Yazar "Ungordu, Ayhan" seçeneğine göre listele
Listeleniyor 1 - 15 / 15
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Antioxidant properties of methanolic extract of 'Veronica multifida' and DFT and HF analyses of its the major flavonoid component(Elsevier, 2019) Koc, Emre; Ungordu, Ayhan; Candan, FerdaThe experimental part of this study, investigated the effects of a methanolic extract of Veronica multifida on total phenolic and flavonoid content, antioxidant capacities; and DPPH scavenging activity. The methanol extract of V. multifida showed an equivalent of phenolic content of 196.67 mg gallic acid per gram dry weight, flavonoid content of 206.17 mg quercetin per gram dry weight and total antioxidant capacities of 134.41 mM alpha-tocopherol acetate per gram dry weight. Additionally, the amount of extract supplying 50% inhibition of DPPH was assayed as 66.65 mg L-1. The V. multifida plant extract to be used in the study was reported to contain luteolin as its main flavonoid component. The luteolin content of 0.2-0.5 mu g g(-1) was reported to be within the normal concentration range. Additionally, the antioxidant properties of luteolin were theoretically examined and compared to butylated hydroxytoluene and curcumin, which are respectively synthetic and natural antioxidants. The density functional theory (DFT) and Hartree-Fock methods were used in all calculations. The most stable structures of molecules were determined by using the B3LYP functional with the 6-311G(d,p) basis set. The theoretical methods showed that the antioxidant properties of pure luteolin are similar to those of butylated hydroxytoluene. (C) 2019 Elsevier B.V. All rights reserved.Öğe Charge transfer properties of Gaq3 and its derivatives: An OLED study(Elsevier, 2019) Ungordu, AyhanTris(8-hydroxyquinoline) gallium (Gaq3) is an alternative compound to tris(8-hydroxyquinoline) aluminum (Alq3) which is an organic light emitting diode (OLED) material. The performance of Gaq3 incorporated into OLEDs has been seen to be superior compared to that of Alq3-based ones but the OLED properties of a substituted Gaq3 complex has been not studied yet. For this reason, the OLED performances of Gaq3 and its derivatives were investigated theoretically. Gaq3, functionalized Gaq3 derivatives and their dimers were designed. While monomer calculations were performed on the B3LYP/6-31G(d) level, dimer computations were carried out on the B3LYP/TZP level. The reorganization energies (lambda e and lambda h), ionization potentials and electron affinities (adiabatic and vertical), energy gaps, effective transfer integrals (Je and Jh) and charge transfer rates (Ke and Kh) of the aforementioned molecules were calculated. Based on these parameters, the OLED behaviors of the compounds were estimated.Öğe DFT study on metal-mediated uracil base pair complexes(ELSEVIER SCIENCE BV, 2017) Ungordu, Ayhan; Tezer, NurtenThe most stable of metal-mediated uracil base pair complexes were determined. Method was used density functional theory, B3LYP. The calculations of systems containing C, H, N, O were described by 6-311++G(d,p) and cc-PVTZ basis sets and LANL2DZ and SDD basis sets was used for transition metals. Then Egap values of complexes were calculated and the electrical conductivity of the complexes for single nanowires was studied by band theory. Metal-mediated uracil base pair complexes which will be used as conductive wires in nanotechnology were predicted. In nanoworld, this study is expected to show a way for practical applications. (C) 2017 King Saud University. Production and hosting by Elsevier B.V.Öğe Effect on frontier molecular orbitals of substituents in 5-position of uracil base pairs in vacuum and water(WORLD SCIENTIFIC PUBL CO PTE LTD, 2017) Ungordu, Ayhan; Tezer, NurtenThe most stable structure of 5-substituted uracil base pairs and metal-mediated-5-substituted uracil complexes are determined. Density functional theory (DFT) method is used in the calculations which are carried out both in vacuum and water. LANL2DZ and 6311++G(d,p) basis sets are used for metals and the rest atoms, respectively. Effects on frontier molecular orbitals and energy gaps of substituents in 5-position of uracil base pairs in vacuum and water are found. Conductivity of base pairs or complexes are investigated for single nanowires studied by band theory. It is expected that this study will be an example for future studies that require new nanotechnological applications.