Heptacene: Characterization in Solution, in the Solid State, and in Films.
Acenes comprise an important class of organic semiconducting materials. As graphene nanoribbons of ultimate width, they are valuable atom-precise model systems for studying the properties of this form of nanoscale carbon materials. Heptacene is the smallest member of the acene series that could only be studied under matrix isolation conditions. Its existence in bulk had never been positively confirmed, despite efforts dating back more than 70 years. We report that the reduction of 7,16-heptacenequinone produces a mixture of two diheptacene molecules. The diheptacenes undergo thermal cleavage to heptacene at high temperatures in the solid state. Monitoring this cycloreversion by solid state13C cross-polarized magic angle spinning NMR reveals that solid heptacene has a half-life time of several weeks at room temperature. The diheptacenes are valuable precursors for generating films of heptacene by vapor phase deposition that can be studied below or at room temperature.
Institut für Organische Chemie, Universität Tübingen , Auf der Morgenstelle 18, 72076 Tübingen, Germany.
Ralf
R
Einholz
Flux Research Institute LLC , 11444 Rothschild Place, Dublin, California 94568, United States.
Treliant
T
Fang
Fachbereich Chemie, Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35032 Marburg, Germany.|FIAS, Goethe-Universität , Ruth-Moufang-Strasse 1, 60438 Frankfurt am Main, Germany.
Robert
R
Berger
Institut für Physikalische und Theoretische Chemie, Universität Tübingen , Auf der Morgenstelle 18, 72076 Tübingen, Germany.
Peter
P
Grüninger
Institut für Physikalische und Theoretische Chemie, Universität Tübingen , Auf der Morgenstelle 18, 72076 Tübingen, Germany.
Andreas
A
Früh
Institut für Physikalische und Theoretische Chemie, Universität Tübingen , Auf der Morgenstelle 18, 72076 Tübingen, Germany.
Thomas
T
Chassé
Institut für Physikalische und Theoretische Chemie, Universität Tübingen , Auf der Morgenstelle 18, 72076 Tübingen, Germany.
Reinhold F
RF
Fink
Institut für Organische Chemie, Universität Tübingen , Auf der Morgenstelle 18, 72076 Tübingen, Germany.
Holger F
0000-0001-5223-662X
HF
Bettinger