4-Fenil-1, 3-Oksazolidin- 2-On ile kükürtlü analoglarının geometrik, optik ve titreşim özelliklerinin teorik olarak incelenmesi

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Bu çalışmada (R)/(rac)-4-fenil-1,3-oksazolidin-2-on ile bu molekülün diğer kükürtlü analoglarının kararlı durumdaki geometrik yapı parametreleri, infrared bölgesindeki titreşim frekansları ve optiksel sabitleri Hartree-Fock (HF) ve Becke-3-Lee-Yang-Parr (B3LYP) metotlarında sırasıyla 6-31G, 6-31++G, 6-31G(d,p) ve 6-31++G(d,p) temel setleri kullanılarak hesaplandı. Teorik olarak hesaplanan tüm değerler deneysel değerler ile karşılaştırıldı. Özellikle B3LYP metodu sonuçlarının HF metodu sonuçlarına göre deneysel değerlerle daha uyumlu olduğu gözlendi. Literatürde (R)/(rac) moleküllerin geometrik yapıları, titreşim frekansları ve özellikle infrared bölgesindeki optiksel sabitlerle ilgili teorik çalışmalar çok az olduğundan bu çalışma daha önem kazanmaktadır. Bununla birlikte teorik hesaplamalarda başlangıç geometrik yapı parametrelerinin sonuçlar üzerindeki etkisi ilk kez incelendi. Elde edilen sonuçların giriş değerlerine göre farklılık gösterdiği ortaya çıkarıldı.In this work geometrical structure parameters, vibration frequencies in the infrared region and optical constants of (R)/(rac)-1,3-oxazolidin-2-one and its Sulfur analogies have been calculated with Hartree-Fock (HF) ve Becke-3-Lee-Yang-Parr (B3LYP) methods with 6-31G, 6-31++G, 6-31G(d,p) and 6-31++G(d,p) basis sets respectively. All the theoretical results are compared with the experimental results. In particular, the results of the B3LYP method have been observed to fit better with the experimental values than HF method. In the literature, there are several studies on calculation of the (R)/(rac) molecular geometrical structures, vibrational frequencies and especially optical constants in infrared region. Therefore this work is important in this sense. The effect of initial geometrical structure parameters on the results of theoretical calculations has been investigated for the first time and it has been shown that the results varied with the initial values

4-Aminomorfolin molekülünün titreşim frekanslarının incelenmesi

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.ÖZET Anahtar kelimeler: Titreşim spektroskopisi, kırmızı-ötesi spektroskopisi, FTIR spektrometresi, grup teori, ligand, 4-aminomorfolin. Bu çalışmada 4-Aminomorfolin (C4H10N2O) molekülünün kırmızı-ötesi titreşim frekansları deneysel yolla ve teorik yolla Gaussian-98 programı ile beraber incelendi. Her iki sonucun uyumlu olduğu gözlendi. Ayrıca 4-aminomorfolin ligand olarak kullanılmasıyla ilk kez ML2NKCN4) (M= Cu ) kompleksi ele edildi ve titreşim frekansları deneysel olarak incelendi. Ligand frekansları kompleks oluşumu nedeniyle serbest durumundaki değerlerinden daha yüksek frekanslara kayma gözlendi. Bu kaymaların metal elementine bağlı olarak değiştiği ve ligandın iç titreşimleri ile M-N(Ligand) bağı titreşimleri arasındaki mekanik çiftlenim nedeniyle ortaya çıktığı saptanmıştır. vııExamination of the Vibrational Frequencies of 4-Aminomorfolin Molecule Key words: Vibrational spectroscpy, infrared spectroscpy, FTIR spectrometer, group theory, ligand, 4-aminomorpholine In this study infrared vibrational frequencies of 4-Aminomorpholine (C4H10N2O) molecules was studied experimentally and compared with theorical Gaussian-98 programme. It was seen that experimental results are good agreement with theorical results. However, by using 4-aminomorpholine as a ligand, MLaNi(CN)4 (M=Cu) complex was obtained for the first time. Ligand frequencies shifts to higher values with compared to frequencies free state. It has been realized that frequency shift reasons from mechanical coupling between the ligands internal vibrations and M-N(Ligand) bound vibrations. vi