Öğe Electronic Properties of Artificial Metal-DNA Base Pair Complexes Formed from Hydroxypyridone Base(Wiley-V C H Verlag Gmbh, 2020) Ungordu, Ayhan; Tezer, NurtenThe metal-mediated hydroxypyridone base pairs containing Ni2+, Cu2+, Zn2+, Pd2+, Cd2+, Pt2+, and Hg(2+)ions were designed theoretically using by density functional theory (DFT) method in Gaussian 09 program. The calculations which were performed in the gas phase, methanol, water, and formamide were done at B3LYP functional with LANL2DZ and 6-311++G (d, p) basis sets which were used metals and rest atoms, respectively. The Gibbs free energies of the complexes were calculated and their relative stabilities were determined in the mentioned fields. Furthermore, geometric parameters, HOMO, LUMO, energy gap energies of the compounds were computed in all media and effect on these parameters of solvents were determined. Based on these parameters, the relative conductivities of the investigated molecules were predicted. On the other hand, using Atomistix ToolKit (ATK-VNL) 2016 program, nonequilibrium Green's function (NEGF) calculations based on the combination DFT of the mentioned complexes were carried out. The transport properties of the molecules were found in detailed via NEGF-DFT method.Öğe Electronic, optical, and charge transfer properties of porphyrin and metallated porphyrins in different media(Wiley, 2020) Ungordu, AyhanPorphyrin and M-Porphyrin (M = Fe2+, Co2+, Ni2+, Cu2+, and Zn2+) complexes were designed to examine their organic light-emitting diode (OLED) properties. All calculations were performed in different media, which are gas, benzene, DMSO, and water phases. The calculations of both porphyrin and its metal complexes as a monomer form were performed at B3LYP/6-31G(d) level by using the Gaussian 16 and GaussView 6 package programs. On the other hand, emission calculations for the monomer form and dimer form computations of the studied compounds were carried out at PBE0/TZP and B3LYP/TZP levels, respectively, by using Amsterdam density functional (ADF) 2019 package program. The OLED tensors of the mentioned molecules, which are emission energies, reorganization energies (lambda(e) and lambda(h)), the ionization potentials and the electron affinities (adiabatic and vertical), the effective transfer integrals (V-e and V-h), and the charge transfer rates (W-e and W-h), were calculated to evaluate the OLED behaviors and determine the best OLED structure.Öğe Investigation of anticancer properties of caffeinated complexes via computational chemistry methods(PERGAMON-ELSEVIER SCIENCE LTD, 2018) Sayin, Koray; Ungordu, AyhanComputational investigations were performed for 1,3,7-trimethylpurine-2,6-dione, 3,7-dimethylpurine-2,6-dione, their Ru(II) and Os(III) complexes. B3LYP/6-311 ++G(d,p)(LANL2DZ) level was used in numerical calculations. Geometric parameters, IR spectrum, H-1-,C-13 and N-15 NMR spectrum were examined in detail. Additionally, contour diagram of frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP) maps, MEP contour and some quantum chemical descriptors were used in the determination of reactivity rankings and active sites. The electron density on the surface was similar to each other in studied complexes. Quantum chemical descriptors were investigated and the anticancer activity of complexes were more than cisplatin and their ligands. Additionally, molecular docking calculations were performed in water between related complexes and a protein (ID: 3WZE). The most interact complex was found as Os complex. The interaction energy was calculated as 342.9 kJ/mol. (C) 2017 Elsevier B.V. All rights reserved.Öğe Investigations of structural, spectral and electronic properties of enrofloxacin and boron complexes via quantumchemical calculation and molecular docking(PERGAMON-ELSEVIER SCIENCE LTD, 2019) Sayin, Koray; Ungordu, AyhanQuantum chemical analyses were performed over enrofloxacin and boron complexes. The most stable isomer of enrofloxacin was examined at M062X/6-31+ G(d) level in gas phase. Structural and spectral characterizations of enrofloxacin and its complexes were performed at same level of theory. MEP maps of studied compound were calculated via ESP charges analyses. Some quantum chemical descriptors (QCDs) were calculated to determine the non-linear optical (NLO) and biological reactivity of studied molecules. Furthermore, molecular docking calculations between boron complexes and a protein (ID: 2ITN and 2ITV) were done. ADME analyses were done in the determination of the best drug candidate. As a result, complex (3) was found as the best in the NLO applications and it was found that complex (1) and (3) have similar biological reactivity in lung cancer treatment. (C) 2019 Elsevier B.V. All rights reserved.Öğe Organic light-emitting diode behaviors of some synthesized platinum(II)-based complexes(Wiley, 2023) Ungordu, AyhanOrganic light-emitting light diodes (OLEDs) have been increasingly used in displays, replacing liquid-crystal displays (LCD) and light-emitting diodes (LEDs) panels. The increase in commercial use of OLED has led to the search for OLED with high performance. For that reason, the OLED properties of monomers and dimers of some synthesized platinum(II)-based complexes were estimated by using different computational chemistry tools with different codes. The electron/hole reorganization energies, the adiabatic/vertical ionization potentials, the adiabatic/vertical electron affinities, the chemical hardness values, the dipole moments, the frontier orbital shapes/energy levels, the energy gaps, the emission