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Öğe Ab Initio Insight into the Interaction of Metal-Decorated Fluorinated Carbon Fullerenes with Anti-COVID Drugs(Mdpi, 2022) Katin, Konstantin P.; Kochaev, Alexey I.; Kaya, Savas; El-Hajjaji, Fadoua; Maslov, Mikhail M.We theoretically investigated the adsorption of two common anti-COVID drugs, favipiravir and chloroquine, on fluorinated C-60 fullerene, decorated with metal ions Cr3+, Fe2+, Fe3+, Ni2+. We focused on the effect of fluoridation on the interaction of fullerene with metal ions and drugs in an aqueous solution. We considered three model systems, C-60, C60F2 and C60F48, and represented pristine, low-fluorinated and high-fluorinated fullerenes, respectively. Adsorption energies, deformation of fullerene and drug molecules, frontier molecular orbitals and vibrational spectra were investigated in detail. We found that different drugs and different ions interacted differently with fluorinated fullerenes. Cr3+ and Fe2+ ions lead to the defluorination of low-fluorinated fullerenes. Favipiravir also leads to their defluorination with the formation of HF molecules. Therefore, fluorinated fullerenes are not suitable for the delivery of favipiravir and similar drugs molecules. In contrast, we found that fluorine enhances the adsorption of Ni2+ and Fe3+ ions on fullerene and their activity to chloroquine. Ni2+-decorated fluorinated fullerenes were found to be stable and suitable carriers for the loading of chloroquine. Clear shifts of infrared, ultraviolet and visible spectra can provide control over the loading of chloroquine on Ni2+-doped fluorinated fullerenes.Öğe Ab initio Study of Hydrogen Adsorption on Metal-Decorated Borophene-Graphene Bilayer(Mdpi, 2021) Grishakov, Konstantin S.; Katin, Konstantin P.; Kochaev, Alexey I.; Kaya, Savas; Gimaldinova, Margarita A.; Maslov, Mikhail M.We studied the hydrogen adsorption on the surface of a covalently bonded bilayer borophene-graphene heterostructure decorated with Pt, Ni, Ag, and Cu atoms. Due to its structure, the borophene-graphene bilayer combines borophene activity with the mechanical stability of graphene. Based on the density functional theory calculations, we determined the energies and preferred adsorption sites of these metal atoms on the heterostructure's borophene surface. Since boron atoms in different positions can have different reactivities with respect to metal atoms, we considered seven possible adsorption positions. According to our calculations, all three metals adsorb in the top position above the boron atom and demonstrate catalytic activity. Among the metals considered, copper had the best characteristics. Copper-decorated heterostructure possesses a feasible near-zero overpotential for hydrogen evolution reaction. However, the borophene-graphene bilayer decorated with copper is unstable with respect to compression. Small deformations lead to irreversible structural changes in the system. Thus, compression cannot be used as an effective mechanism for additional potential reduction.Öğe All-Nitrogen Cages and Molecular Crystals: Topological Rules, Stability, and Pyrolysis Paths(Mdpi, 2020) Katin, Konstantin P.; Merinov, Valeriy B.; Kochaev, Alexey I.; Kaya, Savas; Maslov, Mikhail M.We combined ab initio molecular dynamics with the intrinsic reaction coordinate in order to investigate the mechanisms of stability and pyrolysis of N-4 divided by N-120 fullerene-like nitrogen cages. The stability of the cages was evaluated in terms of the activation barriers and the activation Gibbs energies of their thermal-induced breaking. We found that binding energies, bond lengths, and quantum-mechanical descriptors failed to predict the stability of the cages. However, we derived a simple topological rule that adjacent hexagons on the cage surface resulted in its instability. For this reason, the number of stable nitrogen cages is significantly restricted in comparison with their carbon counterparts. As a rule, smaller clusters are more stable, whereas the earlier proposed large cages collapse at room temperature. The most stable all-nitrogen cages are the N-4 and N-6 clusters, which can form the van der Waals crystals with densities of 1.23 and 1.36 g/cm(3), respectively. The examination of their band structures and densities of electronic states shows that they are both insulators. Their power and sensitivity are not inferior to the modern advanced high-energy nanosystems.