نتایج جستجو برای: Cyclic cumulenes

تعداد نتایج: 98374  

Journal: :Chemphyschem : a European journal of chemical physics and physical chemistry 2008
Xibin Gu Ralf I Kaiser Alexander M Mebel

During the last decade, experimental and theoretical studies on the unimolecular decomposition of cumulenes (H(2)C(n)H(2)) from propadiene (H(2)CCCH(2)) to hexapentaene (H(2)CCCCCCH(2)) have received considerable attention due to the importance of these carbon-bearing molecules in combustion flames, chemical vapor deposition processes, atmospheric chemistry, and the chemistry of the interstella...

Journal: :journal of physical & theoretical chemistry 2006
issa yavari hassan kabiri-fard

ab initio calculation at hf/6-31g* level of theory for geometry optimization and mp2/6-31g*//hf/6-31g* for a single point total energy calculation are reported for the important energyminimumconformations and transition-state geometries of of cyclodeca-1,2,3-triene (1). the mostfavorable conformation of 1 is a unsymmetrical twist-chair (1-tc) structure. degenerateinterconversion of 1-tc with it...

Journal: :Chemical communications 2018
Vicente G Jiménez Rubén Tapia Miguel A Medel Inês F A Mariz Tânia Ribeiro Victor Blanco Juan M Cuerva Ermelinda Maçôas Araceli G Campaña

Turning on the fluorescence of [3]cumulenes: we report the luminescence at room temperature upon aggregation of [3]cumulenes functionalized with propeller-like heptagon-containing polyphenylenes. These endgroups turn on the emission of a [3]cumulene by steric protection and restriction of their intramolecular rotations in the aggregates.

Journal: :Foundations 2022

Polyynes are alternations of single and triple bonds between carbon atoms, while cumulenes successions double bonds. Since the bond is strongest two recent preoccupations included synthesizing condensing cyclic polyynes their clusters. Density functional theory calculations predicted stable monocyclic rings formation for a number C atoms equal to or higher than 16. Alternative series Carbon Bor...

Journal: :Bulletin of the Chemical Society of Japan 1965

Journal: :Chemistry 2002
Michael Lewis Rainer Glaser

The results of a theoretical study of the one-, two- and three-water hydrolyses of carbodiimide and the one- and two-water hydrolyses of methyleneimine are presented. All structures were optimized and characterized at the MP2(full)/6-31G* level of theory. Energies for the one-water hydrolysis of carbodiimide were determined at numerous higher levels of theory, up to the QCISD(T)(fc)/6-311+G(3df...

Journal: :Organic & biomolecular chemistry 2014
Shoko Ueta Kazuo Hida Masaki Nishiuchi Yasuhiko Kawamura

The reaction of tetraarylbutatrienes (tetraaryl[3]cumulenes) with tetracyanoethene (TCNE), a strong electron-accepting molecule, at room temperature yielded novel four-membered ring compounds (head-to-tail unsymmetrically substituted diarylallene dimers) by [2 + 2] cycloaddition of the central C=C bond of the butatrienes. This reaction proceeded through a head-to-head symmetrically substituted ...

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