Cyclisierungsversuche an O‐[Aryloxy‐carbimidoyl]‐amidoximen

Schmidt, Reinhard H.; Westphal, G.; Frölich, Barbara

doi:10.1002/zfch.19740140708

Cited by 10 publications

(7 citation statements)

References 9 publications

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“…The choice of 1.9 Å is arbitrary and we have provided an animation (PiBandDensity_mov.mp4) in the Supporting Information that shows variations in the π ‐electron distribution for multiple slices across the a‐CNT 400 model discussed here. The cross‐interaction of the quasi‐free π ‐electrons in the gallery posses weak metallic bonding between the tubes, [ 73 ] and this contributes to the cohesion between the layers. [ 23,24,74,75 ]…”

Section: Resultsmentioning

confidence: 99%

“…The choice of 1.9 Å is arbitrary and we have provided an animation (PiBandDensity_mov.mp4) in the Supporting Information that shows variations in the π-electron distribution for multiple slices across the a-CNT 400 model discussed here. The cross-interaction of the quasi-free π-electrons in the gallery posses weak metallic bonding between the tubes, [73] and this contributes to the cohesion between the layers. [23,24,74,75] In a-CNT, the maximum value for the π-electron density is %10% of the maximum total charge distribution in all the bands, and it is also % 2.75% of the maximum total charge distribution around the center of the gallery.…”

Section: Electronic Structure Transport and π-Electron Delocalizationmentioning

confidence: 99%

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Formation of Amorphous Carbon Multi‐Walled Nanotubes from Random Initial Configurations

Ugwumadu

Thapa

Al-Majali

et al. 2023

Physica Status Solidi (b)

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Amorphous carbon nanotubes (a‐CNT) with up to four walls and sizes ranging from 200 to 3200 atoms have been simulated, starting from initial random configurations and using the Gaussian Approximation Potential. The important variables (like density, height, and diameter) required to successfully simulate a‐CNTs were predicted with the machine learning random forest technique. The width of the a‐CNT models ranged between 0.55–2 nm with an average inter‐wall spacing of 0.31 nm. The topological defects in a‐CNTs were analyzed and new defect configurations were observed. The electronic density of states and localization in these phases were discussed and delocalized electrons in the π subspace were identified as an important factor for inter‐layer cohesion. Spatial projection of the electronic conductivity favors axial transport along connecting hexagons, while non‐hexagonal parts of the network either hinder or bifurcate the electronic transport. A vibrational density of states was calculated and is potentially an experimentally comparable fingerprint of the material. The appearance of a low‐frequency radial breathing mode was discussed and the thermal conductivity at 300 K was estimated using the Green‐Kubo formula.

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Section: Resultsmentioning

confidence: 99%

Section: Electronic Structure Transport and π-Electron Delocalizationmentioning

confidence: 99%

Formation of Amorphous Carbon Multi‐Walled Nanotubes from Random Initial Configurations

Ugwumadu

Thapa

Al-Majali

et al. 2023

Physica Status Solidi (b)

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“…The first investigation goes back to 1930s with the pioneer work of Cook et al,21, 22 who tried to correlate the CA with some geometrical features of the molecule. However, Schmidt23 was the first to draw attention to the importance of the electronic features in determining the biological properties of PAHs. Accordingly, PAHs having high electron density regions are considered to be strong carcinogens.…”

Section: Introductionmentioning

confidence: 99%

Theoretical studies on the carcinogenicity of polycyclic aromatic hydrocarbons

Vijayalakshmi

Suresh

2008

J Comput Chem

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The distinct molecular regions of a set of 28 polycyclic aromatic hydrocarbons (PAHs) showing varying degrees of carcinogenic activity (CA) have been analyzed on the basis of their calculated molecular electrostatic potential (MESP) at B3LYP/6-31+G(d,p) level of theory. The MESP, being a property directly related to electron density, clearly distinguishes the electron dense centers in the molecule into K, L, M, and newly defined N regions. Further, a quantitative structure activity relationship (QSAR) model of carcinogenicity is developed using the volume of MESP lobes at the named regions for a set of 17 carcinogenic molecules with experimentally known CA index. The QSAR equation suggested that all the geometrical regions are significant in determining the carcinogenic property of PAHs. The model clearly showed that K and M regions have activating carcinogenic effect whereas L and N regions have deactivating carcinogenic effect. The CA showed considerable enhancement when any three distinct regions are present in a PAH. On the other hand, all the PAH systems with only one type of region are inactive irrespective of whether the region is activating or deactivating. Similarly, molecules showing the presence of two types of regions are either inactive or weakly active. The essential features of both the "K, L region" and the "bay region" theories of carcinogenesis are well evident in the new QSAR model, as the former theory works on the basis of activating K and deactivating L regions whereas the latter theory is related with the activating M region.

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“…We have taken cues from an alternative approach that was suggested by Pauling [13] and applied by many researchers [14][15][16][17][18][19][20][21] on the conjugated hydrocarbons utilizing the free electron model for the delocalized π electrons of conjugated systems. Comprehensive treatments of a large number of representative organic molecules using the two alternative techniques of LCAO molecular orbitals and the free electron model [22][23][24] found considerable agreement between the two approaches.…”

Section: Introductionmentioning

confidence: 99%

“…Comprehensive treatments of a large number of representative organic molecules using the two alternative techniques of LCAO molecular orbitals and the free electron model [22][23][24] found considerable agreement between the two approaches. Therefore, treatment of the π electrons in conjugated systems as a Fermi electron gas is not new and has been successfully attempted before [13][14][15][16][17][18][19][20][21][22][23][24]. As this alternative approach did not provide any breakthroughs in determining the chemical properties of the planar, conjugated, saturated as well as unsaturated hydrocarbons, it has not been the preferred tool of the chemist.…”

Section: Introductionmentioning

confidence: 99%

The degenerate Fermi gas of π electrons in fullerenes and the σ surface instabilities

Ahmad¹,

Khan²,

Manzoor³

2006

Nanotechnology

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The departure from perfect spherical symmetry in the case of fullerenes (C60 being the sole exception) induces instabilities due to the stresses generated by the pentagonal protrusions in the σ-bonded surfaces. By assuming σ-π separability and treating π electrons as a degenerate Fermi gas in the two shells around the central σ structure, the resulting degeneracy pressures can further enhance the σ-surface initiated instabilities for non-icosahedral structures (especially for those C60) with large protrusions. Under certain circumstances the net degeneracy pressure across the σ surface may have a structure stabilizing effect. The role of the π-electron degeneracy in a broad range of fullerenes from C20 to C1500 and its effects on fullerene stability are investigated.

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Cyclisierungsversuche an O‐[Aryloxy‐carbimidoyl]‐amidoximen

Cited by 10 publications

References 9 publications

Formation of Amorphous Carbon Multi‐Walled Nanotubes from Random Initial Configurations

Formation of Amorphous Carbon Multi‐Walled Nanotubes from Random Initial Configurations

Theoretical studies on the carcinogenicity of polycyclic aromatic hydrocarbons

The degenerate Fermi gas of π electrons in fullerenes and the σ surface instabilities

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