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Journal articles on the topic 'DFT; Density Functional Theory; heterocycles'

Author: Grafiati

Published: 20 February 2023

Last updated: 31 July 2025

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1

Shigemitsu, Yasuhiro, Kaori Komiya, Naoko Mizuyama, Masayori Hagimori, and Yoshinori Tominaga. "Synthesis and TDDFT Investigation of New Maleimide Derivatives Bearing Pyrrole and Indole Ring." Research Letters in Organic Chemistry 2009 (February 12, 2009): 1–5. http://dx.doi.org/10.1155/2009/413219.

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A novel series of heterocycles were obtained through the condensation reaction of 4-methylthiomaleimides with pyrroles and indoles. The newly synthesized compounds exhibit their major electronic absorption peaks ranging 435–504 nm in solution at room temperature. Time-dependent density-functional theory (TDDFT) calculations were systematically performed in order to elucidate their structure-color relationships, using a set of exchange-correlation (XC) functionals. The TDDFT computational scheme employing PCM-TDDFT/6-31+G(d,p)//DFT/6-311G(d,p) level of theory gave qualitatively satisfactory res

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2

LI, YUANZUO, CHAOFAN SUN, and LINPO YANG. "STRUCTURES AND SPECTROSCOPIC PROPERTIES OF THREE AROMATIC HETEROCYCLIC DYE PHOTOSENSITIZERS." Journal of Theoretical and Computational Chemistry 12, no. 06 (2013): 1350055. http://dx.doi.org/10.1142/s0219633613500557.

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The ground-state structures and absorption spectra of three dyes, carbazole, phenothiazine and diphenylamine, were studied by the density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The strong absorption peak, electron transition as well as the energy levels of molecular orbitals were obtained and compared in the gas and solvent phase. Furthermore, we further calculated the effect of the expanding conjugated bridge on the absorption spectra and the energy levels of molecular orbitals. Visualized method of charge difference density (CDD) was used to show the d

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3

Fernandes, Sara, João Aires-de-Sousa, Michael Belsley, and M. Raposo. "Synthesis of Pyridazine Derivatives by Suzuki-Miyaura Cross-Coupling Reaction and Evaluation of Their Optical and Electronic Properties through Experimental and Theoretical Studies." Molecules 23, no. 11 (2018): 3014. http://dx.doi.org/10.3390/molecules23113014.

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A series of π-conjugated molecules, based on pyridazine and thiophene heterocycles 3a–e, were synthesized using commercially, or readily available, coupling components, through a palladium catalyzed Suzuki-Miyaura cross-coupling reaction. The electron-deficient pyridazine heterocycle was functionalized by a thiophene electron-rich heterocycle at position six, and different (hetero)aromatic moieties (phenyl, thienyl, furanyl) were functionalized with electron acceptor groups at position three. Density Functional Theory (DFT) calculations were carried out to obtain information on the conformatio

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4

Kaneti, Jose, Vanya Kurteva, Milena Georgieva, et al. "Small Heterocyclic Ligands as Anticancer Agents: QSAR with a Model G-Quadruplex." Molecules 27, no. 21 (2022): 7577. http://dx.doi.org/10.3390/molecules27217577.

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G-quadruplexes (GQs) have become valid targets for anticancer studies in recent decades due to their multifaceted biological function. Herewith, we aim to quantify interactions of potential heterocyclic ligands (Ls) with model GQs. For seven 4-aminoquinazolines and three 2-heteroaryl perimidines, seven of this ten-membered group so far unknown, we use routine quantum chemical modeling. As shown in the literature, a preferred mode of interaction of heterocycles with cellular structures is stacking to exposable faces of G-quadruplexes. To exploit the energy of this interaction as a molecular des

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5

Ma, Yumiao, Hafiz Saqib Ali, and Aqeel A. Hussein. "A mechanistic study on the gold(i)-catalyzed cyclization of propargylic amide: revealing the impact of expanded-ring N-heterocyclic carbenes." Catalysis Science & Technology 12, no. 2 (2022): 674–85. http://dx.doi.org/10.1039/d1cy01617b.

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Density functional theory (DFT) was applied to understand the mechanistic pathway of the gold(i)-catalyzed cyclization of propargylic amide, and to reveal the impact of expanded-ring N-heterocyclic carbenes.

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6

Younas, Sobia, Aqdas Riaz, Haq Nawaz, et al. "Characterization of three different benzimidazolium ligands and their organo-selenium complexes by using density functional theory and Raman spectroscopy." RSC Advances 13, no. 50 (2023): 35292–304. http://dx.doi.org/10.1039/d3ra04931k.

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In this study, Raman spectroscopy along with density functional theory (DFT) calculations have been performed for characterization of three different selenium-based N-heterocyclic carbene (NHC) complexes synthesized from their respective salts.

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7

Velihina, Yevheniia, Nataliya Obernikhina, Stepan Pilyo, Maryna Kachaeva, Oleksiy Kachkovsky, and Volodymyr Brovarets. "In silico study of binding affinity of nitrogenous bicyclic heterocycles: fragment-to-fragment approach." Ukr. Bioorg. Acta 2020, Vol. 15, N2 15, no. 2 (2020): 49–59. http://dx.doi.org/10.15407/bioorganica2020.02.049.

