An Unusually Small Singlet-Triplet Gap in a Quinoidal 1,6-Methano[10]annulene Resulting from Baird's 4n π-Electron Triplet Stabilization.
Angew Chem Int Ed Engl
; 54(20): 5888-93, 2015 May 11.
Article
de En
| MEDLINE
| ID: mdl-25833411
ABSTRACT
Within the continuum of π-extended quinoidal electronic structures exist molecules that by design can support open-shell diradical structures. The prevailing molecular design criteria for such structures involve proaromatic nature that evolves aromaticity in open-shell diradical resonance structures. A new diradical species built upon a quinoidal methano[10]annulene unit is synthesized and spectroscopically evaluated. The requisite intersystem crossing in the open-shell structure is accompanied by structural reorganization from a contorted Möbius aromatic-like shape in S0 to a more planar shape in the Hückel aromatic-like T1. This stability was attributed to Baird's Rule which dictates the aromaticity of 4n π-electron triplet excited states.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Langue:
En
Journal:
Angew Chem Int Ed Engl
Année:
2015
Type de document:
Article