Optical Properties of Novel Conjugated Nanohoops: Revealing the Effects of Topology and Size

The unique properties of chemical materials are usually related to the topology and size of their constituent unit. Inspired by a previous report on the synthesis of a separable catenane composed of two Mobius-conjugated nanohoops, we theoretically predicted the optical properties of the Mobius monomer, its Huckel analogue, and some structures derived from them. The underlying reasons for the effects of topology and size on molecular (hyper)polarizability and the absorption spectrum were explored from the electronic structure level by means of several analytical methods, including the two-level model, (hyper)polarizability density analysis, and the (hyper)polarizability contribution decomposition. This work is conducive to providing rational design ideas for those who are committed to discovering and synthesizing nanoscale cyclic molecules with special optical properties.