wavelengths, spin-orbit matrix elements, the rates of reverse intersystem crossing and intersystem crossing of the investigated complexes were determined. From the theoretically obtained data, it was found that Pt(hppz)(2) and Pt(fppz)(2) complexes can be used as electron transfer material. Furthermore, it was stated that Pt(f2bipz)(bpy) is both electron-blocking layer and hole blocking layer materials. Moreover, it was noted that that PtOEP complex can be utilized as a good electron injection layer and hole injection layer material. Addition to these, it was emphasized that that Pt(f2bipz)(bpy) can be considered as a good candidate for near infrared organic light emitting diodes and thermal activated delayed fluorescent organic light emitting diodes. In light of computational chemistry, it should be expected that the study will provide a great contribution to studies related to organic light emitting diodes.Öğe Quantum chemical calculations on sparfloxacin and boron complexes(Elsevier, 2019) Ungordu, Ayhan; Sayin, KorayDensity functional theory calculations were performed with M06-2X/6-31 + G(d) to examine the structural and spectral features of sparfloxacin and its boron complexes and to reveal their non-linear optical and biological activities. The molecular electrostatic potential analysis was carried out on the deprotonated sparfloxacin system using ESP charge analyses to examine the surface reactivity and to show. Our results suggest that quantum chemical parameter rankings were indicated that dibromosparfloxacinateboron(III) complex could be a good candidate for NLO applications. Furthermore, molecular docking calculations between boron complexes and proteins (ID: 2ITN and 2ITV) were performed. As a result, the hydrogen bond (-F atom - A-745: LYS-2HZ) between complex (1) and 2ITN was determined. The interaction energies between difluorosparfloxacinateboron (I) and target proteins (2ITN and 2ITV) were calculated as - 473.4 and - 335.9 kJ mol(-1), respectively. This complex was found as the best drug candidate for lung cancer.Öğe The solvent (water) and metal effects on HOMO-LUMO gaps of guanine base pair: A computational study(ELSEVIER SCIENCE INC, 2017) Ungordu, Ayhan; Tezer, NurtenThe most stable structures of guanine dimer and metal-mediated guanine base pair complexes were determined both in vacuum and solvent (water). Density functional theory (DFT) method is generally used in the calculations. The calculations of systems containing C, H, N, O is described by 6-311 + +G(d,p) basis set and LANL2DZ basis set is used for transition metals. Some geometrical parameters, the LUMO, HOMO energy levels and energy gaps of compounds are calculated. Hydrogen bond stabilization energies in dimer and charge transfer in metal complexes are also determined using NBO analysis. The solvent and metal effects on energy gaps of molecules are found. Cu-mediated guanine complex can be preferred for nanotechnological applications due to its good electronic properties. (C) 2017 Elsevier Inc. All rights reserved.Öğe The design of push-pull substituted coronene molecules for optoelectronic applications(Elsevier Science Sa, 2023) Demir, Cihan; Ungordu, AyhanThe optoelectronic and electronic properties of coronene ([6]circulene) and push-pull coronene molecules were predicted by using different computational chemistry programs. For this aim, the electron/hole reorganization energies, the adiabatic/vertical ionization potentials, the adiabatic/vertical electron affinities, the chemical hardness values, the frontier orbital shapes and energy levels of the coronene and its derivatives were obtained at B3LYP/6-31G(d) level. Then the energies of the studied molecules in S0, S1, and T1 states were calculated at PBE0/TZP level. From the obtained results, the emission values and TADF parameters of the investigated compounds were determined. Based on the theoretically obtained results, it was found that 6ethynyl-coronene and 12ethynyl-coronene molecules can be used as electron transfer materials and 6cyano-coronene and 12cyano-coronene compounds can be utilized as hole transfer materials. Additionally, it was noted that 6NO2coronene and 12NH2-coronene derivatives can be good candidates for electron blocking materials, while 6NH2coronene and 12NH2-coronene molecules can be utilized as hole blocking materials. Furthermore, it was emphasized that both 6NH2-coronene and 12NH2-coronene molecules can be good candidates as both electron injection and hole injection materials. Lastly, it was reported that 6ethynyl-coronene and 12cyano-coronene structures can be considered the most suitable candidates for near infrared organic emitting diodes.