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The binding affinity of model aromatic amino acids and heterocycles and their derivatives condensed with pyridine were investigated in silico and are presented in the framework of fragment-to-fragment approach. The presented model describes interaction between pharmacophores and biomolecules. Scrupulous data analysis shows that expansion of the π-electron system by heterocycles annelation causes the shifting up of high energy levels, while the appearance of new the dicoordinated nitrogen atom is accompanied by decreasing of the donor-acceptor properties. Density Functional Theory (DFT) wB97XD/

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8

Rifaat Taher, Sardasht, and Wali Mahood Hamad. "Synthesis, characterization, density functional theory (DFT) analysis, and mesomorphic study of new thiazole derivatives." Bulletin of the Chemical Society of Ethiopia 38, no. 6 (2024): 1827–42. http://dx.doi.org/10.4314/bcse.v38i6.25.

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This study focuses on synthesizing and characterizing a new series of organic compounds with a heterocyclic core based on sulfur (thiazole). These compounds, labeled as N-(4-(4-alkoxyphenyl) thiazol-2-yl)-1-(naphthalen-2-yl) methanimine (ATNM)n, incorporate alkoxy chains of varying lengths (CnH2n+1O, n = 2, 3, 4, 5, 6, 7, 8, 9, 10, and 12) through a multi-step process. Structural analysis using FT-IR, 1H-NMR, and 13C-NMR confirmed the composition of these compounds. Theoretical calculations using density functional theory (DFT) were carried out with the B3LYP 6-311G (d,p) basis set for the ent

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9

Lalanne-Tisné, Michael, Audrey Favrelle-Huret, Wim Thielemans, João P. Prates Ramalho, and Philippe Zinck. "DFT Investigations on the Ring-Opening Polymerization of Trimethylene Carbonate Catalysed by Heterocyclic Nitrogen Bases." Catalysts 12, no. 10 (2022): 1280. http://dx.doi.org/10.3390/catal12101280.

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Organocatalysts for polymerization have known a huge interest over the last two decades. Among them, heterocyclic nitrogen bases are widely used to catalyse the ring-opening polymerization (ROP) of heterocycles such as cyclic carbonates. We have investigated the ring-opening polymerization of trimethylene carbonate (TMC) catalysed by DMAP (4-dimethylaminopyridine) and TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene) as case studies in the presence of methanol as co-initiator by Density Functional Theory (DFT). A dual mechanism based on H-bond activation of the carbonyl moieties of the monomer and a b

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10

Li, Yan, та Zhiqiang Zhang. "Mechanism and stereoselectivity in NHC-catalyzed β-functionalization of saturated carboxylic ester". RSC Advances 9, № 14 (2019): 7635–44. http://dx.doi.org/10.1039/c8ra10262g.

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To understand the mechanism and origin of stereoselectivity of [3 + 2] annulation reaction between a carboxylic ester and an isatin catalyzed by N-heterocyclic carbene (NHC), density functional theory (DFT) calculations have been carried out.

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11

Sutrisno, Andre, Andy Y. H. Lo, Joel A. Tang, et al. "Experimental and theoretical investigations of selenium nuclear magnetic shielding tensors in Se–N heterocycles." Canadian Journal of Chemistry 87, no. 10 (2009): 1546–64. http://dx.doi.org/10.1139/v09-100.

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A preliminary study involving solid-state 77Se NMR spectroscopy and first principles calculations of 77Se NMR parameters in Se–N heterocycles is reported. 77Se CP/MAS NMR spectra of the ring systems reveal expansive selenium chemical shift (CS) tensors, which are extremely sensitive to molecular geometry, symmetry, ligand substitution, and intermolecular contacts. For systems with known crystal structures, hybrid density functional theory (DFT) calculations of selenium nuclear magnetic shielding (NMS) tensors were carried out, and tensor orientations in the molecular frames examined. Additiona

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12

Dlala, Najet Aouled, Younes Bouazizi, Houcine Ghalla, and Naceur Hamdi. "DFT Calculations and Molecular Docking Studies on a Chromene Derivative." Journal of Chemistry 2021 (April 1, 2021): 1–17. http://dx.doi.org/10.1155/2021/6674261.

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Chromenes and their derivatives have been considered as an important class of oxygen-containing heterocycles. There has been an increasing interest in the study of chromenes due to their biological activity. Herein, the structural, electronic, and vibrational properties of a chromene derivative, entitled 2‐amino‐5‐oxo‐4‐phenyl‐4,5‐dihydropyrano[3,2‐c]chromene‐3‐carbonitrile and abbreviated as Chrom-D, have been reported. The FT-IR, UV-vis, and 1H-NMR and 13C-NMR chemical shifts’ measurements were recorded. The molecular geometry and the vibrational frequencies are computed in the frame of dens

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13

Ali, Hafiz Saqib, Aqeel A. Hussein, and Mohammed Obies. "Impact of counteranions on N-heterocyclic carbene gold(i)-catalyzed cyclization of propargylic amide." RSC Advances 13, no. 5 (2023): 2896–902. http://dx.doi.org/10.1039/d2ra06210k.

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14

Slodek, Aneta, Dawid Zych, Grażyna Szafraniec-Gorol, Paweł Gnida, Marharyta Vasylieva, and Ewa Schab-Balcerzak. "Investigations of New Phenothiazine-Based Compounds for Dye-Sensitized Solar Cells with Theoretical Insight." Materials 13, no. 10 (2020): 2292. http://dx.doi.org/10.3390/ma13102292.

