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Shape-Selective Synthesis of Pentacene Macrocycles and the Effect of Geometry on Singlet Fission

revised on 19.09.2020, 03:14 and posted on 21.09.2020, 07:33 by Harrison Bergman, Gavin Kiel, Ryan J. Witzke, David P. Nenon, Adam M. Schwartzberg, Yi Liu, T. Don Tilley

Pentacene’s extraordinary photophysical and electronic properties are highly dependent on intermolecular, through-space interactions. Macrocyclic arrangements of chromophores have been shown to provide a high level of control over these interactions, but few examples exist for pentacene due to inherent synthetic challenges. In this work, zirconocene-mediated alkyne coupling was used as a dynamic covalent C-C bond forming reaction to synthesize two geometrically distinct, pentacene-containing macrocycles on a gram scale and in four or fewer steps. Both macrocycles undergo singlet fission in solution, with rates that differ by an order of magnitude while the rate of triplet recombination is approximately the same. This independent modulation of singlet and triplet decay rates is highly desirable for the design of efficient singlet fission materials. The dimeric macrocycle adopts a columnar packing motif in the solid state, with large void spaces between pentacene units of the crystal lattice.


NSF CHE-1708210


Email Address of Submitting Author


UC Berkeley


United States

ORCID For Submitting Author


Declaration of Conflict of Interest


Version Notes

Version 1.1