Tetraaza[1.1.1.1]m,p,m,p‑cyclophane Diradical Dications Revisited: Tuning Spin States by Confronted Arenes

Diradical dications of two kinds of alternate-meta-para-linked tetraazacyclophanes in which p-phenylene (1) and 9,10-anthracenylene (2a) moieties are embedded in their macrocyclic backbones were successfully isolated as air-stable salts. The structures of 1 2+ and 2a 2+ were elucidated by X-ray anal...

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Bibliographic Details
Published in:Organic letters 2017-06, Vol.19 (12), p.3115-3118
Main Authors: Kurata, Ryohei, Sakamaki, Daisuke, Ito, Akihiro
Format: Article
Language:English
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Summary:Diradical dications of two kinds of alternate-meta-para-linked tetraazacyclophanes in which p-phenylene (1) and 9,10-anthracenylene (2a) moieties are embedded in their macrocyclic backbones were successfully isolated as air-stable salts. The structures of 1 2+ and 2a 2+ were elucidated by X-ray analysis, and significantly different types of structural deformation led to different spin density distributions due to the steric demand of the confronted arene moieties. The singlet–triplet energy gaps were determined to be +0.3 kcal mol–1 (+151 K) and −1.0 kcal mol–1 (−503 K) by SQUID measurements, indicating the triplet ground state for 1 2+ and the singlet ground state for 2a 2+.
ISSN:1523-7060
1523-7052
DOI:10.1021/acs.orglett.7b01229