Acene-Based Cyclophanes: Twist Introduced by an Ether Bridge

[n]Cyclophanes are a special class of organic compounds, composed of at least one aromatic system and one bridge. Various aromatic and polyaromatic systems are used to build cyclophanes under diverse synthetic approaches that find applications in synthetic chemistry, host–guest chemistry, supramolecular chemistry, asymmetric synthesis, natural products, functional p-materials, and polymer chemistry among others.^[1] Particularly, use of chiral cyclophanes has been explored on many occasions. Pyrene is the only conjugated system that has been reported to form cyclophanes with an end-to-end tethering. This tethering introduces strain that impulses a bent in the conjugated polyaromatic backbone. Twisting and bending in polyaromatic systems are both sterically and electronically dissimilar phenomena that produce sublime differences in their chiroptical and optoelectronic properties. Here we describe a simple procedure to achieve acene cyclophanes bridged by an ether linker. We also report the unique properties resulting from the strain-induced twisting and its effect on the backbone structure and aromaticity.

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[1] P. G. Ghasemabadi, T, Yao, G. J. Bodwell, Chem. Soc. Rev., 2015, 44, 6494.