Hybrid density functional theory investigation of a series of alloxan-based thiosemicarbazones and semicarbazones

AbstractRecently, the synthesis and the NMR characterization of a series of eight alloxan-based thiosemicarbazones and semicarbazones were reported. These compounds exhibit a strongly hydrogenbonded hydrazinic proton that is a part of a characteristic six-membered ring. This proton is highly deshielded and resonates far downfield in the proton NMR spectra. In this report, mPW1PW91/6-31+G(d,p) calculations have been used to investigate the structure and other molecular properties of this series of eight compounds. The relationship between the 1H and 13C NMR chemical shifts and various geometric parameters was investigated, and linear relationships for proton peaks that are involved in hydrogen-bond interactions were found.

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A theoretical investigation on the isomerism and the NMR properties of thiosemicarbazones

Open Chemistry ◽

10.2478/s11532-007-0012-1 ◽

2007 ◽

Vol 5 (2) ◽

pp. 396-419 ◽

Cited By ~ 3

Author(s):

N. Nuwan De Silva ◽

Titus Albu

Keyword(s):

Density Functional ◽

Chemical Shifts ◽

Intermolecular Hydrogen Bond ◽

Density Functional Theory Calculations ◽

Functional Theory ◽

1H And 13C Nmr ◽

Nmr Characterization ◽

Hybrid Density Functional ◽

Nmr Properties

AbstractHybrid density functional theory calculations at the mPW1PW91/6-31+G(d,p) level of theory have been used to investigate the optimized structures and other molecular properties of five different series of thiosemicarbazones. The investigated compounds were obtained from acenaphthenequinone, isatin and its derivatives, and alloxan. The focus of the study is the isomerism and the NMR characterization of these thiosemicarbazones. It was found that only one isomer is expected for thiosemicarbazones and methylthiosemicarbazones, while for dimethylthiosemicarbazones, two isomers are possible. All investigated thiosemicarbazones exhibit a hydrazinic proton that is highly deshielded and resonates far downfield in the proton NMR spectra. This proton is a part of a characteristic sixmembered ring, and its NMR properties are a result of its strong, intermolecular hydrogen bond. The relationships between the calculated 1H and 13C NMR chemical shifts and various geometric parameters are reported.

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Structural and spectroscopic characterization and DFT studies of 2-amino-1,10-phenanthrolin-1-ium chloride

European Journal of Chemistry ◽

10.5155/eurjchem.10.2.95-101.1847 ◽

2019 ◽

Vol 10 (2) ◽

pp. 95-101

Author(s):

Sebile Işık Büyükekşi ◽

Namık Özdemir ◽

Abdurrahman Şengül

Keyword(s):

Density Functional Theory ◽

Electronic Absorption ◽

13C Nmr ◽

Density Functional ◽

Electronic Absorption Spectra ◽

Chemical Shifts ◽

Atomic Orbital ◽

Basis Set ◽

Functional Theory ◽

1H And 13C Nmr

A versatile synthetic building block, 2-amino-1,10-phenanthrolin-1-ium chloride (L∙HCl) was synthesized and characterized by IR, 1H and 13C NMR DEPT analysis, UV/Vis and single-crystal X-ray diffraction technique. The molecular geometry, vibrational wavenumbers and gauge including atomic orbital (GIAO), 1H and 13C NMR chemical shifts values of the title compound in the ground state were obtained by using density functional theory (DFT/B3LYP) method with 6-311++G(d,p) basis set and compared with the experimental data. Electronic absorption spectrum of the salt was determined using the time-dependent density functional theory (TD-DFT) method at the same level. In the NMR and electronic absorption spectra calculations, the effect of solvent on the theoretical parameters was included using the default model with DMSO as solvent. The obtained theoretical parameters agree well with the experimental findings.

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Computational Study of Tetrahedral Fullerenes Containing Fused Pentagon-Triples

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2021.18972 ◽

2021 ◽

Vol 21 (4) ◽

pp. 2419-2426

Author(s):

Csaba L. Nagy ◽

Katalin Nagy

Keyword(s):

Density Functional ◽

Computational Study ◽

Chemical Shifts ◽

Point Group ◽

Functional Theory ◽

Global Strain ◽

The Stability ◽

Global And Local ◽

Hybrid Density Functional ◽

Electronic And Structural Properties

Fullerenes that violate the isolated pentagon rule are too reactive and were obtained only as endoor exohedral derivatives. Density functional theory using the B3LYP hybrid density functional was applied to investigate the electronic and structural properties of the ten smallest tetrahedral (Td or T point group) fullerenes containing four directly fused pentagon-triples. The influence of nitrogen doping and exohedral hydrogenation of the four reactive sites was also analyzed. Nucleus independent chemical shifts values computed using B3LYP/6-31G(d) are used as global and local aromaticity probe. The global strain energy is evaluated in terms of the pyramidalization (POAV) angle. The results show that the stability increases with the elimination of the energetically unfavorable strain.

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NMR spectroscopy of the phenyl derivative of germanium(IV) 5,10,15-tritolylcorrole

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424616500450 ◽

2016 ◽

Vol 20 (01n04) ◽

pp. 525-533

Author(s):

Giampaolo Ricciardi ◽

Daniel O. Cicero ◽

Sara Lentini ◽

Sara Nardis ◽

Roberto Paolesse ◽

...

