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Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, Israel
› InstitutsangabenFunding Information This research was supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (Grant Agreement No. 850836, ERC Starting Grant “PolyHelix”). A.B. is supported by a PBC fellowship.
Twisting anthracene and higher acenes can alter their optical, magnetic, and electronic properties. To test the effect of twisting on the lower homologue, naphthalene, we synthesized tethered naphthalenophanes bearing alkyl bridges. Both X-ray structure and DFT calculations show that hexyl and butyl bridges induce a 6° and 12° end-to-end twist on the naphthalene unit, respectively. Attempts to increase the twisting further using shorter tethers resulted in an elimination product. Enantiomerically pure naphthalenophanes display strong chiroptical properties, which intensify with increasing twist. Attempts to induce bending, rather than twisting, using the same synthetic methodology, resulted in intermolecular dimerization, yielding macrocyclic naphthalenes. This work highlights the importance of steric hindrance in the synthesis of curved cyclophanes using the bridge formation approach.