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New D-π-D-π-A low-molecular-weight compounds, based on a phenothiazine scaffold linked via an acetylene unit with various donor moiety and cyanoacrylic acid anchoring groups, respectively, were successfully synthesized. The prepared phenothiazine dyes were entirely characterized using nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. The compounds were designed to study the relationship between end-capping donor groups’ structure on their optoelectronic and thermal properties as well as the dye-sensitized solar cells’ performance. The effect of π-conjugation enlargement by

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15

Oulhaj, Oumaima, Lamya Oubenmoussa, Hicham Essassaoui, Mohamed Bouha, and Mohamed Mbarki. "Structural, electronic, and spectroscopic properties of oxadiazole isomers in the light of DFT computational study." Current Chemistry Letters 14, no. 1 (2025): 31–40. http://dx.doi.org/10.5267/j.ccl.2024.10.004.

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Oxadiazoles, a class of nitrogen-containing heterocycles, exhibit diverse applications in pharmaceuticals, industry, and other fields. This study employs Density Functional Theory (DFT) to investigate the structural, electronic, and spectroscopic properties of four oxadiazole isomers. The B3LYP functional and the 6-311G(d,p) basis set were used for calculations. Frontier orbital energies, energy gap, chemical reactivity descriptors, dipole moment, and thermodynamic properties were computed. Additionally, IR and UV spectra were analyzed. The results indicate significant variations in electronic

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16

Fahim, Asmaa Mahmoud, Ahmad Mahmoud Farag, Mohamed Rabie Shaaban, and Eman Ali Ragab. "Synthesis and DFT study of novel pyrazole, thiophene, 1,3-thiazole and 1,3,4-thiadiazole derivatives." European Journal of Chemistry 9, no. 1 (2018): 30–38. http://dx.doi.org/10.5155/eurjchem.9.1.30-38.1675.

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Regioselective facile synthesis of innovative heterocycles from the reaction of 2-cyano-N-cyclohexylacetamide (3) with hydrazonoyl chloride (4) in basic condition afforded amino pyrazole derivative 6. The behavior of acetamide 3 with phenylisothiocyanate in DMF/KOH surveyed by addition of the α-halo ketones to yeild the corresponding thiophene derivative 13a, 13b, 16, 18 and 1,3-thiazoles 21. Reaction of intermediate potassium salt 9 with hydrazonoyl chloride 22a-e furnished the corresponding 1,2,4-thiadiazoles 24a-e. Density functional theory (DFT) calculations at the B3LYP and HF techniques

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17

Aktan, Ebru, and Tahsin Uyar. "Hetarylazopyrazolone Dyes Based on Benzothiazole and Benzimidazole Ring Systems: Synthesis, Spectroscopic Investigation, and Computational Study." Journal of Chemistry 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/8659346.

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In this study, the synthesized coupling component 1-(2-benzothiazolyl)-3-methylpyrazol-5-one reacted with diazotised heterocyclic amines to afford six novel hetarylazopyrazolone dyes. These azo dyes based on benzothiazole and benzimidazole ring systems were characterized by spectral methods and elemental analyses. The solvatochromic behaviors of these dyes in various solvents were evaluated. The ground state geometries of the dyes were optimized using density functional theory (DFT). Solvent, acid-base, and substituent influences on the wavelength of the maximum absorption were examined in det

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18

Sainz-Díaz, C. Ignacio, Misaela Francisco-Márquez, and Annik Vivier-Bunge. "Adsorption of polyaromatic heterocycles on pyrophyllite surface by means of different theoretical approaches." Environmental Chemistry 8, no. 4 (2011): 429. http://dx.doi.org/10.1071/en11055.

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Environmental contextVolatile organic compounds can adsorb to the surfaces of silicates present in atmospheric aerosols, but the mechanisms and interactions are not well understood. We compare theoretical approaches for describing the adsorption of polyaromatic heterocycles to a model phyllosilicate surface. The enthalpy and spectroscopic data for this adsorption provide valuable information for future experimental studies on these atmospheric pollutants. AbstractThe adsorption of thiophene, benzothiophene and dibenzothiophene, as models of polyaromatic heterocycles, on the (001) surface of py

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19

Mohammadi, Samaneh, Mehdi Pordel, Sadegh Allameh, and Hamed Chegini. "Synthesis of New Dyes from Imidazo[1,2-a]Pyridine: Tautomerism, Spectroscopic Characterisation, DFT/TD-DFT Calculations, Atoms in Molecules Analyses and Antibacterial Activities." Journal of Chemical Research 41, no. 3 (2017): 143–48. http://dx.doi.org/10.3184/174751917x14873588907684.

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The synthesis, optical properties, theoretical calculations and antibacterial activity of a series of new heterocyclic dyes from imidazo[1,2-a] pyridine are described. The key intermediate 2-[3-(hydroxyimino)imidazo[1,2-a]pyridin-2(3H)-ylidene]malononitrile was obtained via the nucleophilic substitution of hydrogen in 3-nitroimidazo[1,2-a]pyridine with malononitrile in basic methanol solution. Tautomerism, oxidation and alkylation studies on the dye led to the synthesis of new heterocyclic indigo-coloured, purple, and orange dyes in good yields. The structures of all newly synthesised compound

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20

Choyal, Manisha. "Structural parameters of N-heterocyclic pyridinium methylides - A DFT study." INDIAN JOURNAL OF HETEROCYCLIC CHEMISTRY 35, no. 02 (2025): 342. https://doi.org/10.59467/ijhc.2025.35.342.