Keyword(s):

Density Functional ◽

Chemical Shifts ◽

2D Nmr ◽

Functional Theory ◽

Phenyl Derivative ◽

Shielding Constants ◽

Shielding Tensor ◽

Experimental Values ◽

Molecular And Electronic Structure

A thoroughly structural characterization of (TTC)GePh (TTC [Formula: see text] 5,10,15-tritolylcorrole; Ph [Formula: see text] phenyl) in solution has been carried out through a combination of 2D NMR (1H-1H COSY, 1H-1H ROESY, 1H-[Formula: see text]C HSQC and 1H-[Formula: see text]C HMBC) experiments and density functional theory (DFT) calculations of the molecular and electronic structure and the shielding constants. The 1H and [Formula: see text]C chemical shifts computed at DFT-S12g and DFT-SAOP levels of theory nicely reproduce the experimental values, the agreement between theory and experiment being especially good for the DFT-S12g results. The calculations prove to be able to capture the fine details of the NMR spectra and to resolve some assignment ambiguities related to the inherent conformational flexibility of the macrocycle. The calculations also provide an explanation of the observed chemical shift trends in terms of diamagnetic and paramagnetic components of the shielding tensor.

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Spectroscopic (FT-IR,1H and 13C NMR) characterization and density functional theory calculations for (Z)-5-(4-nitrobenzyliden)-3-N(2-ethoxyphenyl)-2-thioxo-thiazolidin-4-one (ARNO)

Journal of Molecular Structure ◽

10.1016/j.molstruc.2017.06.102 ◽

2017 ◽

Vol 1147 ◽

pp. 569-581 ◽

Cited By ~ 7

Author(s):

K. Toubal ◽

N. Boukabcha ◽

Ö. Tamer ◽

N. Benhalima ◽

S. Altürk ◽

...

Keyword(s):

Density Functional Theory ◽

13C Nmr ◽

Density Functional ◽

Density Functional Theory Calculations ◽

Functional Theory ◽

1H And 13C Nmr ◽

Nmr Characterization ◽

Ft Ir

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Structural characterization of kaempferol: a spectroscopic and computational study

Macedonian Journal of Chemistry and Chemical Engineering ◽

10.20450/mjcce.2019.1333 ◽

2019 ◽

Vol 38 (1) ◽

pp. 49 ◽

Cited By ~ 2

Author(s):

Dejan Milenković ◽

Jasmina M Dimitrić Marković ◽

Dušan Dimić ◽

Svetlana Jeremić ◽

Dragan Amić ◽

...

Keyword(s):

Density Functional ◽

Computational Study ◽

Chemical Shifts ◽

Absolute Error ◽

Nbo Analysis ◽

Basis Set ◽

Functional Theory ◽

The Density Functional Theory ◽

Spectroscopic Characteristics

Calculations based on the density functional theory, with the B3LYP functional and the 6-311++G(d,p) basis set, were performed with the aim of confirming the molecular structure and spectroscopic characteristics of kaempferol, a naturally occurring flavonoid molecule. The electronic structure of kaempferol was examined using NBO analysis. The assigning of the experimentally obtained IR and Raman spectra was performed after the best-fit-based comparison with theoretical spectra. The 13C and 1H NMR experimental spectra were related to the theoretically obtained values of the chemical shifts determined by the GIAO method. The correlation coefficient and the average absolute error values proved B3LYP-D3 to be an adequate method in describing the NMR parameters of kaempferol. Molecular docking analysis was carried out in order to identify the potency of inhibition of the title molecule against human procalcitonin. The inhibition activity was obtained for 10 conformations of ligand inside the protein.

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Substituent Effects on NMR Spectroscopy of 2,2-Dimethylchroman-4-one Derivatives: Experimental and Theoretical Studies

Molecules ◽

10.3390/molecules25092061 ◽

2020 ◽

Vol 25 (9) ◽

pp. 2061

Author(s):

Daniela Iguchi ◽

Davide Ravelli ◽

Rosa Erra-Balsells ◽

Sergio M. Bonesi

Keyword(s):

Density Functional ◽

Chemical Shifts ◽

Substituent Effects ◽

Heterocyclic Ring ◽

Functional Theory ◽

1H And 13C Nmr ◽

Meta Position ◽

Experimental And Theoretical Studies ◽

Nmr Signals ◽

C Nmr

The attribution of 1H and 13C NMR signals of a library of 5-, 6- and 7-substituted 2,2-dimethylchroman-4-one derivatives is reported. Substituent effects were interpreted in terms of the Hammett equation, showing a good correlation for carbons para- to the substituent group, not for the meta- ones. Similarly, the Lynch correlation shows the additivity of the substituent chemical shifts in the case of both H and C nuclei, again with the exception of the carbons in the meta- position. Density Functional Theory (DFT)-predicted 1H and 13C chemical shifts correspond closely with experimentally observed values, with some exceptions for C NMR data; however, the correlation is valid only for the aromatic moiety and cannot be extended to the heterocyclic ring of the chroman-4-one scaffold.

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Density functional theory: 1H and 13C-NMR spectra of some coumarin derivatives

Journal of the Serbian Chemical Society ◽

10.2298/jsc140221023s ◽

2014 ◽

Vol 79 (11) ◽

pp. 1405-1411 ◽

Cited By ~ 3

Author(s):

Selma Spirtovic-Halilovic ◽

Mirsada Salihovic ◽

Snezana Trifunovic ◽

Suncica Roca ◽

Elma Veljovic ◽

...

Keyword(s):

Density Functional Theory ◽

13C Nmr ◽

Density Functional ◽

Nmr Spectra ◽

Chemical Shifts ◽

13C Nmr Spectra ◽

Coumarin Derivatives ◽

Functional Theory ◽

1H And 13C Nmr ◽

Isotropic Chemical Shifts

For some synthesized coumarin derivatives, 1H and 13C NMR isotropic chemical shifts and some other molecular properties were calculated using density functional theory. The calculations yield reliable results, that are in good correlation with experimental data. This is a good basis for the collaboration between experimentalists and quantum chemists.

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