Ground Triplet Spirobiradical: 2,2',7,7'-Tetra( tert-butyl)-9,9'(10 H,10' H)-spirobiacridine-10,10'-dioxyl

Takuya Kanetomo; Kana Ichihashi; Masaya Enomoto; Takayuki Ishida

doi:10.1021/acs.orglett.9b00901

Ground Triplet Spirobiradical: 2,2',7,7'-Tetra( tert-butyl)-9,9'(10 H,10' H)-spirobiacridine-10,10'-dioxyl

Org Lett. 2019 Jun 7;21(11):3909-3912. doi: 10.1021/acs.orglett.9b00901. Epub 2019 Apr 11.

Authors

Takuya Kanetomo¹, Kana Ichihashi², Masaya Enomoto¹, Takayuki Ishida²

Affiliations

¹ Tokyo University of Science , 1-3 Kagurazaka , Shinjuku-ku, Tokyo 162-8601 , Japan.
² The University of Electro-Communications , 1-5-1 Chofugaoka , Chofu, Tokyo 182-8585 , Japan.

PMID: 30973232
DOI: 10.1021/acs.orglett.9b00901

Abstract

A new spirobiradical, 2,2',7,7'-tetra( tert-butyl)-9,9'(10 H,10' H)-spirobiacridine-10,10'-dioxyl, was prepared. The crystallographic analysis clarified the D_{2 d} molecular structure, suggesting the degeneracy of SOMOs. The magnetic study revealed that intramolecular ferromagnetic coupling was operative with 2 J/ k_B = +23(1) K. To the best of our knowledge, the ferromagnetic coupling parameter is the largest ever reported for a paramagnetic spiro compound.