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The present communication includes an investigation of the structural parameters of nitrogen ylides present in differently substituted pyridine rings generated as a chemical intermediate during the formation of functionalized indolizine derivatives via [3+2]/1,3-dipolar cycloaddition. Remarkable experimental observations such as hydrogen bonding and delocalization of charge density have been made through computational calculation based on geometry optimization of ylides.. KEYWORDS :Cycloaddition reactions, Density functional theory, N-Heterocyclic ylides, Stereoelectronic effects.

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21

Koraiem, Ahmed I., Islam M. Abdellah, Ahmed El-Shafei, Fathy F. Abdel-Latif, and Reda M. Abd El-Aal. "Synthesis, optical characterization, and TD-DFT studies of novel mero/bis-mero cyanine dyes based on N-Bridgehead heterocycles." Canadian Journal of Chemistry 97, no. 3 (2019): 219–26. http://dx.doi.org/10.1139/cjc-2018-0325.

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Novel mero/bis-mero cyanine dyes based on N-Bridgehead imidazo[1,2-g]quinolino[2,1-a][2,6]naphthyridine have been synthesized and characterized to evaluate intramolecular charge transfer (ICT) effect on the energy gap (E0-0). The UV–vis and emission spectral studies revealed that dyes are absorbed in the region of λmax 485–577 nm and emitted at 567–673 nm. Their solvatochromic behavior in solvents of various polarities, CCl4, C6H6, H2O, CHCl3, acetone, and DMF, was studied to emphasize the effect of solvent polarity on the absorption maxima, molar extinction coefficients of the dyes, and excit

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22

Ester, David, Declan McKearney, Khrystyna Herasymchuk, and Vance Williams. "Heterocycle Effects on the Liquid Crystallinity of Terthiophene Analogues." Materials 12, no. 14 (2019): 2314. http://dx.doi.org/10.3390/ma12142314.

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Liquid crystalline self-assembly offers the potential to create highly ordered, uniformly aligned, and defect-free thin-film organic semiconductors. Analogues of one of the more promising classes of liquid crystal semiconductors, 5,5”-dialkyl-α-terthiophenes, were prepared in order to investigate the effects of replacing the central thiophene with either an oxadiazole or a thiadiazole ring. The phase behaviour was examined by differential scanning calorimetry, polarized optical microscopy, and variable temperature x-ray diffraction. While the oxadiazole derivative was not liquid crystalline, t

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23

Nivedita, Acharjee, Banerji Avijit, Jhawar Mira, and Barman Ambar. "Comparative DFT analysis of ELF topology and global properties of allyl and allenyl type three atom components (TACs)." Journal of Indian Chemical Society Vol. 97, May 2020 (2020): 753–59. https://doi.org/10.5281/zenodo.5654960.

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Department of Chemistry, Durgapur Government College, J. N. Avenue, Durgapur-713 214, West Bengal, India <em>E-mail</em>: nivchem@gmail.com Central Ayurveda Research Institute for Drug Development, CN Block, Sector V, Kolkata-700 091, India <em>Manuscript received online 09 December 2019, revised and accepted 09 January 2020</em> The term three atom components (TACs) is used in molecular electron density theory to denote three centre four electron π systems, which react with multiple bonded compounds to generate stereo- and regiochemically defined five membered heterocycles by [3+2] cycload

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24

Sayapin, Yury A., Inna O. Tupaeva, Alexandra A. Kolodina, et al. "2-Hetaryl-1,3-tropolones based on five-membered nitrogen heterocycles: synthesis, structure and properties." Beilstein Journal of Organic Chemistry 11 (November 12, 2015): 2179–88. http://dx.doi.org/10.3762/bjoc.11.236.

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A series of derivatives of 2-hetaryl-1,3-tropolone (β-tropolone) was prepared by the acid-catalyzed reaction of 2-methylbenzoxazoles, 2-methylbenzothiazoles and 2,3,3-trimethylindoline with 3,4,5,6-tetrachloro-1,2-benzoquinone. The molecular structures of the three representative compounds were determined by X-ray crystallography. In crystal and (as shown by the DFT PBE0/6-311+G** calculations) in solution, 2-hetaryl-4,5,6,7-tetrachloro- and 2-hetaryl-5,6,7-trichloro-1,3-tropolones exist in the NH-tautomeric form with a strong resonance-assisted intramolecular N–H···O hydrogen bond. The mechan

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25

Yang, Z. S., P. Y. Huang, J. J. Chen, et al. "Synthesis, crystal structure, and DFT study of 1-(2-bromobenzyl)- 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole." Журнал структурной химии 62, no. 6 (2021): 997–1006. http://dx.doi.org/10.26902/jsc_id72898.

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1-(2-Bromobenzyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole is an organic intermediate with both pyrazole heterocycle and borate functional group. In this paper, the title compound is obtained by the nucleophilic substitution reaction. The structure of the compound is confirmed by FTIR, 1H and 13C NMR spectroscopy, and MS. At the same time, the single crystal of the title compound is measured by X-ray diffraction and is subjected to the crystallographic and conformational analysis. The molecular structure is further calculated using density functional theory (DFT) and compare

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26

Dung, Tran Ngoc, Vu Chi Tuan, Nguyen Van Trang, Nguyen Minh Phuong, Pham Tho Hoan та Nguyen Thi Minh Hue. "Theoretical investigation of the effect of different π‐spacers on the performance of dye‐sensitized solar cells based on quinoline". Vietnam Journal of Chemistry 61, № 3 (2023): 294–99. http://dx.doi.org/10.1002/vjch.202100209.