Öğe Anisotropic Carrier Mobility and Spectral Fingerprints of Two- Dimensional ?-Phosphorus Carbide with Antisite Defects(Amer Chemical Soc, 2023) Katin, Konstantin P.; Maslov, Mikhail M.; Nikitenko, Vladimir R.; Kochaev, Alexey I.; Kaya, Savas; Prezhdo, Oleg, VWe apply density functional theory to study carrier mobility in a gamma-phosphorus carbide monolayer. Although previous calculations predicted high and anisotropic mobility in this material, we show that the mobility can be significantly influenced by common antisite defects. We demonstrate that at equilibrium concentrations defects do not inhibit carrier mobility up to temperatures of 1000 K. However, defects can change the mobility at high nonequilibrium concentrations of about 10-4 to 10-2 defects per atom. At the low end of this concentration range, defects act as traps for charge carriers and inhibit their mobility. At the high end of this range, defects change the effective carrier masses and deformation potentials, and they can lead to both an increase and a decrease in mobility. We also report the Raman and IR spectra associated with antisite defects. We predict new vibrational modes and shifts of the existing modes due to the defects.Öğe A benzimidazolium salt as effective corrosion inhibitor against the corrosion of mild steel in acidic medium: experimental and theoretical studies(2022) Şahin, Neslihan; Kaya Savaş; Aydın, Özkan; Katin, Konstantin P.; Chaouiki, Abdelkarim; Gürbüz, Nevin; Özdemir, İsmail; Farsak, MuratA new benzimidazolium salt (1-Allyl-3-(2,3,5,6-tetramethylbenzyl)- 5,6-dimethylbenzimidazoliumchloride) is characterized by using 1H NMR and 13C(1H) NMR spectroscopies. The corrosion inhibition performance of benzimidazolium salt for mild steel in an acidic medium is investigated with the help of both experimental and theoretical tools. The experimental part of inhibition analysis includes the use of electrochemical impedance spectroscopy (EIS), linear sweep voltammetry, potentiodynamic polarization techniques, and surface characterizations are made. In the theoretical part, Density Functional Theory calculations are performed to discuss the corrosion inhibition efficiency using quantum chemical parameters. Molecular Dynamic Simulation calculation is made to analyze adsorption properties and characteristics of synthesized molecules on mild steel. Experimental studies show that the inhibition efficiency is calculated as 97.6% from EIS results for 5 10 3 M inhibitor. Both experimental analyses and theoretical calculations proved that the studied inhibitor molecule is exhibiting higher inhibition efficiency.Öğe Computational evaluation of Ni@B12N12 and Ti@B12N12 endohedral clusters as carriers for melphalan and sulforaphane anticancer drugs(Elsevier B.V., 2025) Gürer, Eda Sönmez; Kaya, Savas; Katin, Konstantin P.We present a density functional theory study of the reactivity of M@B12N12 (M = Ni, Ti) clusters in aqueous media and their interaction with melphalan and sulforaphane anticancer drugs. In contrast to previous studies, we obtained a strongly exothermic trapping of metal atoms inside the B12N12 cage. Analysis of the radial distribution function shows that both Ni and Ti atoms distort the cage, but this effect is stronger for titanium. Clear changes in the infrared and ultraviolet/visible spectra provide easy identification of the endohedral complex formation. The distortion of the both geometrical and electronic structures of BN cage leads to a stronger bonding of M@B12N12 to hydrogen, influencing the pH-sensitivity of the endohedral cluster. Nickel weakly changes the binding energy of the carrier to both considered drugs, while the effect of titanium on this energy is very significant. Endohedral doping offers a way for achieving application-appropriate activity and selectivity of the drug delivery system based on the M@B12N12 carrier. © 2025 Elsevier B.V.