Bent and twisted

• Verfasst von: Hornung, Julius [VerfasserIn]
• Verfasst von: Hübner, Olaf [VerfasserIn]
• Verfasst von: Kaifer, Elisabeth [VerfasserIn]
• Verfasst von: Himmel, Hans-Jörg [VerfasserIn]
• Titel: Bent and twisted
• Titelzusatz: the electronic structure of 2-azapropenylium ions obtained by guanidine oxidation
• Verf.angabe: Julius Hornung, Olaf Hübner, Elisabeth Kaifer, Hans-Jörg Himmel
• E-Jahr: 2016
• Jahr: 20 Apr 2016
• Umfang: 7 S.
• Fussnoten: Gesehen am 20.05.2020
• Titel Quelle: Enthalten in: Royal Society of ChemistryRSC Advances
• Ort Quelle: London : RSC Publishing, 2011
• Jahr Quelle: 2016
• Band/Heft Quelle: 6(2016), 45, Seite 39323-39329
• ISSN Quelle: 2046-2069
• DOI: doi:10.1039/C6RA04494H
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 169862073X

Abstract

New bis-2-azapropenylium ions are obtained by oxidation of guanidino-substituted aromatic compounds. The dications 12+ (1 = 1,4-bis-tetramethylguanidinobenzene) and 22+ (2 = 1,4-bis-guanidinobenzene) exhibit unexpected bent-twisted structures, that differ from the known 2-azapropenylium ion structures (linear-orthogonal 2-azaallenium ion or bent-planar 2-azaallylium ion), and resemble the structures of carbodicarbenes. Their electronic structure was analysed by a combination of experiments and quantum chemical calculations. The results indicate that the bent-planar structure is disfavoured for steric reasons, while the allene-type linear-orthogonal structure is also disfavoured due to the electron-donating groups that support the bent form. For these reasons a bent-twisted structure is adopted, in which the nitrogen atom is engaged with two different orbitals in π-bonding with the carbon π-system and in a weaker π-interaction with the CN2 group of the guanidino system.