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AbstractHerein we report a heterocyclic organic system to be used in dye‐sensitized solar cells. We propose 9 D‐π‐A compounds in with N,N‐diphenyl quinoline‐6‐amine as the electron donor, cyanoacrylic acid as the electron acceptor, and various conjugate systems of thiophene is used as a π‐spacers. The studied substance systems are calculated by density functional theory (DFT) method with 6‐311G(d) basis set. This study focuses on examining the effect of the π bridge on the properties of the molecule. The structural parameters of the molecular geometry were optimized, the HOMO and LUMO energies

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27

Mei, Zheng, Fengqi Zhao, Siyu Xu, and Xuehai Ju. "A simple relationship of bond dissociation energy and average charge separation to impact sensitivity for nitro explosives." Journal of the Serbian Chemical Society 84, no. 1 (2019): 27–40. http://dx.doi.org/10.2298/jsc180404059m.

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The bond dissociation energy (BDE) of the weakest bonds in 33 explosives were calculated and analyzed using the B3LYP method with the 6-311++G** basis set. A comparison between BDE and the impact sensitivity H50 showed that cleavage of the weakest bond plays an important role in the initiation of detonation. Using the generalized gradient approximation (GGA) with the Perdew?Burke?Ernzerhof (PBE) method and dispersion-corrected density functional theory (DFT-D), the simulation of compressed TNT (2-methyl-1,3,5- -trinitrobenzene) and royal demolition explosive (RDX, hexahydro- -1,3,5-trinitro-1,

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Hagar, Mohamed, Hoda A. Ahmed, Ghadah Aljohani, and Omaima A. Alhaddad. "Investigation of Some Antiviral N-Heterocycles as COVID 19 Drug: Molecular Docking and DFT Calculations." International Journal of Molecular Sciences 21, no. 11 (2020): 3922. http://dx.doi.org/10.3390/ijms21113922.

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The novel coronavirus, COVID-19, caused by SARS-CoV-2, is a global health pandemic that started in December 2019. The effective drug target among coronaviruses is the main protease Mpro, because of its essential role in processing the polyproteins that are translated from the viral RNA. In this study, the bioactivity of some selected heterocyclic drugs named Favipiravir (1), Amodiaquine (2), 2′-Fluoro-2′-deoxycytidine (3), and Ribavirin (4) was evaluated as inhibitors and nucleotide analogues for COVID-19 using computational modeling strategies. The density functional theory (DFT) calculations

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29

Zhu, Wei-Liang, Hua-Liang Jiang, Chum Mok Puah, et al. "Density functional theory (DFT) study on the interaction of ammonium (NH4+) and aromatic nitrogen heterocyclics." Journal of the Chemical Society, Perkin Transactions 2, no. 11 (1999): 2615–22. http://dx.doi.org/10.1039/a902663k.

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Deev, Sergey L., Alexander S. Paramonov, Tatyana S. Shestakova, et al. "15N-Labelling and structure determination of adamantylated azolo-azines in solution." Beilstein Journal of Organic Chemistry 13 (November 29, 2017): 2535–48. http://dx.doi.org/10.3762/bjoc.13.250.

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Determining the accurate chemical structures of synthesized compounds is essential for biomedical studies and computer-assisted drug design. The unequivocal determination of N-adamantylation or N-arylation site(s) in nitrogen-rich heterocycles, characterized by a low density of hydrogen atoms, using NMR methods at natural isotopic abundance is difficult. In these compounds, the heterocyclic moiety is covalently attached to the carbon atom of the substituent group that has no bound hydrogen atoms, and the connection between the two moieties of the compound cannot always be established via conve

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31

Zhang, Chenggen, Shuyuan Yu, Fei Wang, et al. "Insights into the Three-Component Coupling Reactions of Aldehydes, Alkynes, and Amines Catalyzed by N-heterocyclic Carbene Silver: A DFT Study." Catalysts 13, no. 4 (2023): 646. http://dx.doi.org/10.3390/catal13040646.

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Density functional theory (DFT) was used to investigate the three-component coupling reactions of aldehydes, alkynes, and amines (A3 coupling) using N-heterocyclic carbene silver as the catalyst. This study reveals that the addition reaction between the catalyst N-heterocyclic carbene silver and phenylacetylene (PAE) forms Ag_PAE. Subsequently, one hydrogen atom of the Ag_PAE migrates to the nitrogen atom of the Amine. Thereafter, the amine aldehyde condensation reaction generates a molecule of water and an imine ion with (Path one) or without (Path two) another amine catalyst. Path one has a

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32

Adda, Abdelghani, and Hayat Sediki. "Theoretical Study of the Aza˗Wittig Reaction, Me3P=NR (R = Methyl or Phenyl) with Aldehyde Using the DFT and DFT-D Methods (Dispersion Correction)." Chemistry Proceedings 3, no. 1 (2020): 47. http://dx.doi.org/10.3390/ecsoc-24-08349.

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: The Aza-Wittig reaction plays an important role in organic transformations and has seen considerable development in the construction of cyclic and acyclic compounds in neutral solvents in the absence of catalysts with a high yield of products. Today, the use of iminophosphoranes (phosphazenes) has become a powerful tool in organic synthesis strategies directed toward the construction of nitrogenous heterocycles. These can react with carbonyl compounds, an excellent method for the construction of C=N double bonds via intermolecular and intramolecular Aza-Wittig reactions. In this study, we ar

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Nagiparov, Kudaibergen, Sergey Beznosyuk, and Sergey Nikolskiy. "QUANTUM CHEMICAL STUDIES OF THE STRUCTURE AND THE PROTOLYTIC PROPERTIES OF SOME HETEROCYCLIC DERIVATIVES." Modern Technologies and Scientific and Technological Progress 2025, no. 1 (2025): 45–46. https://doi.org/10.36629/2686-9896-2025-1-45-46.