Öğe Covalently Bonded 1D Chains and 2D Networks From Si-Doped CL-20: Computational Study(Springer/Plenum Publishers, 2025) Gimaldinova, Margarita A.; Maslov, Mikhail M.; Kaya, Savas; Katin, Konstantin P.To discover high-energy-density materials with characteristics superior to current models, it is necessary to study a wide range of potential structures. A promising representative of new derivatives of the class of high-energy compounds is silicon-substituted molecules CL-20, which have a reactivity and kinetic stability close to pure CL-20 but have a higher density and energy release. Low-dimensional covalent SiCL-20 nanostructures based on silicon analogue of the classical CL-20 high-energy molecule are considered in this work. Covalent nanostructures may have advantages over molecular crystals due to their special properties, such as higher packing density and kinetic stability. It has been established that silicon-substituted CL-20 molecules can connect through CH2 molecular bridges into covalent structures. Geometrical parameters, energy characteristics, electronic properties, and quantum chemical reactivity descriptors for several representatives of 1D and 2D systems based on Si5CL-20 have been calculated using density functional theory. The skeleton of each silicon fragment of the CL-20 system undergoes small changes when combined into covalent chains and networks. Still, the systems retain their consistency, and the effective diameter of the silicon frameworks in the nanostructure takes average values from 4.300 to 4.462 & Aring;. The binding energy of nanostructures increases with the number of silicon CL-20 fragments in the system. The binding energies for a single silicon molecule CL-20 and a double chain SiCL-20 consisting of 12 fragments are 3.846 and 4.077 eV/atom, respectively. Thus, the silicon nanostructures become more thermodynamically stable with increasing the size and dimension of the compound. The study of electronic characteristics made it possible to establish that the value of the HOMO-LUMO gap decreases with an increasing number of fragments in the system, and the considered SiCL-20 covalent molecules can be classified as wide-gap semiconductors, like their classical CL-20 analogues. For example, the values of the HOMO-LUMO gaps for silicon derivatives of CL-20 with dimensions 1 x 1, 6 x 1, 6 x 2, and 4 x 3L are 5.601, 4.378, 4.004, and 3.882 eV respectively. Despite their highly stressed skeleton, they are stable enough to be considered for energy applications and are promising candidates for building blocks of high-energy materials and fuels.Öğe Dual S-scheme Bi2MoO6/g-C3N4/Ag2MoO4 ternary heterojunction: Interfacial charge transfer, broadband spectrum, enhanced redox ability(Elsevier, 2024) Hasija, Vasudha; Khan, Aftab Aslam Parwaz; Sonu; Katin, Konstantin P.; Kaya, Savas; Singh, Pardeep; Raizada, PankajA ternary heterojunction bearing Bi2MoO6 and g-C3N4 is deposited on Ag2MoO4 for the photocatalytic degradation of sulfamethoxazole (SMX) antibiotic. Though the hydrothermal synthesis is non-directional, the dual Sscheme heterojunction formation is governed by the g-C3N4 serving as an electron bridge between Bi2MoO6 and Ag2MoO4. The potent strong interaction with both Bi2MoO6 and Ag2MoO4 facilitates high oxidation and reduction potential. The optimized Bi2MoO6/g-C3N4/Ag2MoO4 heterojunction with extended visible light absorption exhibits 96 % SMX degradation efficiency within 240 min of irradiations. The dual S-scheme configuration endows in-built electric field with vigorous driving force for charge carrier separation. The charge transfer mechanisms were validated by the photoluminescence results. Bi2MoO6/g-C3N4/Ag2MoO4 MoO 4 heterojunction demonstrates pseudo-first order kinetics with 0.143 kmin(-1) for SMX degradation and ternary photo-catalyst 83 % degraded SMX after successive five cycles. In the formed dual S-scheme Bi2MoO6/g-C3N4/Ag2MoO4 heterojunction, (OH)-O-center dot and center dot O-2(-) radicals were the main reactive species for SMX degradation. This research contributes to the formation of stable multicomponent photocatalytic systems.