نتایج جستجو برای: π electron delocalization

تعداد نتایج: 340883  

1999
Niels H. Damrauer James K. McCusker

The transition metal complexes [Ru(dmb)3] and [Ru(dpb)3], where dmb is 4,4′-dimethyl-2,2′-bipyridine and dpb is 4,4′-diphenyl-2,2′-bipyridine, have been studied by femtosecond visible electronic absorption spectroscopy. Spectroelectrochemical measurements in conjunction with nanosecond time-resolved absorption spectroscopy allow for the assignment of various features in the excited-state differ...

2011
Amit Choudhary Kimberli J. Kamer Ronald T. Raines

Stereoelectronic effects modulate molecular reactivity and conformation. For example, the nucleophilic attack at a carbonyl carbon is preferred along the B€urgi Dunitz trajectory. This orientational preference stems from a stereoelectronic effect arising from the delocalization of an electron pair (n) of a nucleophile into an antibonding orbital (π*) of the carbonyl group. Our experimental and ...

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 ...

2013
Jia Guo Yanhong Xu Shangbin Jin Long Chen Toshihiko Kaji Yoshihito Honsho Matthew A. Addicoat Jangbae Kim Akinori Saeki Hyotcherl Ihee Shu Seki Stephan Irle Masahiro Hiramoto Jia Gao Donglin Jiang

Covalent organic frameworks are a class of crystalline organic porous materials that can utilize π-π-stacking interactions as a driving force for the crystallization of polygonal sheets to form layered frameworks and ordered pores. However, typical examples are chemically unstable and lack intrasheet π-conjugation, thereby significantly limiting their applications. Here we report a chemically s...

Journal: :Nano Energy 2023

Owing to the high electron delocalization in 2D ultrathin regions derived from π-d conjugations, electrically conductive metal-organic frameworks (MOFs) are widely used electronic applications but mostly for rigid devices. The interaction mechanism between MOFs and flexible substrates remains unclear, which cannot meet increasing demand next-generation wearable electronics. Herein, copper-benze...

Journal: :Organic & biomolecular chemistry 2014
Olga A Stasyuk Halina Szatylowicz Tadeusz M Krygowski

The stability and aromaticity of thirteen known thymine tautomers were studied in the gas phase at the B3LYP/6-311++G(2d,2p) computational level. It was found that they do not follow the Hückel 4N + 2 rule when the energetic criterion is considered, but they follow it when aromaticity indices, such as NICS, HOMA and the sum of the Wiberg bond indices, are applied. It was shown that the stabilit...

Journal: :Physical chemistry chemical physics : PCCP 2015
Martina Zámečníková Dana Nachtigallová

The excited state dynamics of a N-methylformamide dimer in complex with water molecules has been studied using the complete active space self-consistent field (CASSCF) and CAS perturbation theory to the second order (CASPT2) methods. The extent of delocalization of the first two excited states resulting from (n → π*) transitions on both monomers was monitored during the time course of on-the-fl...

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