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Quantum-chemical calculations of the intermolecular proton transfer reaction from 3,6-di-tert-butyl-2-hydroxyphenoxyl to 1,4-diazabicyclo[2.2.2]octane (DABCO) in the gas phase were carried out. The density functional theory (DFT) method was used within the UB3LYP approximation with the 6-31+G(d,p) basis set. Analysis of the data allows us to obtain the energy characteristics of the studied system

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34

Memarian, Hamid R., Mahdieh Kalantari, and Hassan Sabzyan. "NMR and DFT Studies of 2-Oxo-1,2,3,4-tetrahydropyridines: Solvent and Temperature Effects." Australian Journal of Chemistry 71, no. 5 (2018): 380. http://dx.doi.org/10.1071/ch18018.

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Various 5-carboethoxy-2-oxo-1,2,3,4-tetrahydropyridines and their corresponding oxidation products containing methoxy or nitro groups on different positions of the C4-aryl ring were synthesized and the effect of steric and electrostatic interactions of these aryl substituents on the characteristic peaks in 1H NMR spectra were investigated. In addition, the intermolecular interaction of the parent compound and its oxidized form with solvent was experimentally investigated. For this, 1H NMR spectra of these compounds at different concentrations and temperatures in [D6]DMSO and CDCl3 were investi

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35

Morgon, Nelson H., Srijit Biswas, Surajit Duari, and Aguinaldo R. de Souza. "Solvent Effects in the Regioselective N-Functionalization of Tautomerizable Heterocycles Catalyzed by Methyl Trifluoromethanesulfonate: A Density Functional Theory Study with Implicit Solvent Model." Computation 10, no. 10 (2022): 172. http://dx.doi.org/10.3390/computation10100172.

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Methyl trifluoromethanesulfonate was found to catalyze the reaction of the nucleophilic substitution of the hydroxyl group of alcohols by N-heterocycles followed by X- to N- alkyl group migration (X = O, S) to obtain N-functionalized benzoxazolone, benzothiazolethione, indoline, benzoimidazolethione and pyridinone derivatives. A high degree of solvent dependency on the yield of the products was observed during optimization of the reaction parameters. The yield of the product was found to be 0%, 48% and 70% in acetonitrile, 1,2-dichloroethane and chloroform, respectively. The mechanism of the r

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36

Su, Biyun, Qiaoqiao Han, Xiaoteng Li, et al. "Synthesis, isomerization, and DFT studies of five-membered heterocyclic ketoximes." Journal of Chemical Research 45, no. 11-12 (2021): 1029–37. http://dx.doi.org/10.1177/17475198211032538.

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A homologous series of five-membered heterocyclic ketoximes is synthesized by condensation reactions of 2-acetylpyrrole, 2-acetylthiophene, and 2-acetylfuran with hydroxylamine hydrochloride. These compounds were fully characterized by X-ray single-crystal diffraction, elemental analysis, 1H NMR, IR, UV-Vis, and fluorescence spectra. Interesting isomerization phenomena are observed for these heterocyclic ketoximes by different characterization methods. By means of 1H NMR and X-ray single-crystal diffraction, it was found that 2-acetylpyrrole oxime (1) exists as the Z-type geometric isomer, 2-a

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37

Bahsis, Lahoucine, Meryem Hrimla, Hicham Ben El Ayouchia, Hafid Anane, Miguel Julve, and Salah-Eddine Stiriba. "2-Aminobenzothiazole-Containing Copper(II) Complex as Catalyst in Click Chemistry: An Experimental and Theoretical Study." Catalysts 10, no. 7 (2020): 776. http://dx.doi.org/10.3390/catal10070776.

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The reaction of copper(II) acetate with the 2-aminobenzothiazole (abt) heterocycle affords the new copper(II) complex of formula [Cu(abt)2(OOCCH3)2] (1) in a straightforward manner. Compound 1 served as a precatalyst for azide/alkyne cycloaddition reactions (CuAAC) in water, leading to 1,4-disubstituted-1,2,3-triazole derivatives in a regioselective manner and with excellent yields at room temperature. The main advantages of the coordination of such a heterocyclic ligand in 1 are its strong σ-donating ability (N-Cu), nontoxicity and biological properties. In addition, the click chemistry react

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38

Persoon, Emma, Yuekui Wang та Gerhard Raabe. "Quantum-Chemical Ab Initio Calculations on Inda- and Thallabenzene (C5H5In and C5H5Tl) and their Structural Isomers η5-C5H5In and η5-C5H5Tl". Australian Journal of Chemistry 71, № 3 (2018): 102. http://dx.doi.org/10.1071/ch17472.