Öğe Effect of Hemp Fiber Addition on Mechanical Properties of Acrylic Resin: Coupled Experimental and Theoretical Study(Korean Fiber Soc, 2022) Bolayir, Giray; Soygun, Koray; Avsar, Melek Kilic; Boztug, Ali; Kaya, Savas; Katin, Konstantin P.We present experimental and theoretical study of the fiber-matrix composites based on polymethyl methacrylate (PMMA) prosthetic material. Hemp fibers of different lengths and concentrations were added to PMMA. In total, ten groups of composite samples were prepared. Flexural strength test was performed for each sample. We found that the addition of hemp fibber significantly change the mechanical properties of pristine PMMA. The nature of the interaction between PMMA and hemp fiber were further investigated with scanning electronic microscopy, infrared spectrometry and density functional theory. This interaction were described atomistic level in terms of quantum descriptors of reactivity, such as chemical potential, electronegativity, chemical hardness and softness, electrophilicity, electrodonating and electroaccepting powers and electrons transfer. We observed the formations of strong hydrogen bonds between the matrix and fibers, which explain the observed improvement of mechanical properties.Öğe Electronic and optical characteristics of graphene on the molybdenum ditelluride substrate under the uniform mechanical stress(Elsevier Science Sa, 2023) Kulyamin, Pavel A.; Kochaev, Aleksey I.; Maslov, Mikhail M.; Flores -Moreno, Roberto; Kaya, Savas; Katin, Konstantin P.The study presents the effect of opening a semiconductor gap in graphene on the molybdenum ditelluride substrate under mechanical stresses using the density functional theory. It has been shown that uniform compression cannot only open the gap due to graphene sheet deformation but also adjust the gap size depending on the compression strength. The maximum gap found was 0.8 eV when the structure was compressed by 8 %, which is confirmed by further analysis of the UV-vis spectrum. Uniform stretching in contrast does not lead to a significant gap opening. The binding energy of the graphene sheet with the molybdenum ditelluride substrate does not change significantly when mechanical stresses are applied. An additional analysis of the Raman and IR spectra will make it possible to determine the degree of compression of graphene on a molybdenum ditelluride substrate in the experiment. In this case, the corresponding modes mainly correspond to vibrations of carbon atoms in the graphene plane or perpendicular to the substrate. The substrate itself does not make a significant contribution to these vibrational modes.Öğe Experimental and theoretical observations in a mixed mode dispersive solid phase extraction of exogenous surfactants from exhaled breath condensate prior to HPLC-MS/MS analysis(Elsevier, 2023) Khoubnasabjafari, Maryam; Altunay, Nail; Tuzen, Mustafa; Katin, Konstantin P.; Farajzadeh, Mir Ali; Kaya, Savas; Hosseini, MohamadbagherA mixed mode dispersive solid phase extraction method was introduced for the extraction of three lung surfactants from exhaled breath condensate samples. Considering the trends to green analytical chemistry, organic polymers including polystyrene (PS), polymethylmethacrylate (PMMA-15 K), and polymethylmethacrylate (PMMA-45 K) were utilized as the sorbent for extraction of the analytes. The extraction capability for each polymer toward the studied analytes was evaluated using simplex centroid design. Based on the results, a mixture of sorbents consisting of PS, PMMA-15 K, and PMMA-45 K mixture with the mass ratio of 1:2:1: w/w/w was selected as the suitable sorbent. The effective parameters influencing the method's efficiency were investigated and optimized. Based on the figure of merit for the developed method, the calibration curves were linear in the concentration range of 0.76-10 0 0 ng mL -1 and limits of detection were from 0.09 to 0.19 ng mL -1 . The method repeatability was investigated at three concentrations as inter- and intra-day precisions and the obtained data showed that they were in the ranges of 5.2-9.1 and 4.2-8.9%, respectively. The enrichment factors were in the range of 88-100. The developed method was successfully employed in the analysis of the surfactants in the exhaled breath samples of three premature infants collected from the expiratory circuits of the mechanical ventilators. The nature of the chemical interactions with PMMA-PS complex system of the surfactants was investigated through Density Functional Theory calculations. Calculated binding energies showed that PMMA-PS complex system exhibit high performance in the extraction of lung surfactants. The most powerful interaction is between PMMA-PS complex system and 1-palmitoyl-2-oleoylsn-glycero-3-phosphocholine.