Twist localisation in single, double and triple twisted Möbius cyclacenes†

The AM1 and ab initio calculated geometries of Möbius strips formed by imparting one, two or three twists to cyclacenes of various lengths reveal a localisation of the twist over 2–4 benzo rings. Various properties of these systems are reported, including the geometries, the form of the highest occupied molecular orbitals, the electrostatic potential, and the charge distributions in neutral, 6+ and 6− forms of these molecules. Factors influencing the localising tendency are discussed.