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A Stable [4,3]Peri‐acene Diradicaloid: Synthesis, Structure, and Electronic Properties
Author(s) -
Shen JunJian,
Han Yi,
Dong Shaoqiang,
Phan Hoa,
Herng Tun Seng,
Xu Tingting,
Ding Jun,
Chi Chunyan
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202012328
Subject(s) - tetracene , diradical , acene , singlet fission , singlet state , chemistry , open shell , crystallography , materials science , photochemistry , molecule , triplet state , atomic physics , organic chemistry , physics , anthracene , excited state
The synthesis of peri‐fused acenes (peri‐acenes) with two or more rows is challenging due to their intrinsic open‐shell diradical character. Herein, we report the isolation of a derivative ( 4 ) of [4,3]peri‐acene in crystalline form. The parent [4,3]peri‐acene, containing three rows of tetracene, has a large diradical character ( y 0 =94.8 %) originating from aromatic stabilization. Due to kinetic blocking, 4 showed a reasonable stability with a half‐life time of ≈157 h under ambient conditions. Its structure was determined by X‐ray crystallographic analysis, and bond‐length analysis revealed eight localized Clar's sextets. 4 exhibited an open‐shell singlet ground state with a narrow electrochemical energy gap (1.13 eV) and a small singlet–triplet energy gap (−0.57 kcal mol −1 from SQUID measurements). Its electronic properties are compared with previously reported peri‐tetracene and teranthene derivatives.