(c) 2023 Elsevier B.V. All rights reserved.Öğe Fabrication of a dual Z-scheme Ag3PO4/g-C3N4/Bi2MoO6 ternary nanocomposite for effective degradation of methylene blue dye(Springer, 2024) Chauhan, Akanksha; Khan, Aftab Aslam Parwaz; Sudhaik, Anita; Kumar, Rohit; Katin, Konstantin P.; Kaya, Savas; Raizada, PankajMethylene blue is a recognized carcinogen with detrimental effects on both people and marine life. Henceforth, in this study, the photocatalytic activity of Ag3PO4/g-C3N4/Bi2MoO6 (AP/GCN/BMO) photocatalyst was investigated for the degradation of MB dye from an aqueous system. g-C3N4, BMO and AP photocatalysts bare photocatalysts were synthesized via thermal polycondensation, hydrothermal and co-precipitation methods, respectively. Similarly, binary (GCN/BMO) and ternary heterojunctions (AP/GCN/BMO) was constructed through in-situ hydrothermal and co-precipitation methods, respectively. Morphological and structural analysis validated close interaction amongst Ag3PO4, g-C3N4, and Bi2MoO6 photocatalysts. Furthermore, density functional theory simulations were employed to explore the structural and electronic properties of the bare (Ag3PO4, g-C3N4, and Bi2MoO6) photocatalysts. The photocatalytic degradation experiments revealed that AP/GCN/BMO exhibited highest adsorption and photocatalytic degradation efficacy of methylene blue (MB) dye pollutant as compared to other photocatalysts. The achieved MB dye degradation efficiency of dual Z-scheme AP/GCN/BMO ternary photocatalyst was approx. ~94% within 60 min under visible light exposure which was much greater than pristine and binary photocatalysts. This higher efficiency was accredited to dual Z-scheme type of charge transfer route which boosted photocarriers charge separation and transferal rate. Furthermore, through scavenging experiment, the confirmed reactive species in this type of charge transfer route were •O2? and •OH radicals that efficiently degraded MB dye pollutant. Additionally, the ternary photocatalyst demonstrated good stability and recyclability for up to five successive catalytic cycles with 81% degradation efficiency. The current work extends our understanding of photocatalytic degradation by providing novel strategies for pollutant degradation that successfully degrade contaminants. Also, it promotes the development of more efficient, environmentally friendly waste treatment methods that uses solar/light energy. Graphical Abstract: (Figure presented.) © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.Öğe Headspace ?-solid phase extraction of 1,4-dioxane and 2-methyl-1,3-dioxolane from shampoo samples in a home-mode device and large volume injection of deep eutectic solvent: Theoretical and experimental studies(Elsevier, 2022) Mogaddam, Mohammad Reza Afshar; Altunay, Nail; Tuzen, Mustafa; Katin, Konstantin P.; Nemati, Mahboob; Lotfipour, FarzanehIn the current study, a headspace micro solid-phase extraction was developed for extraction of 1,4-dioxane and 2-methyl-1,3-dioxolane from shampoo samples. After extraction, the quantities of analytes were determined using the large volume injection method followed by gas chromatography-flame ionization detector. Octadecylsilane, menthol: formic acid deep eutectic solvent, and 1,3-dioxane were used as adsorbent, eluent, and internal standard, respectively. Under optimum conditions, linear ranges for target analytes were from 0.30 to 5000 ng mL-1, and 0.43-5000 ng mL-1 with correlation coefficients 0.9972. The limits of detection were 0.08 and 0.11 ng mL-1 for 1,4-dioxane and 2-methyl-1,3-dioxolane, respectively. The limits of quantification were 0.28 and 0.43 ng mL-1 for 1,4-dioxane