Öğe The detailed investigation on OLED features of some purely organic TADF materials(Elsevier, 2024) Ungordu, AyhanComputational chemistry has been a useful tool used in the design of new materials with desired properties utilized in organic optoelectronic structures such as organic light-emitting light diode (OLED) devices. In this article, comprehensive theoretical research using density functional theory (DFT) has been conducted on the OLED design of some pure organic molecules called DF materials. Firstly, the single point energies in different states of investigated DF molecules were determined at B3LYP/6-31 G(d) level in Gaussian program. From obtained the single point energies, the reorganization energy, the ionization potential, the electron affinity, and the chemical hardness values of the materials investigated were calculated. Additionally, the ground state molecular dipole moments, the frontier orbital shapes and the frontier orbital energy levels of the titled molecules were also achieved at same level. Secondly, the geometries and energies of the ground state (S0), the lowest singlet (S1) and triplet (T1) excited states of investigated DF compounds were defined at B3LYP/TZP level in Amsterdam Modeling Suite (AMS) program. The spin-orbit coupling matrix elements (SOCMEs), Marcus reorganization energies, the rates of reverse intersystem crossing (kRISC), the fluorescence and phosphorescence emission wavelengths of the studied DF materials were computed with the help excited states. Within the framework of theoretically acquired data, it was found that only DF3 and DF4 molecules could be used as electron transport layer material, whereas all investigated DF molecules can be utilized as hole transport layer material. Addition to this, it was emphasized that only DF3 and DF4 can be suggested as ambipolar materials. Additionally, an OLED structure in the form of ITO/DF2///DF3/Li, it was determined that DF2 and DF3 molecules could be used as hole injection layer and electron injection layer materials, respectively. Moreover, it was estimated that DF5 molecule could be preferred as a good electron blocking layer material. Finally, it was predicted that that DF4 could be used as a perfect candidate for NIR TADF OLED materials.Öğe The performance of Cu-mediated metal-DNA parts for nanowires: DFT and NEGF-DFT studies(Elsevier, 2020) Ungordu, AyhanThe optimized structures of Cu-mediated metal-DNA parts formed from pyridine(pyridine-2,6-dicarboxylato) copper(II) (Dipic-Cu-Py), pyridine(pyridine-2,6-dicarboxamido)copper(II) (Dipam-Cu-Py), bis(8-hydroxyquinolinato)copper(II) (HQ-Cu-HQ), and N,N '-ethylenebis(salicylideneiminato)copper(II) (Sal-Cu-Sal) complexes were determined by B3LYP functional with 6-311++G(d,p)-LANL2DZ (Cu) basis sets. The geometric parameters of the mentioned molecules were found and their HOMO, LUMO and NBO analyses were performed. According to energy gaps of the investigated complexes, HQ-Cu-HQ parts were found as the best conductor complex. However, the effect of sugar and phosphate groups on the energy gaps of HQ-Cu-HQ base pairs could not be determined. For that reason, NEGF-DFT calculations for some Cu-mediated M-DNA parts were carried out. NEGF results showed that the electrical conductivities of HQ-Cu-HQ base pairs were quite high, and the sugar and phosphate groups significantly reduced their conductivities. The HQ-Cu-HQ base pairs without the sugar and phosphate groups were estimated as good candidates for nanowires.Öğe Theoretical insight on electronic and optical properties of some phosphorescent iridium(III) complexes for organic light-emitting diode devices(Elsevier Science Sa, 2024) Mahmood, Sangar Mohammed; Ungordu, AyhanOrganic light-emitting diode (OLED) structures have been extensively investigated because of their potential applications in various fields. It is known that organic or metal-mediated organic compounds are used in the layers of OLEDs. Within OLED materials, iridium(III) compounds have attract much attention owing to their many advantages. Therefore, we predicted the OLED behaviors of twenty-five phosphorescent iridium(III) complexes using theoretical chemical methods. All theoretical calculations were performed with the B3LYP hybrid functional using Gaussian 16 and Amsterdam Modeling Suite 2023 programs. While the 6-31G(d) basis set for non-metal atoms and LANL2DZ basis set for iridium metal was preferred in the computations carried out by using Gaussian program, whereas in the calculations performed with the Amsterdam Modelling Suite program, the TZP basis set was used for all atoms. From the theoretically obtained results, it is seen that Ir6, Ir7, Ir22-Ir25 complexes can be proposed as good candidate for hole injection layer materials in OLED based on indium tin oxide as an anode. Within complexes investigated, it has been determined that Ir16 and Ir17 complexes are the most suitable candidates for electron transport layer materials, whereas Ir16 complex can be used as both a hole transfer layer and ambipolar materials. Furthermore, it has been predicted that Ir4, Ir7, Ir8, and Ir23 complexes could be preferred as hole blocking layer compounds. From the detailed analysis of the singlet- triplet transitions of the complexes studied, it could be said that all iridium(III) complexes investigated could be used as highly efficient phosphorescent OLED molecules.
