title: A Stable Saddle-Shaped Polycyclic Hydrocarbon with an Open-Shell Singlet Ground State.
abstract: Diindeno-fused bischrysene, a new diindeno-based polycyclic hydrocarbon (PH), was synthesized and characterized. It was elucidated in detailed experimental and theoretical studies that this cyclopenta-fused PH possesses an open-shell singlet biradical structure in the ground state and exhibits high stability under ambient conditions (t1/2=39 days). The crystal structure unambiguously shows a novel saddle-shaped π-conjugated carbon skeleton due to the steric hindrance of the central cove-edged bischrysene unit. UV/Vis spectral measurements revealed that the title molecule has a very narrow optical energy gap of 0.92 eV, which is consistent with the electrochemical analysis and further supported by density functional theory (DFT) calculations.
authors.affiliation: Center for Advancing Electronics Dresden (cfaed), Department of Chemistry and Food Chemistry, Technische Universität Dresden, 01062, Dresden, Germany.
authors.forename: Ji
authors.initials: J
authors.lastname: Ma
authors.affiliation: Center for Advancing Electronics Dresden (cfaed), Department of Chemistry and Food Chemistry, Technische Universität Dresden, 01062, Dresden, Germany.
authors.forename: Junzhi
authors.initials: J
authors.lastname: Liu
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Baumgarten
authors.affiliation: Center for Advancing Electronics Dresden (cfaed), Department of Chemistry and Food Chemistry, Technische Universität Dresden, 01062, Dresden, Germany.
authors.forename: Yubin
authors.initials: Y
authors.lastname: Fu
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, 361005, Xiamen, China.
authors.forename: Yuan-Zhi
authors.initials: YZ
authors.lastname: Tan
authors.affiliation: Institute for Materials Science, Max Bergmann Center of Biomaterials, Dresden Center for Computational Materials Science, Technische Universität Dresden, 01062, Dresden, Germany.
authors.forename: Karl Sebastian
authors.initials: KS
authors.lastname: Schellhammer
authors.affiliation: Institute for Materials Science, Max Bergmann Center of Biomaterials, Dresden Center for Computational Materials Science, Technische Universität Dresden, 01062, Dresden, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Ortmann
authors.affiliation: Institute for Materials Science, Max Bergmann Center of Biomaterials, Dresden Center for Computational Materials Science, Technische Universität Dresden, 01062, Dresden, Germany.
authors.forename: Gianaurelio
authors.initials: G
authors.lastname: Cuniberti
authors.affiliation: Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Strasse 6, 01069, Dresden, Germany.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Komber
authors.affiliation: Center for Advancing Electronics Dresden (cfaed), Department of Chemistry and Food Chemistry, Technische Universität Dresden, 01062, Dresden, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Berger
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Müllen
authors.affiliation: Center for Advancing Electronics Dresden (cfaed), Department of Chemistry and Food Chemistry, Technische Universität Dresden, 01062, Dresden, Germany.
authors.forename: Xinliang
authors.initials: X
authors.lastname: Feng
keywords: aromaticity; biradicals; electronic structure; polycyclic hydrocarbons; saddle conformation