and 2-methyl-1,3-dioxolane, respectively. The intra- and inter-day precisions for target analytes at the spiked level of 25 ng mL-1 were < 4.2%. The feasibility of the recommended procedure was successfully tested for the extraction and determination of 1,4-dioxane and 2-methyl-1,3-dioxolane in shampoo samples. The extraction recoveries were ranged from 89 to 90% with relative standard deviations<5.1%. The nature of the interactions between studied chemical species was investigated in the light of conceptual density functional theoretical calculations. As to conclude, it was seen that experimental observations are compatible with the theoretical explanations made according to hard and soft (Lewis) acids and bases Principle.Öğe Inhibition performances of new pyrazole derivatives against the corrosion of C38 steel in acidic medium: Computational study(Elsevier B.V., 2024) Kaya, Savaş; Siddique, Farhan; Isin, Dilara Ozbakir; Katin, Konstantin P.; Asati, Vivek; Berisha, AvniCorrosion inhibition performances of two new pyrazole derivatives, namely 5-(4-dimethylamino)phenyl)-3-(4-dimethylamino)styryl)-4,5-dihydro-1H-pyrazole-1-carbothio amide (P1) and 5-(4-dimethylamino)phenyl)-3-phenyl-4,5-dihydro-1H-pyrazole-1-carbothio amide (P2) against the corrosion of carbon steel in acidic medium are theoretically investigated by combination of the density functional theory with the molecular dynamics approach. Additionally, the toxicity and solubility of the aforementioned molecules were investigated. Quantum chemical parameters of considered molecules (calculated energy levels of HOMO and LUMO molecular orbitals as well as the gap between them, hardness, softness, chemical potential, electronegativity, electrophilicity index, nucleophilicity, electro donating power, electro accepting power, polarizability, dipole moment, metal-inhibitor interaction energy, the fraction of electrons transferred from inhibitors to metal surface, back-donation energy, Fukui indices) were calculated at B3LYP/SVP, CAM-B3lyp/TZVP and ?B97XD/Def2-TZVP levels of theory. Comparative calculations were performed in the gaseous phase and in the aqueous solutions. The adsorption behavior of the mentioned molecules on the Fe (110) surface was investigated with the molecular dynamics. Both considered molecules demonstrates high adsorption energies on steel surface, low toxicity and high solubility. P1 is found to be more efficient in hydrochloric acid, whereas P2 molecule is found to be more efficient in sulfuric acid. © 2024Öğe Interaction of dopants and functional groups adsorbed on the carbon fullerenes: Computational study(Elsevier, 2020) Salem, Mahmoud A.; Katin, Konstantin P.; Kaya, Savas; Kochaev, Alexei I.; Maslov, Mikhail M.We apply density functional theory to study the effective interaction between dopant atoms (B, N, Si, P) and functional groups (H, F, Cl, OH) on the surface of carbon fullerenes. Both dopant atoms and functional groups strongly interact through the carbon cage even in diametrically opposite positions. Interaction energies distribute in a wide range from 0.1 to 2 eV and non-monotonically depend on fullerene size and distance between dopants or functional groups. Such interaction cannot be described as a simple Coulomb repulsion or sum of dopants binding energies and cage strain energy. We identify some general trends in relative positions of dopants or functional groups in low-energy isomers. Para position of two functional groups is the most feasible for C-60 and larger cages. For lower fullerenes, ortho or other spaced positions may be more preferable. The interaction of foreign atoms embedded into the carbon cages is more complicated. The best relative positions intricately depend on the cage size and chemical nature of dopants. As a rule, ortho and para locations are feasible for C-60 and larger cages. However, some exceptions are observed. The effect of thermal vibrations on the considered interactions in doped or functionalized fullerenes is negligible in the temperature range from 300 to 1000 K.