Magnetically Induced Ring-Current Strengths in Möbius Twisted Annulenes

Abstract

The topology of twisted molecular rings is characterized by the linking number, which is equal to the sum of the twist—a local property of the molecular frame—and the writhe—a global parameter, which represents the bending of the molecular ring. In this work, we investigate a number of cyclic all-trans C40H40 annulenes with varying twisting numbers for a given linking number and their dications. The aromatic character is assessed by calculating ring-current strength susceptibilities using the gauge-including magnetically induced currents (GIMIC) method, which makes it possible to conduct a systematic study of the relation between the topology and aromaticity of twisted molecules. We found that the aromatic properties of the investigated Möbius twisted molecules are not only dependent on the linking number as previously suggested but also depend strongly on the partitioning of the linking number into the twist and writhe contributions.