysis also proved that charge transfer, conjugative interactions and intramolecular hydrogen bonding interactions occur through HBAH. Additionally, major contributions from molecular orbitals to the electronic transitions were investigated theoretically.

Molecular structure and vibrational and chemical shift assignments of 5-(2-Hydroxyphenyl)-4-(p-tolyl)-2,4-dihydro-1,2,4-triazole-3-thione by DFT and ab initio HF calculations

The molecular geometry, vibrational frequencies, gauge including atomic orbital (GIAO) 1H and 13C chemical shift values and several thermodynamic parameters of 5-(2-Hydroxyphenyl)-4-(p-tolyl)-2,4-dihydro-1,2,4-triazole-3-thione in the ground state have been calculated by using the Hartree-Fock (HF) and density functional method (DFT/B3LYP) with 6–31G(d), 6–31 + G(d,p) and LANL2DZ basis sets. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The computed vibrational frequencies are used to determine the types of molecular motions associated with each of the experimental bands observed. Also, calculated 1H chemical shift values compared with the experimental ones. The data of the title compound display significant molecular structure and IR, NMR analysis provide the basis for future design of efficient materials having the of 1,2,4-triazole core.

Molecular structure, vibrational spectra, NLO and NBO analysis of bis(8-oxy-1-methylquinolinium) hydroiodide

In this paper, quantum chemistry calculations of geometric parameters, harmonic vibrational wavenumbers, molecular frontier orbital energies (HOMO and LUMO) and the electronic properties of bis(8-oxy-1-methylquinolinium) hydroiodide ([(C(10)H(9)NO)(2)H(+)]·I(-)) have been performed by using Gaussian 09 program. The structural and spectroscopic data of the molecule in the ground state have been calculated by using Hartree-Fock (HF) and density functional method (DFT/B3LYP) with the LanL2DZ basis set. For the spectra predicted, a potential energy distribution (PED) is calculated. The (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts values of bis(8-oxy-1-methylquinolinium) hydroiodide molecule have been calculated by the gage including atomic orbital (GIAO) method. Furthermore, molecular electrostatic potential maps (MEP), Mulliken charges and the natural bonding orbital (NBO) analysis of the compound have been calculated by the HF and B3LYP/Lanl2DZ methods.

An experimental and theoretical study on the novel (Z)-1-((naphthalen-2-ylamino)methylene)naphthalen-2(1H)-one crystal

A novel compound has been synthesized, and its structure has been characterized by IR, UV-vis, NMR and X-ray single-crystal determination techniques. The title compound crystallizes in the orthorhombic space group P212121 with a=6.2120(4)Å, b=10.8242(7)Å, c=22.3857(15)Å and Z=4. The crystal structure has intramolecular N-H···O hydrogen bond and C-H···Cg interaction. These hydrogen bonds and interactions are effective in crystal packing. The optimum molecular geometry, conformational analysis, normal mode wavenumbers, infrared and Raman intensities, corresponding vibrational assignments, chemical shift assignments, and thermo-dynamical parameters have been investigated with the help of Density Functional Theory (DFT). Detailed vibrational assignments have been made on the basis of potential energy distribution (PED). In order to understand the electronic transitions of the compound, time dependent DFT (TD-DFT) calculations were performed in gas phase. Also, the dipole moment, linear polarizabilities, anisotropy and first hyperpolarizabilities values have been computed.

The synthesis, characterization and theoretical study on nicotinic acid [1-(2,3-dihydroxyphenyl)methylidene]hydrazide.

In this study, we reported a combined experimental and theoretical study on nicotinic acid [1-(2,3-dihydroxyphenyl)methylidene]hydrazide (C13H11N3O3) molecule. The title compound was prepared and characterized by 1H and 13C FT-NMR, FT-IR and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P2₁/c with a=6.2681(3) Å, b=16.5309(7) Å, c=12.4197(6) Å, α=90°, β=111.603(4)°, γ=90° and Z=4. In addition, the molecular geometry, vibrational frequencies, gauge including atomic orbital (GIAO), continuous set of gauge transformations (CSGT), individual gauges for atoms in molecules (IGAIM) 1H and 13C NMR chemical shift values, natural bond orbital (NBO), nonlinear optical (NLO) and HOMO-LUMO analyses, molecular electrostatic potentials (MEPs) and thermodynamic properties of the title compound in the ground state were investigated by using Hartree-Fock (HF) and density functional theory (DFT/B3LYP) methods with 6-311++G(d,p). Besides, the hardness and electronegativity parameters were obtained from HOMO and LUMO energies. Obtained results indicate that there is a good agreement between the experimental and theoretical data.

1-Pentamethylbenzyl-3-(n)buthylbenzimidazolesilver(I)bromide complex: synthesis, characterization and DFT calculations.

A novel NHC complex of silver(I) ion, 1-pentamethylbenzyl-3-(n)buthylbenzimidazolesilver(I)bromide, was prepared and fully characterized by single crystal X-ray structure determination. FT-IR, NMR and UV-vis spectroscopies were employed to investigate the electronic transition behaviors of the complex. Additionally, the molecular geometry, vibrational frequencies, gauge including atomic orbital (GIAO) (1)H and (13)C chemical shift and electronic transition values of silver(I) complex were calculated by using density functional theory levels (B3LYP and PBE1PBE) with LANL2DZ basis set. Also, the vibrational frequencies were supported on the basis of the potential energy distribution (PED) analysis calculated for PBE1PBE level. We were also investigated total static dipole moment (μ), the mean polarizability (〈α〉), the anisotropy of the polarizability (Δα), the mean first-order hyperpolarizability (〈β〉) of the title complex. Natural bond orbital (NBO) analysis was performed to determine the presence of hyperconjugative interactions, and charge distributions.

The Synthesis, Characterization, Crystal Structure and Photophysical Properties of a New Meso-BODIPY Substituted Phthalonitrile.

A new highly fluorescent difluoroboradipyrromethene (BODIPY) dye (4) bearing an phthalonitrile group at meso-position of the chromophoric core has been synthesized starting from 4-(4-meso-dipyrromethene-phenoxy)phthalonitrile (3) which was prepared by the oxidation of 4-(2-meso-dipyrromethane-phenoxy)phthalonitrile (2). The structural, electronic and photophysical properties of the prepared dye molecule were investigated. The final product exhibit noticeable spectroscopic properties which were examined by its absorption and fluorescence spectra. The original compounds prepared in the reaction pathway were characterized by the combination of FT-IR, 1H and 13C NMR, UV–vis and MS spectral data. It has been calculated; molecular structure, vibrational frequencies, 1H and 13C NMR chemical shifts and HOMO and LUMO energies of the title compound by using B3LYP method with 6-311++G(dp) basis set, as well. The final product (4) was obtained as single crystal which crystallized in the triclinic space group P-1 with a = 9.0490 (8) Å, b = 10.5555 (9) Å, c = 11.7650 (9) Å, α = 77.024 (6)°, β = 74.437 (6)°, γ = 65.211 (6)° and Z = 2. The crystal structure has intermolecular C—H···F weak hydrogen bonds. The singlet oxygen generation ability of the dye (4) was also investigated in different solvents to determine of using in photodynamic therapy (PDT).