New Design Strategies for the Preparation and Linking of Cyclopenta-Fused Polycyclic Aromatic Hydrocarbons

Author

Yachu Du, Southern Illinois University CarbondaleFollow

Date of Award

6-1-2021

Degree Name

Doctor of Philosophy

Department

Chemistry

First Advisor

Plunkett, Kyle

Abstract

In this contribution, we demonstrate a new strategy to build electron deficient centers and electron accepting compounds through fusion of cyclopentene units. Two series of cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs) were designed and synthesized as possible n-type semiconductors. One series of CP-PAHs were prepared by a palladium catalyzed cyclopentannulation reaction from precursors derived from the low-cost dye Vat Orange 3 (4,10-dibromoanthanthrone). The new cyclopenta-anthanthrene compounds possessed reduced optical and electrochemical gaps compared to anthanthrene derivatives and were electron acceptors with lowest unoccupied molecular orbital energies of ~ -3.4 eV to -3.9 eV. In a second research direction, CP-PAH chromophores were linked through two five-membered rings to create a new semiconductor linkage strategy. We show this new linker design can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.