Öğe Interaction of pristine and novel graphene allotropes with copper nanoparticles: Coupled density functional and molecular dynamics study(Elsevier Science Sa, 2023) Katin, Konstantin P.; Kochaev, Alexey I.; Bereznitskiy, Igor V.; Kalika, Elizaveta B.; Kaya, Savas; Flores-Moreno, Roberto; Maslov, Mikhail M.We combined the density functional theory and classical molecular dynamics to study the time evolution and thermal stability of copper nanoparticles wrapped in graphene flakes. We observed a strong attraction between nanoparticles and flakes, which was underestimated in many previous simulations. We found that the twoparameter Lennard-Jones potential with parameters & epsilon; = 0.074 eV and r0 = 3.310 & ANGS; reproduces DFT data better than other empirical potentials. We confirmed that a nanoparticle could be held reliable inside a graphene flake. The graphene-coated copper system remains stable over the temperature range of 300-1000 K. In addition to pristine graphene, we considered several strained allotropes containing pentagons, as well as heptagons, octagons, and nanometer-sized pores. Strained allotropes interact with copper nanoparticles approximately twice more strongly as compared to pristine graphene. Molecular dynamics revealed nanoparticle flattening due to strong interaction with graphene allotropes at elevated temperatures. The wettability of graphene with respect to copper strongly depends on the sheet structure and can vary significantly for different allotropes. The results may be useful for further research on copper-graphene composites, which are suitable for catalytic and biomedical applications.Öğe IR spectra simulations by anharmonic DFT and CDFT-saturated and unsaturated fatty acids of Siberian sturgeon (Acipenser baerii Brandt,1869)(Academic Press Inc Elsevier Science, 2024) Aktas, Ayse Burcu; Dastan, Taner; Gorgun, Salih; Gunlu, Ali; Ercan, Ertan; Katin, Konstantin P.; Kaya, SavasThe Siberian sturgeon is one of the most remarkable species in the field of aquatic biology which also has ecological importance, commercial significance, and nutritional characteristics. The purpose of this study is to determine the fatty acid content of different organs of Siberian sturgeon through both theoretical and experimental techniques to compare oxidative stability of the samples in terms of fatty acid profile. For this purpose, the fatty acid content of flesh, brain, caviar and liver of sturgeon was determined by gas chromatography and the middle infrared spectra of tissues were collected by an infrared spectrofotometer. The fatty acid content of samples was also computed by anharmonic DFT and CDFT calculations using IR spectra. Oleic acid was the most abundant fatty acid in all tissues. All tissues accumulated by docosahexanoic, eicosapentanoic and linolenic acids. The PCA model was able to classified the tissues with respect to fatty acid contents. Comprehensive anharmonic DFT calculations were performed to better understand the fatty acid of samples at the atomistic level and to predict the spectra of more complex food samples with varying fatty acid compositions. Oxidative stabilities of fatty acids were also investigated through Conceptual DFT based computations. Maximum Hardness and Minimum Electrophilicity Principles accurately predicted saturated and unsaturated fatty acids of sturgeon as the experimental data revealed.Öğe Low-strained carbon monolayers with pentagonal cycles for lithium storage: Precursor analysis, self-assembly simulation and properties prediction(Elsevier, 2025) Katin, Konstantin P.; Kochaev, Alexei I.; Kaya, Savas; Orlov, Konstantin I.; Berezniczcky, Igor, V; Maslov, Mikhail M.We formulated general requirements for hydrocarbon precursors that can easily self-assemble into a defect-free 2D monolayer on a metal substrate by a one-stage process. Based on these requirements, we proposed two suitable precursors contained pentagonal cycles, which were computationally characterized. Classical molecular dynamics shown that they can self-assemble on Cu(111) and Au(111) substrates under ambient conditions, while self-assembly on Ag(111) requires elevated temperature. Probable defect appearing during self-assembly was detected. The resulting 2D monolayers have pores about one nanometer in diameter. Nevertheless, they exhibit