نتایج جستجو برای: aromaticity and rahb

تعداد نتایج: 16827345  

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: :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...

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 ...

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...

2015
Juan J Torres-Vega Alejandro Vásquez-Espinal Lina Ruiz María A Fernández-Herrera Luis Alvarez-Thon Gabriel Merino William Tiznado

The electron delocalization of benzene (C6H6) and hexafluorobenzene (C6F6) was analyzed in terms of the induced magnetic field, nucleus-independent chemical shift (NICS), and ring current strength (RCS). The computed out-of-plane component of the induced magnetic field at a distance (r) greater than or equal to 1.0 Å above the ring center correlates well (R (2)>0.99) with the RCS value. Accordi...

2005
Anastassia N. Alexandrova Alexander I. Boldyrev Hua-Jin Zhai Lai-Sheng Wang

Small boron clusters as individual species in the gas phase are reviewed. While the family of known boron compounds is rich and diverse, a large body of hitherto unknown chemistry of boron has been recently identified. Free boron clusters have been recently characterized using photoelectron spectroscopy and ab initio calculations, which have established the planar or quasi-planar shapes of smal...

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