Synthesis of Twisted [ n ]Cycloparaphenylene by Alkene Insertion

Mono‐alkene‐inserted [ n ]cycloparaphenylenes 1 [(ene)‐[ n ]CPP] with n= 6, 8, and 10, mono‐ ortho ‐phenylene‐inserted [6]CPP 2 , and di‐alkene‐insertved [ n ]CPP 3 [(ene) 2 ‐[ n ]CPP] with n= 4, 6, and 8 were synthesized by fusing CPP precursors and alkene or ortho‐ phenylene groups through coupling reactions. Single‐crystal X‐ray diffraction analyses reveal that the strips formed by the π‐surfaces of 1 and 2 exhibited a Möbius topology in the solid state. While the Möbius topology in the parent 1 and 2 in solution was lost due to the free rotation of the paraphenylene unit even at low temperatures, ene‐[6]CPP 4 with eight 1‐pyrrolyl groups preserved the Möbius topology even in solution. Despite a twist, 1 has in‐plane conjugation and possesses a unique size dependence of the electronic properties: namely, the opposite size dependency of the HOMO–LUMO energy relative to conventional π‐conjugated molecules.