نتایج جستجو برای: electron delocalization

تعداد نتایج: 310383  

Journal: :Angewandte Chemie International Edition 2016

2010
Ewa D. Raczyñska Małgorzata Hallman Katarzyna Kolczyñska

The HOMA (Harmonic Oscillator Model of Aromaticity) index, reformulated in 1993, has been very often applied to describe π-electron delocalization for monoand polycyclic π-electron systems. However, different measures of π-electron delocalization were employed for the CC, CX, and XY bonds, and this index seems to be inappropriate for compounds containing heteroatoms. In order to describe proper...

Journal: :Symmetry 2010
Ewa D. Raczynska Malgorzata Hallman Katarzyna Kolczynska Tomasz M. Stepniewski

The HOMA (Harmonic Oscillator Model of Aromaticity) index, reformulated in 1993, has been very often applied to describe π-electron delocalization for monoand polycyclic π-electron systems. However, different measures of π-electron delocalization were employed for the CC, CX, and XY bonds, and this index seems to be inappropriate for compounds containing heteroatoms. In order to describe proper...

Journal: :Physical chemistry chemical physics : PCCP 2015
Benjamin G Janesko Giovanni Scalmani Michael J Frisch

Delocalized, solvated electrons are a topic of much recent interest. We apply the electron delocalization range EDR(r;u) (J. Chem. Phys., 2014, 141, 144104) to quantify the extent to which a solvated electron at point r in a calculated wavefunction delocalizes over distance u. Calculations on electrons in one-dimensional model cavities illustrate fundamental properties of the EDR. Mean-field ca...

Journal: :international journal of bio-inorganic hybrid nanomaterials 0

in this study, the adsorption of 4-hydroxy phenyl-azobenzene on the surface of (4, 0) zigzag open-end boron nitride nanotube (bnnt) has been investigated by quantum calculations. in order to find the preferred adsorption site, different positions and orientations were considered. the impacts of donor-acceptor electron delocalization on the structural and electronic properties and reactivity of ...

2014
Amit Choudhary Robert W. Newberry Ronald T. Raines

An n→π* interaction stems from the delocalization of the electron pair (n) of a donor group into the antibonding orbital (π*) of a carbonyl group. Crystallographic analyses of five pairs of diastereoisomers demonstrate that an n→π* interaction can induce chirality in an otherwise planar, prochiral carbonyl group. Thus, a subtle delocalization of electrons can have stereochemical consequences.

Journal: :Physical chemistry chemical physics : PCCP 2016
Claudia E Tait Patrik Neuhaus Martin D Peeks Harry L Anderson Christiane R Timmel

The optoelectronic properties of conjugated porphyrin arrays render them excellent candidates for use in a variety of molecular electronic devices. Understanding the factors controlling the electron delocalization in these systems is important for further developments in this field. Here, we use transient EPR and ENDOR (Electron Nuclear Double Resonance) to study the extent of electronic deloca...

Journal: :Chemical communications 2013
Amit Choudhary Charles G Fry Kimberli J Kamer Ronald T Raines

Carbonyl-carbonyl (C=O···C'=O') interactions are ubiquitous in both small and large molecular systems. This interaction involves delocalization of a lone pair (n) of a donor oxygen into the antibonding orbital (π*) of an acceptor carbonyl group. Analyses of high-resolution protein structures suggest that these carbonyl-carbonyl interactions prefer to occur in pairs, that is, one donor per accep...

Journal: :The journal of physical chemistry. A 2008
Ferran Feixas Eduard Matito Miquel Solà Jordi Poater

In the present work, we analyze the pi-electronic delocalization in a series of annulenes and their dications and dianions by using electron delocalization indices calculated in the framework of the quantum theory of atoms in molecules. The aim of our study is to discuss the Hückel's 4n + 2 rule from the viewpoint of pi-electronic delocalization. Our results show that there is an important incr...

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