1. Contribution from the Institute of Organic Chemistry and Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander Universität Erlangen-Nürnberg, Henkestrasse 42, 91054 Erlangen, Germany, and Institute of Physical Chemistry and Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany