Front Cover: What a Difference an Electron Makes: Structural Response of Saddle-Shaped Tetraphenylene to One and Two Electron Uptake (ChemistryEurope 5/2024)

Abstract

The Front Cover highlights the core transformation that occurs in a polycyclic aromatic hydrocarbon with a central eight-membered ring (tetrabenzocyclooctatetraene) upon chemical reduction. The dial at the bottom illustrates the controlled addition of charge to the system. In the charge states—neutral, anionic, and dianionic—the eight-membered ring core is highlighted in red, yellow, or green, respectively. These “stoplight” colors emphasize the experimental observations described in the paper, whereby going from the neutral to the monoanionic form results in only a small structural perturbation of the carbon framework, whereas the addition of the second electron triggers the formation of an energetically favorable “butterfly” dianion with a new C−C bond. Thus, the central eight-membered ring is transformed into two fused five-membered rings. More information can be found in the Research Article by R. Gershoni-Poranne, M. A. Petrukhina and co-workers (DOI: 10.1002/ceur.202400055).