high structural stability and metallic conductivity. According to density functional theory calculations, they can be elastically deformed by about 8%, and their elastic constants are comparable to those of graphynes. The presence of pores in the carbon monolayers allows the adsorption of up to 17.2 at. % lithium. Ab initio molecular dynamics confirms the reliable loading of lithium on the monolayers. The presence of pores, absence of highreactive multiple C-C bonds or strained triangle/square cycles as well as excellent adsorption properties are the main advantages of the proposed monolayers in comparison with graphene and its common allotropes.Öğe New mixed-ligand iron(III) complexes containing thiocarbohydrazones: Preparation, characterization, and chemical reactivity analysis through theoretical calculations(Wiley, 2022) Kaya, Yeliz; Ercag, Ayse; Kaya, Savas; Katin, Konstantin P.; Atilla, DevrimFive new mixed ligand Fe(III) complexes, namely, [FeL1(acac)] (L1Fe), [FeL2(acac)] (L2Fe), [FeL3(acac)] (L3Fe), [FeL4(acac)] (L4Fe), and [FeL5(acac)] (L5Fe), were synthesized from the reaction of iron(III) acetylacetonate with [ONS] donor dibasic tridentate symmetrical bisthiocarbohydrazone ligands. Synthesized mixed ligand Fe(III) complexes were characterized with infrared spectra, UV-Vis spectra, mass spectra, elemental analysis, magnetic susceptibility measurements, and thermogravimetric analysis. The molar conductance measurement in DMF solution confirmed that the complexes are nonelectrolytic. TGA analysis results showed that the thermal stability of the ligands and complexes was high. Antioxidant capacity and free radical scavenging activity of the mixed ligand Fe(III) complexes were investigated using CUPRAC and the DPPH radical scavenging method. Mixed ligand Fe(III) complexes showed higher antioxidant activity than ligands and reference compound. Popular conceptual density functional parameters like hardness, electrophilicity, dipole moment, and chemical potential for new ligands and their Fe(III) complexes were calculated and discussed. Chemical reactivity and stabilities of the studied chemical systems were analyzed with the help of well-known electronic structure principles like maximum hardness principle (MHP), hard and soft acid-base (HSAB) principle, minimum polarizability principle, and minimum electrophilicity principle. L1Fe, which has the highest chemical hardness value, is the most stable complex according to MHP.Öğe Novel bromide-cucurbit[7]uril supramolecular ionic liquid as a green corrosion inhibitor for the oil and gas industry(Elsevier Science Sa, 2021) Berdimurodov, Elyor; Kholikov, Abduvali; Akbarov, Khamdam; Guo, Lei; Kaya, Savas; Katin, Konstantin P.; Verma, Dakeshwar KumarMetal corrosion is the largest problem in the oil and gas industry. Therefore, providing metallic materials with corrosion protection is an urgent task in modern research. The use of green corrosion inhibitors for corrosion protection is very important both ecologically and economically. This work is the first to introduce a novel bromide-cucurbit[7]uril (BrCU) supramolecular ionic liquid as an excellent corrosion inhibitor for the oil and gas industry. Its inhibition behaviour for carbon steel in 1 M NaCl saturated with CO2 and H2S was first fully identified through the use of thermodynamic and gravimetric analysis, electrochemical noise (EN), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM), density functional theory (DFT), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) methods. The experimental results confirmed that BrCU is an excellent environmentally friendly corrosion inhibitor for the gas and oil industry. Its inhibition efficiency was 97.54% at 100 mg/ L/0.06 mM, and it was more stable at high temperature (333 K). A Langmuir isotherm was applied to identify the adsorption character of BrCU on the metal surface. The obtained PDP data suggested that BrCU was a predominantly anodic mixed-type corrosion inhibitor. Theoretical calculations showed good correlation with the experimental results, indicating that the halogen modification in the supramolecular ionic liquid system improved the inhibition performance.
