Premium
Synthesis of the Unknown Indeno[1,2‐ a ]fluorene Regioisomer: Crystallographic Characterization of Its Dianion
Author(s) -
Dressler Justin J.,
Zhou Zheng,
Marshall Jonathan L.,
Kishi Ryohei,
Takamuku Shota,
Wei Zheng,
Spisak Sarah N.,
Nakano Masayoshi,
Petrukhina Marina A.,
Haley Michael M.
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201709282
Subject(s) - fluorene , structural isomer , diradical , chemistry , conjugated system , molecule , characterization (materials science) , crystallography , stereochemistry , materials science , organic chemistry , nanotechnology , physics , polymer , singlet state , nuclear physics , excited state
Abstract Of the five possible indenofluorene regioisomers, examples of a fully conjugated indeno[1,2‐ a ]fluorene scaffold have so far remained elusive. This work reports the preparation and characterization of 7,12‐dimesitylindeno[1,2‐ a ]fluorene as a highly reactive species. Experimental and computational data support the notion of a molecule with pronounced diradical character that exists in a triplet ground state. As such, both NICS and ACID calculations suggest that the indeno[1,2‐ a ]fluorene scaffold is weakly Baird aromatic. Reduction of the unstable red solid with Cs metal produces the dianion of the title compound, from which single crystals could be obtained and X‐ray data acquired, thus fully corroborating the proposed indeno[1,2‐ a ]fluorene hydrocarbon core.