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The Tetraaza[1.1.1.1] m , p , m , p ‐cyclophane Dication: A Triplet Diradical Having Two m ‐Phenylenediamine Radical Cations Linked by Twisted Benzenes
Author(s) -
Ito Akihiro,
Ono Yukiharu,
Tanaka Kazuyoshi
Publication year - 2000
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/(sici)1521-3773(20000317)39:6<1072::aid-anie1072>3.0.co;2-1
Subject(s) - dication , diradical , electron paramagnetic resonance , chemistry , phenylene , cyclophane , quantum chemical , crystallography , photochemistry , radical ion , antiaromaticity , stereochemistry , molecule , aromaticity , polymer , physics , ion , organic chemistry , crystal structure , quantum mechanics , excited state , singlet state
Macrocyclization due to the m ‐phenylene tether is responsible for the stabilization of the azacyclophane‐based dication 1 2+ . EPR (see picture) and quantum‐chemical studies indicate that 1 2+ , which can be regarded as two m ‐phenylenediamines linked by two p ‐phenylenes, is a triplet diradical. Its properties differ from those of the open‐chain version 2 2+ .