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A Benzene‐1,3,5‐Triaminyl Radical Fused with Zn II ‐Porphyrins: Remarkable Stability and a High‐Spin Quartet Ground State
Author(s) -
Shimizu Daiki,
Osuka Atsuhiro
Publication year - 2018
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.201801080
Subject(s) - porphyrin , chemistry , ground state , benzene , steric effects , photochemistry , crystallography , atomic physics , organic chemistry , physics
A benzene‐1,3,5‐triaminyl radical fused with three Zn II ‐porphyrins was synthesized through a three‐fold oxidative fusion reaction of 1,3,5‐tris(Zn II ‐porphyrinylamino)benzene followed by oxidation with PbO 2 as key steps. This triaminyl radical has been shown to possess a quartet ground state with a doublet–quartet energy gap of 3.1 kJ mol −1 by superconducting quantum interference device (SQUID) studies. Despite its high‐spin nature, this triradical is remarkably stable, which allows its separation and recrystallization under ambient conditions. Moreover, this triradical can be stored as a solid for more than one year without serious deterioration. The high stability of the triradical is attributed to effective spin delocalization over the porphyrin segments and steric protection at the nitrogen centers and the porphyrin meso positions.