Effect of Se content on the structural, morphological and optical properties of Bi2Te3-ySey thin films electrodeposited by under potential deposition technique

Bi2Te3-ySey thin films with different Se contents ranging from 0.3 to 2.5 were successfully electrodeposited by under potential deposition (UPD) technique onto gold foil substrates from an electrolyte consist of Bi(NO3)(3), TeO2, and SeO2 at ambient conditions. The effects of Se content on structural, morphological and optical properties of the products were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and FT-IR spectroscopy, respectively. The XRD analysis revealed that the diffraction peaks positions of Bi2Te3-ySey thin films shifts gradually towards the higher angle side due to replacement of Te by Se atoms in the crystal structure with increasing Se content. The SEM results showed that the particle size of Bi2Te3-ySe(y) thin films decreased as the Se content increased. The optical constants of ternary Bi2Te3-ySey thin films such as refractive index, extinction coefficient, and dielectric constant were obtained from the transmission spectra in the range of 2500-10.000 nm. The direct allowed band gap energies were estimated using Tauc equation and found to increase from 0.210 to 0.282 eV with increasing Se content from 0.3 to 2.5. The dispersion behavior of refractive index was studied by the single oscillator Wemple-DiDomenico model. (C) 2016 Elsevier Ltd. All rights reserved

Theoretical studies of molecular structure and vibrational spectra of 2-amino-5-phenyl-1,3,4-thiadiazole

The molecular geometry and vibrational frequencies of 2-amino-5-phenyl-1,3,4-thiadiazole (C8H7N3S) in the ground state has been calculated using the Hartree-Fock and density functional method (B3LYP) with 6-31G(d) basis set. The optimized geometric bond lengths and bond angles obtained by using HF and DFT (B3LYP) show the best agreement with the experimental data. Comparison of the observed fundamental vibrational frequencies of 2-amino-5-phenyl-1,3,4-thiadiazole (C8H7N3S) and calculated results by density functional B3LYP and Hartree-Fock methods indicate that B3LYP is superior to the scaled Hartree-Fock approach for molecular vibrational problems. (c) 2005 Elsevier B.V. All rights reserved

Molecular structure, IR and NMR spectra of 2,6 distyrylpyridine by density functional theory and ab initio Hartree-Fock calculations

Vibrational frequencies and gauge including atomic orbital (GIAO) C-13 NMR and H-1 NMR chemical shift values of 2,6 distyrylpyridine (C21H17N) in the ground state have been calculated by using the Hartree-Fock (HF) and density functional method (B3LYP) with 6-31G(d) basis set. These methods are proposed as a tool to be applied in the structural characterization of 2,6 distyrylpyfidine (C21H17N). The title compound has C-2 nu point group, thus providing useful support in the interpretation of experimental IR data. In addition, obtained results were related to the linear correlation plot of experimental C-13 NMR, H-1 NMR chemical shifts values and IR data. (C) 2007 Elsevier B.V. All rights reserved

Ab initio HF and DFT calculations on an organic non-linear optical material

The molecular geometric optimization, vibrational frequencies, and gauge-including atomic orbital (GIAO) (1)H and (13)C chemical shift values of 3-[(1E)-N-ethylethanimidoyl]-4-hydroxy-6-methyl-2H-pyran-2-one have been investigated by using ab initio Hartree-Fock (HF) and density functional method (B3LYP: Becke-3-Lee-Yang-Parr) with 6-31G(d) and 6-31++G(d,p) basis sets. Also, the first hyperpolarizabilities have been calculated at the HF and B3LYP levels employing the corresponding basis sets. To understand this phenomenon in the context of molecular orbital picture, we examined the molecular HOMOs and molecular LUMOs generated via HF and B3LYP levels. The computed vibrational frequencies are used to determine the types of molecular motions associated with each of the experimental bands observed. Data of 3-[(1E)-N-ethylethanimidoyl]-4-hydroxy-6-methyl-2H-pyran-2-one display significant second-order molecular nonlinearity and provide the basis for design of efficient nonlinear optical materials

Effects of Different Basis Sets and Donor-Acceptor Groups on Linear and Second-Order Nonlinear Optical Properties and Molecular Frontier Orbital Energies

