title: Zethrene biradicals: how pro-aromaticity is expressed in the ground electronic state and in the lowest energy singlet, triplet, and ionic states.
abstract: A analysis of the electronic and molecular structures of new molecular materials based on zethrene is presented with particular attention to those systems having a central benzo-quinoidal core able to generate Kekulé biradicals whose stability is provided by the aromaticity recovery in this central unit. These Kekulé biradicals display singlet ground electronic states thanks to double spin polarization and have low-energy lying triplet excited states also featured by the aromaticity gain. Pro-aromatization is also the driving force for the stabilization of the ionized species. Moreover, the low energy lying singlet excited states also display a profound biradical fingerprint allowing to singlet exciton fission. These properties are discussed in the context of the size of the zethrene core and of its substitution. The work encompasses all known long zethrenes and makes use of a variety of experimental techniques, such as Raman, UV-Vis-NIR absorption, transient absorption, in situ spectroelectrochemistry and quantum chemical calculations. This study reveals how the insertion of suitable molecular modules (i.e., quinoidal) opens the door to new intriguing molecular properties exploitable in organic electronics.
authors: Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain.
authors: José Luis
authors: JL
authors: Zafra
authors: Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain.
authors: Rafael C
authors: RC
authors: González Cano
authors: Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain.
authors: M Carmen
authors: MC
authors: Ruiz Delgado
authors: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543.
authors: Zhe
authors: Z
authors: Sun
authors: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543.
authors: Yuan
authors: Y
authors: Li
authors: Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain.
authors: Juan T
authors: JT
authors: López Navarrete
authors: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543.
authors: Jishan
authors: J
authors: Wu
authors: Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain.
authors: Juan
authors: J
authors: Casado