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Quantum-chemical ab initio, time-independent, as well as time-dependent density functional theory (TD-DFT) calculations were performed on the so far elusive heterocycles inda- and thallabenzene (C5H5In and C5H5Tl), employing several different methods (MP2, CISD, CCSD, CCSD(T), BD, BD(T), QCISD, QCISD(T), CASSCF, DFT/B3LYP), effective core potentials, and different basis sets. While calculations on the MP2 level predict the ground states of the title compounds to be singlets with the first triplet states between 13 and 15 kcal mol−1 higher in energy, single point calculations with the QCISD(T),

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39

Egawa, Yasunobu, Chihiro Fukumoto, Koichiro Mikami, Nobuhiro Takeda, and Masafumi Unno. "Synthesis and Characterization of the Germathioacid Chloride Coordinated by an N-Heterocyclic Carbene §." Inorganics 6, no. 3 (2018): 76. http://dx.doi.org/10.3390/inorganics6030076.

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Carboxylic acid chlorides are useful substrates in organic chemistry. Many germanium analogues of carboxylic acid chloride have been synthesized so far. Nevertheless, all of the reported germathioacid chlorides use bidentate nitrogen ligands and contain germanium-nitrogen bonds. Our group synthesized germathioacid chloride, Ge(S)Cl{C6H3-2,6-Tip2}(Im-i-Pr2Me2), using N-heterocyclic carbene (Im-i-Pr2Me2). As a result of density functional theory (DFT) calculation, it was found that electrons are localized on sulfur, and the germanium-sulfur bond is a single bond with a slight double bond propert

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40

Luo, Qiuhan, Gang Li, Junping Xiao, et al. "DFT study on the hydrolysis of metsulfuron-methyl: A sulfonylurea herbicide." Journal of Theoretical and Computational Chemistry 17, no. 08 (2018): 1850050. http://dx.doi.org/10.1142/s0219633618500505.

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Sulfonylureas are an important group of herbicides widely used for a range of weeds and grasses control particularly in cereals. However, some of them tend to persist for years in environments. Hydrolysis is the primary pathway for their degradation. To understand the hydrolysis behavior of sulfonylurea herbicides, the hydrolysis mechanism of metsulfuron-methyl, a typical sulfonylurea, was investigated using density functional theory (DFT) at the B3LYP/6-31[Formula: see text]G(d,p) level. The hydrolysis of metsulfuron-methyl resembles nucleophilic substitution by a water molecule attacking the

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41

Fioroni, Marco, and Nathan J. DeYonker. "Siloxyl radical initiated HCN polymerization: computation of N-heterocycles formation and surface passivation." Monthly Notices of the Royal Astronomical Society 512, no. 2 (2022): 1629–38. http://dx.doi.org/10.1093/mnras/stac271.

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ABSTRACT In this work, by means of quantum chemistry (Density Functional Theory (DFT), PW6B95/def2-TZVPP; DLPNO-CCSD(T)/CBS), HCN polymerization [(HCN)1 − 4] initiated and catalysed by a siloxyl radical (Si-O•) on a model silica surface is analysed. Linear HCN polymers (pHCN) are obtained by a radical initiated mechanism at a SiO• site and are characterized by a -(HC-N)- skeleton due to radical localization on the terminal N atom and radical attack on the C centre. NC heterocycles are formed by cyclization of the linear SiO-(HCN)3 − 4 and are always thermodynamically preferred over their linea

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42

Zhu, Wei-Liang, Hua-Liang Jiang, Chum Mok Puah, et al. "ChemInform Abstract: Density Functional Theory (DFT) Study on the Interaction of Ammonium (NH4+) and Aromatic Nitrogen Heterocyclics." ChemInform 31, no. 7 (2010): no. http://dx.doi.org/10.1002/chin.200007037.

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43

Muppuli, M. V., K. Rajesh, A. R. Devaraj, et al. "Investigation of the Molecular Structure and DFT Insights into (4-(4-Nitrophenyl)-9-(phenylsulfonyl)-9H-carbazole-2,3-diyl)bis(p-tolylmethanone)." Журнал структурной химии 65, no. 5 (2024): 126947. http://dx.doi.org/10.26902/jsc_id126947.

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Carboxylate molecules have been distinguished as the potential compound in the largely emergent chemical world of heterocyclic compounds shows likely pharmacological characteristics. The knowledge of a mixture of synthetic pathways and the different physicochemical parameters of such compounds describe the especial interest of medicinal chemists to produce combinatorial collection and carry out in-depth efforts in the search of lead molecules. Among the various group of compounds studied, carboxylate moieties stand out to be unique in features due to their biological, pharmacological and medic

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44

Yu, Hao, Danielle L. Gray, Toby J. Woods, and Jeffrey S. Moore. "Trioxazolo[2³]metacyclophane: synthesis, structural analysis, and optical properties." Acta Crystallographica Section C Structural Chemistry 78, no. 2 (2022): 81–87. http://dx.doi.org/10.1107/s2053229622000298.

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The synthesis and characterization of the conjugated macrocycle trioxazolo[23]metacyclophane, C27H15N3O3 (M), is reported. The macrocycle was synthesized in three steps by the multicomponent van Leusen reaction and consists of meta-linked phenylenes connected through positions 4 and 5 of an oxazole heterocyclic ring. The molecular structure was investigated by NMR spectroscopy, mass spectrometry, gel permeation chromatography (GPC), and single-crystal X-ray crystallography. X-ray diffraction (XRD) analysis shows that M possesses a twisted saddle-like shape and interacts with nearby molecules b

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45

Morlacci, Valerio, Massimiliano Aschi, Marco Chiarini, Caterina Momoli, Laura Palombi, and Antonio Arcadi. "Product Selectivity Control in the Brønsted Acid-Mediated Reactions with 2-Alkynylanilines." Molecules 29, no. 15 (2024): 3693. http://dx.doi.org/10.3390/molecules29153693.

