Isolable Triradical Trication of Hexaaza[16]paracyclophane with Embedded 9,10-Anthrylenes: A Frustrated Three-Spin System

Ryohei Kurata; Daisuke Sakamaki; Masashi Uebe; Mariko Kinoshita; Tetsuo Iwanaga; Takashi Matsumoto; Akihiro Ito

doi:10.1021/acs.orglett.7b02088

Isolable Triradical Trication of Hexaaza[1₆]paracyclophane with Embedded 9,10-Anthrylenes: A Frustrated Three-Spin System

Org Lett. 2017 Aug 18;19(16):4371-4374. doi: 10.1021/acs.orglett.7b02088. Epub 2017 Aug 7.

Authors

Ryohei Kurata¹, Daisuke Sakamaki¹, Masashi Uebe¹, Mariko Kinoshita¹, Tetsuo Iwanaga², Takashi Matsumoto³, Akihiro Ito¹

Affiliations

¹ Department of Molecular Engineering, Graduate School of Engineering, Kyoto University , Nishikyo-ku, Kyoto 615-8510, Japan.
² Department of Chemistry, Faculty of Science, Okayama University of Science , 1-1 Ridaicho, Kita-ku, Okayama 700-0005, Japan.
³ X-ray Research Laboratory, Rigaku Corporation , Matsubara-cho 3-9-12, Akishima, Tokyo 196-8666, Japan.

PMID: 28783366
DOI: 10.1021/acs.orglett.7b02088

Abstract

A new derivative of hexaaza[1₆]paracyclophane in which p-phenylenes are alternately replaced by 9,10-anthrylenes was prepared to investigate the impact on overall π-conjugation as well as conformational change of the macrocycle. The charge and spin distribution for one-electron and three-electron oxidation of the macrocycle was elucidated by means of electrochemical, spectroelectrochemical, EPR spectroscopic, and SQUID magnetometric methods. In particular, the triradical trication was successfully isolated as an air-stable salt, and moreover, its structure was disclosed by X-ray analysis. The triradical trication was characterized as a spin-frustrated three-spin system with the antiferromagnetic exchange interaction (J/k_B ≃ - 74 K).

Publication types

Research Support, Non-U.S. Gov't