Work

What a Difference an Electron Makes: Structural Response of Saddle‐Shaped Tetraphenylene to One and Two Electron Uptake

Year: 2024

Type: article

Abstract: Cyclooctatetraene (COT) and COT2− dianion are well‐known as archetypical non‐aromatic and aromatic systems, respectively. However, despite a wealth of studies the effect of one electron addition to the eight‐membered ring remains equivocal. Herein, we report the first stepwise electron addition to tetrabenzo[a,c,e,g]cyclooctatetraene (TBCOT or tetraphenylene), accompanied by isolation and structural characterization of the mono‐ and doubly‐reduced anions. The X‐ray crystallographic study reveals only a small asymmetric distortion of the saddle‐shaped core upon one electron uptake. In contrast, the doubly‐reduced product exhibits a severely twisted conformation, with a new C−C bond separating the COT ring into two fused 5‐membered rings. The reversibility of the two‐fold reduction and bond rearrangement is demonstrated by NMR spectroscopy. In agreement with experimental results, computational analysis confirms that the reduction‐induced core rearrangement requires the addition of the second electron.

Source: ChemistryEurope

DOI: 10.1002/ceur.202400055

Authors: Yikun Zhu, Zheng Zhou, Zheng Wei, Alexandra Tsybizova, Renana Gershoni‐Poranne, Marina A. Petrukhina