Results 71 to 80 of about 5,976 (269)

Aromaticity and Antiaromaticity: How to Define Them

Chemistry
Aromaticity and antiaromaticity are concepts that are often used to explain and predict the physical and chemical properties of cyclic conjugated compounds.
Marija Baranac-Stojanović
doaj   +1 more source

Synthesis of 3,4-Bis(benzylidene)cyclobutenes [PDF]

, 2011
The syntheses of several derivatives of 3,4-bis(benzylidene)cyclobutene are reported. Previously unknown 1,2-dibromo-3,4-bis(benzylidene)cyclobutene was obtained through in situ generation of 1,6-diphenyl-3,4-dibromo-1,2,4,5-tetraene followed by ...
Parkhurst, Rebecca Rosenberg, Swager, Timothy Manning   +1 more
core   +1 more source

Identification and quantification of local antiaromaticity in polycyclic aromatic hydrocarbons (PAHs) based on the magnetic criterion.

Organic and biomolecular chemistry
The spatial magnetic properties, through-space NMR shieldings (TSNMRSs, actually the ring current effect in 1H NMR spectroscopy), of a selection of entirely antiaromatic and aromatic polycyclic conjugated hydrocarbons (PCHs), and aromatic PCHs with ...
E. Kleinpeter, A. Koch
semanticscholar   +1 more source

Evaluation of the aromatic character of some bowl shape polycyclic carbon nanostructures [PDF]

شیمی کاربردی روز, 2017
In two recent decades, nucleus independent chemical shift (NICS) criterion was used to gauge the amount of aromaticity of organic and inorganic compounds in a lot of publications.
Adel Reisi-Vanani, fatemeh hajizadeh
doaj   +1 more source

A QCT View of the Interplay between Hydrogen Bonds and Aromaticity in Small CHON Derivatives

Molecules, 2022
The somewhat elusive concept of aromaticity plays an undeniable role in the chemical narrative, often being considered the principal cause of the unusual properties and stability exhibited by certain π skeletons. More recently, the concept of aromaticity
Miguel Gallegos, Daniel Barrena-Espés, José Manuel Guevara-Vela, Tomás Rocha-Rinza, Ángel Martín Pendás   +4 more
doaj   +1 more source

The homotropenylium cation : a system with a pinched π ring current [PDF]

, 2014
The homotropenylium cation (1, C8H9+) is a key species in the discussion of homoaromaticity. Constrained optimisations around the minimum structure have been performed, varying the size of the gap spanned by the CH2-bridge and optimising all other ...
Baker, Jon, Fowler, Patrick W, Havenith, Remco, Jenneskens, Leonardus W, Lillington, Mark   +4 more
core   +3 more sources

Contemplation on some cyclic N8 isomers-A DFT treatment

Defence Technology, 2018
Various cyclic N8 isomers are considered at the levels of B3LYP/6–311++G(d,p) and B3LYP/cPVTZ. Some energies and molecular orbital properties are obtained. The structures are found to be stable in the singlet state but mostly unstable in the triplet. The
Lemi Türker
doaj   +1 more source

20π antiaromatic isophlorins without metallation or core modification [PDF]

, 2022
Haruna Sugimura, Kana Nakajima, K. Yamashita, Takuji Ogawa   +3 more
openalex   +1 more source

Probing Effects of Electron Addition to Polycyclic Conjugated Hydrocarbons Containing Four‐Membered Rings

ChemistryEurope
The rectangular cyclobutadiene (CBD, C4H4) is a unique moiety for building nonbenzenoid polycyclic conjugated hydrocarbons with interesting electron‐accepting properties.
Yikun Zhu, Ke Zheng, Zheng Wei, Yan Xia, Marina A. Petrukhina   +4 more
doaj   +1 more source

Rücktitelbild: Electronic Materials: An Antiaromatic Propeller Made from the Four‐Fold Fusion of Tetraoxa[8]circulene and Perylene Diimides (Angew. Chem. 48/2022) [PDF]

, 2022
Viktor Bliksted Roug Pedersen, Stephan K. Pedersen, Zexin Jin, Nicolaj Kofod, Bo W. Laursen, Glib Baryshnikov, Colin Nuckolls, Michael Pittelkow   +7 more
openalex   +1 more source