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Brønsted acid-catalysed/mediated reactions of the 2-alkynylanilines are reported. While metal-catalysed reactions of these valuable building blocks have led to the establishment of robust protocols for the selective, diverse-oriented syntheses of significant heterocyclic derivatives, we here demonstrate the practical advantages of an alternative methodology under metal-free conditions. Our investigation into the key factors influencing the product selectivity in Brønsted acid-catalysed/mediated reactions of 2-alkynylanilines reveals that different reaction pathways can be directed towards the

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46

Defant, Andrea, Nicole Innocenti, and Ines Mancini. "3a-(4-Chlorophenyl)-1-thioxo-2,3,3a,4-tetrahydroimidazo[1,5-a]quinazolin-5(1H)-one." Molbank 2024, no. 3 (2024): M1859. http://dx.doi.org/10.3390/m1859.

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With the aim of producing new heterocycle molecules, the previously reported 2-(aminomethyl)-2-(4-chlorophenyl)-2,3-dihydroquinazolin-4(1H)-one was converted efficiently by reacting with N,N′-dithiocarbonyldiimidazole (DTCI) to produce the substituted imidazolidine-2-thione moiety inserted in a three-fused-ring scaffold of the title compound. The molecular composition was confirmed by a high-resolution MS experiment, and its structure was elucidated by 1H, 13CNMR, and IR analyses. The thioacetamide form of the product was supported by density functional theory (DFT)–NMR analysis where 13C chem

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47

Neupane, Parrish, Neupane, et al. "Cytotoxic Sesquiterpenoid Quinones and Quinols, and an 11-Membered Heterocycle, Kauamide, from the Hawaiian Marine Sponge Dactylospongia elegans." Marine Drugs 17, no. 7 (2019): 423. http://dx.doi.org/10.3390/md17070423.

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Several known sesquiterpenoid quinones and quinols (1–9), and kauamide (10), a new polyketide-peptide containing an 11-membered heterocycle, were isolated from the extracts of the Hawaiian marine sponge Dactylospongia elegans. The planar structure of 10 was determined from spectroscopic analyses, and its relative and absolute configurations were established from density functional theory (DFT) calculations of the GIAO NMR shielding tensors, and advanced Marfey’s analysis of the N-MeLeu residue, respectively. Compounds 1 and 3 showed moderate inhibition of β-secretase 1 (BACE1), whereas 1–9 exh

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48

Çakmak, Şükriye, Başak Koşar Kırca, Aysel Veyisoğlu, Hasan Yakan, Cem Cüneyt Ersanlı, and Halil Kütük. "Experimental and theoretical investigations on a furan-2-carboxamide-bearing thiazole: synthesis, molecular characterization by IR/NMR/XRD, electronic characterization by DFT, Hirshfeld surface analysis and biological activity." Acta Crystallographica Section C Structural Chemistry 78, no. 3 (2022): 201–11. http://dx.doi.org/10.1107/s2053229622002066.

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A thiazole-based heterocyclic amide, namely, N-(thiazol-2-yl)furan-2-carboxamide, C8H6N2O2S, was synthesized and investigated for its antimicrobial activity. The structure was characterized by elemental analysis and IR, 1H NMR, and 13C NMR spectroscopy. The molecular and electronic structures were investigated experimentally by single-crystal X-ray diffraction (XRD) and theoretically by density functional theory (DFT) modelling. The compound crystallized in the monoclinic space group P21/n and the asymmetric unit contains two symmetrically independent molecules. Several noncovalent interaction

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Georgiou, Nikitas, Danai Karta, Antigoni Cheilari, et al. "Synthesis of Thiazolidin-4-Ones Derivatives, Evaluation of Conformation in Solution, Theoretical Isomerization Reaction Paths and Discovery of Potential Biological Targets." Molecules 29, no. 11 (2024): 2458. http://dx.doi.org/10.3390/molecules29112458.

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Thiazolin-4-ones and their derivatives represent important heterocyclic scaffolds with various applications in medicinal chemistry. For that reason, the synthesis of two 5-substituted thiazolidin-4-one derivatives was performed. Their structure assignment was conducted by NMR experiments (2D-COSY, 2D-NOESY, 2D-HSQC and 2D-HMBC) and conformational analysis was conducted through Density Functional Theory calculations and 2D-NOESY. Conformational analysis showed that these two molecules adopt exo conformation. Their global minimum structures have two double bonds (C=N, C=C) in Z conformation and

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50

Abdelrehim, El-sayed M., and Doaa S. El-Sayed. "A New Synthesis of Poly Heterocyclic Compounds Containing [1,2,4]triazolo and [1,2,3,4]tetrazolo Moieties and their DFT Study as Expected Anti-cancer Reagents." Current Organic Synthesis 17, no. 3 (2020): 211–23. http://dx.doi.org/10.2174/1570179417666200226092516.

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Background: 2-amino-3-cyanopyridines are good starting reagents that have been used in synthesis of many heterocyclic compounds such as pyridopyrimidines, [1,2,4]triazolo and [1,2,3,4] tetrazolo derivatives which have biological activities as anti-microbial and cytotoxic activities. Meanwhile [1,2,4]triazolo and [1,2,3,4]tetrazolo derivatives are well known to possess many physiological activities, such as anticancer , antifungal, muscle relaxant, hypnotic, anti-inflammatory, diuretic and antihypertensive activities. A broad class of heterocyclic compounds has been studied to demonstrate their

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