Bis-Copper(II)/π-Radical Multi-Heterospin System with Non-innocent Doubly N-Confused Dioxohexaphyrin(1.1.1.1.1.0) Ligand

Kazuhisa Yamasumi; Keiichi Nishimura; Yutaka Hisamune; Yusuke Nagae; Tomoki Uchiyama; Kazutaka Kamitani; Tomoyasu Hirai; Maiko Nishibori; Shigeki Mori; Satoru Karasawa; Tatsuhisa Kato; Ko Furukawa; Masatoshi Ishida; Hiroyuki Furuta

doi:10.1002/chem.201704321

Bis-Copper(II)/π-Radical Multi-Heterospin System with Non-innocent Doubly N-Confused Dioxohexaphyrin(1.1.1.1.1.0) Ligand

Chemistry. 2017 Nov 2;23(61):15322-15326. doi: 10.1002/chem.201704321. Epub 2017 Oct 11.

Affiliations

¹ Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems, Kyushu University, Fukuoka, 819-0395, Japan.
² Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka, 819-0395, Japan.
³ Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo, 679-5198, Japan.
⁴ Faculty of Engineering Sciences, Kyushu University, Fukuoka, 816-8580, Japan.
⁵ Advanced Research Support Center, Ehime University, Matsuyama, 790-8577, Japan.
⁶ Division of Pharmaceutical Chemistry, Showa Pharmaceutical University, Machida, 194-8543, Japan.
⁷ Institute for Liberal Arts and Sciences, Kyoto University, Kyoto, 606-8501, Japan.
⁸ Center for Instrumental Analysis, Institute for Research Promotion, Niigata University, Niigata, 950-2181, Japan.

PMID: 28906573
DOI: 10.1002/chem.201704321

Abstract

A contracted doubly N-confused dioxohexaphyrin(1.1.1.1.1.0) complex consisting of two paramagnetic copper metals and open-shell π-radical ligand was synthesized as a new multi-heterospin motif. X-ray spectroscopy supported the divalent character of the inner copper centers, and electron paramagnetic resonance and magnetometric studies suggested the presence of unpaired d electrons strongly antiferromagnetically coupled with π-radicals delocalized on the macrocycle. The 25 π non-innocent dioxohexaphyrin ligand allowed the facile interconversion between antiaromatic 24 π and aromatic 26 π species, respectively, upon redox reactions.

Keywords: aromaticity; copper; hexaphyrin; metal complex; redox non-innocence.