Quinoidal Azaacenes: 99 % Diradical Character |
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Authors: | Sebastian N. Intorp,Manuel Hodecker,Matthias Mü ller,Olena Tverskoy,Marco Rosenkranz,Evgenia Dmitrieva,Alexey A. Popov,Frank Rominger,Jan Freudenberg,Andreas Dreuw,Uwe H. F. Bunz |
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Abstract: | Quinoidal azaacenes with almost pure diradical character (y=0.95 to y=0.99) were synthesized. All compounds exhibit paramagnetic behavior investigated by EPR and NMR spectroscopy, and SQUID measurements, revealing thermally populated triplet states with an extremely low‐energy gap ΔEST′ of 0.58 to 1.0 kcal mol?1. The species are persistent in solution (half‐life≈14–21 h) and in the solid state they are stable for weeks. |
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Keywords: | acenes heteroaromatics radicals structure elucidation synthetic methods |
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