The calculation of molecular hyperpolarizability, molecular frontier orbital energies of some donor-acceptor oxadiazoles (5a-f, 8a-f, and 9a-f) have been investigated using ab initio methods and different basis sets. Ab initio optimizations were performed at the Hartree-Fock (HF) and density functional (Beckee-3-Lee-Yang-Parr; B3LYP) levels of theory with 6-31G basis set. The polarizability (), anisotropy of polarizability (Delta alpha), and ground-state dipole moment (mu), first hyperpolarizability (beta), and molecular frontier orbital (HOMO, highest occupied molecular orbital and LUMO, lowest unoccupied molecular orbital) energies of 5a-f, 8a-f, and 9a-f have been calculated at the HF and B3LYP methods with 6-31G, 6-31G(d), 6-31+G(d), 631++G(d,p), 6-311G, 6-311G(d), 6-311+G(d), and 6-311++G(d,p) basis sets. Also, the molecular hardness (eta) and electronegativity (chi) parameters have been obtained using molecular frontier orbital energies. The , Delta alpha, mu, beta, HOMO, LUMO energies, eta and chi parameters have been investigated as dependence on the choice of method and basis set. The variation graphics of , Delta alpha, mu, beta, eta, and chi parameters using HF and B3LYP methods with different basis sets are presented. We have examined the frontier molecular orbital pictures of 5a-f, 8a-f, and 9a-f using B3LYP/6-31++G(d,p) level. The 5a-f, 8a-f, and 9a-f display significant linear, second-order molecular nonlinearity, and molecular parameters and provide the basis for future design of efficient nonlinear optical materials having the 1,3,4-oxadiazole core. (C) 2009 Wiley Periodicals, Inc. Int J Quantum Chem 111: 130-147, 2011https://doi.org/10.1002/qua.2241

Linear and non-linear optical properties of some donor-acceptor oxadiazoles by ab initio Hartree-Fock calculations

The molecular hyperpolarizability of some donor-acceptor oxadiazoles was investigated using ab initio methods. Ab initio optimizations were performed at the Hartree-Fock level using different basis sets, starting with the minimal basis set, and then split valence sets. The first hyperpolarizabilities were calculated at the Hartree-Fock level employing the corresponding basis sets using Gaussian 98W. In general, the first hyperpolarizability is dependent on the choice of method and basis set. In order to understand this phenomenon in the context of molecular orbital picture, we examined the molecular HOMOs and molecular LUMOs generated via HF/6-31G level. It has also been calculated the polarizability, anisotropy of polarizability and ground state dipole moment of all the molecules. Several of these oxadiazoles display significant second-order molecular nonlinearity, beta(8.57-195.05 x 10(-30) esu) and provide the basis for future design of efficient nonlinear optical materials having the oxadiazole core

Theoretical studies of molecular structure and vibrational spectra of glutaconic acid

The molecular geometry and vibrational frequencies of glutaonic acid (C5O4H6) in the ground state has been calculated using the Hartree-Fock (HF) and density functional method (B3LYP) with 6-31G(d) basis set. The optimized geometric bond lengths and bond angles obtained by using HF and DFT (B3LYP) show the best agreement with the experimental data. Comparison of the observed fundamental vibrational frequencies of glutaconic acid and calculated results by density functional B3LYP and Hartree-Fock methods indicate that B3LYP is superior to the scaled Hartree-Fock approach for molecular vibrational problems. (c) 2005 Elsevier B.V. All rights reserved

A theoretical study on 1-(thiophen-2-yl-methyl)-2-(thiophen-2-yl)-1H-benzimidazole

The molecular geometry and vibrational frequencies of 1-(thiophen-2-yl-methyl)-2-(thiophen-2-yl)-1H-benzimidazole (C16H12N2S2) in the ground state has been calculated using the Hartree-Fock (HF) and density functional method (B3LYP) with 6-31G(d) basis set. The optimized geometric bond lengths and bond angles obtained by using HF and DFT (B3LYP) show the best agreement with the experimental data. Comparison of the observed fundamental vibrational frequencies of 1-(thiophen-2-yl-methyl)-2-(thiophen-2-yl)-1H-benzimidazole (C16H12N2S2) and calculated results by density functional B3LYP and Hartree-Fock methods indicate that B3LYP is superior to the scaled Hartree-Fock approach for molecular vibrational problems. (C) 2006 Elsevier B.V. All rights reserved