Triptycene 1,2-Quinones and Quinols: Permeable Crystalline Redox-Active Molecular Solids

Suitably designed quinones and quinols are promising modules for the programmed construction of ordered redox-active molecular solids. To explore this potential, we have synthesized compounds 1-4, in which multiple 1,2-benzoquinone and 1,2-quinol units are attached to a triptycene core. The resulting molecules have topologies that disfavor efficient packing, and structural studies show that they crystallize to form open networks held together by characteristic attractive intermolecular forces, including O-H center dot center dot center dot O hydrogen bonds, C-H center dot center dot center dot O interactions, pi-stacking, and dipolar interactions. Remarkably, the resulting solids are permeable and can undergo reversible redox reactions without loss of crystallinity. Our work may thereby help lead to the design of robust carbon-based batteries with electrodes derived from quinones, quinols, and other redox-active molecules abundantly produced by nature.