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

• DOI: 10.1021/jacs.0c09941
• Publication Date: 2020-11-10T15:57:59Z
• Authors: Harrison M. Bergman; Gavin R. Kiel; Ryan J. Witzke; David P. Nenon; Adam M. Schwartzberg; Yi Liu; T. Don Tilley
• Keywords: Pentacene; Singlet fission

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 control over these interactions, but few examples exist for pentacene due inherent synthetic challenges. In this work, zirconocene-mediated alkyne coupling was used as dynamic covalent C–C bond forming reaction synthesize two geometrically distinct, pentacene-containing macrocycles gram scale in four or fewer steps. Both undergo singlet fission solution with rates that differ by an order magnitude, while the rate triplet recombination is approximately same. This independent modulation decay desirable design efficient materials. The dimeric macrocycle adopts columnar packing motif solid state large void spaces between units crystal lattice.