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Stable Cross‐Conjugated Tetrathiophene Diradical
Author(s) -
Zhang Cheng,
Medina Rivero Samara,
Liu Wuyue,
Casanova David,
Zhu Xiaozhang,
Casado Juan
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201904153
Subject(s) - diradical , conjugated system , chemistry , singlet state , pyrrole , acceptor , photochemistry , molecule , computational chemistry , organic chemistry , polymer , excited state , physics , nuclear physics , condensed matter physics
A tetracyano quinoidal tetrathiophene, having a central bi(thieno[3,4‐c]pyrrole‐4,6‐dione) acceptor, has been studied. The recovered aromaticity of the thiophenes produces a diradical species with cross‐conjugation between the inter‐dicyano and inter‐dione acceptor paths. A diradical character of y 0 =0.61 and a singlet–triplet gap of −2.76 kcal mol −1 were determined. Competition between the two cross‐conjugated paths enhances the disjointed character of the SOMOs and results in the confinement of the diradical to the molecular center, enabling a thermodynamic diradical stabilization featuring a half‐life of 262 hours. Cross‐conjugation effects have been also addressed in the anionic species (up to a radical trianion).