نتایج جستجو برای: aromaticity

تعداد نتایج: 1178  

Journal: :Chemical communications 2012
Hideaki Miyake Takahiro Sasamori Judy I-Chia Wu Paul v R Schleyer Norihiro Tokitoh

Reduction of a 4,5,6-triphospha[3]radialene gave the corresponding isolable dianionic species. Despite having two deltate dianion-like π-electrons delocalized over the central framework, its small NICS(0)(πzz) value (only -2.2 ppm) indicates only limited aromaticity.

Journal: :Bulletin of the Chemical Society of Japan 1978

Journal: :Environmental science & technology 2009
Benny Chefetz Baoshan Xing

The sorption behavior of hydrophobic organic compounds (HOCs) in the environment has been the focus of numerous studies. In most of them, the role of aliphatic domains in sorption has been ignored, even although aliphatic components make up a significant portion of the soil organic matter (SOM). The objective of this review is to elucidate the role of the molecular descriptors--aromaticity and ...

Journal: :Organic & biomolecular chemistry 2010
Claire Seillan Philippe Marsal Olivier Siri

A new and efficient one-pot synthesis of highly stable bridged-bisphenazine-type molecules with loss of their aromaticity in the ground state in favor of a quinoid-type structure is described (either in solution or in solid-state).

Journal: :Chemical communications 2014
Raphael J F Berger Matthew J Fuchter Ingo Krossing Henry S Rzepa Julia Schaefer Harald Scherer

The facile gold-mediated skeletal rearrangement of [7]-helicene into a cationic polyaromatic hydrocarbon is described. We report in-depth studies on the structure and aromaticity of this novel stable cation and propose a mechanism for its formation.

In the 1- (4-fluorophenyl) -2,3-dihydro-1 H-naphto- [1 and 2-e] [1 and 3] oxazine-3-n, there are 4 rings, respectively, rings from the side attached to the halogen They are named C, B, A, and D. Calculations and studies show that the amount of aromatics in the halogen-ring A in all cases has the highest number. In the B loop, the predicted aromatism level is zero, and in the ring C and D, relat...

Journal: :Dalton transactions 2010
Ashwini K Phukan Ankur Kanti Guha Bernard Silvi

A combined DFT, AIM and ELF study has been carried out on borazine and its heavier analogs containing both the pnictogens and chalcogens as the ring constituent. Compared to the pnictogen substituted rings, chalcogen substituted rings are found to be less aromatic. Except for a few systems, the computed aromatic stabilization energies (ASE) do not correlate with the NICS values. For these ring ...

Journal: :Chemistry 2007
Marcin Palusiak Tadeusz M Krygowski

The AIM parameters at the ring critical point (the electron density and its Laplacian, the total electron energy density and both its components, potential and kinetic electron energy densities), have been intercorrelated with aromaticity indices: the geometry-based HOMA and the magnetism-based NICS, NICS(1), and NICS(1)(zz). A set of 33 phenylic rings having possibly a diversified aromatic cha...

2017
Shintaro Fujii Santiago Marqués-González Ji-Young Shin Hiroshi Shinokubo Takuya Masuda Tomoaki Nishino Narendra P Arasu Héctor Vázquez Manabu Kiguchi

Aromaticity is a fundamental concept in chemistry. It is described by Hückel's rule that states that a cyclic planar π-system is aromatic when it shares 4n+2 π-electrons and antiaromatic when it possesses 4n π-electrons. Antiaromatic compounds are predicted to exhibit remarkable charge transport properties and high redox activities. However, it has so far only been possible to measure compounds...

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