This study employs computational calculations and ultrafast spectroscopy to design and probe alternate isomerization in a bis-azobenzene molecule. The phenyl- and thiophenylazobenzene moieties exhibit independent switching under different wavelengths, advancing multi-photoswitch applications.

Abstract

To design efficient molecular information storage systems with multi-photoswitchable entities, orthogonal isomerization of the different switchable moieties is essential. Various challenges, like unintentional energy transfer, spectral overlap, and other energy dissipation channels, have to be addressed by intelligent molecule design. In this context, we took advantage of calculations to design a bis-azobenzene switch, which consists of a phenyl- and a thiophenylazobenzene moiety in meta-connection to reduce π-conjugation. Ultrafast spectroscopy and computational studies confirmed that this bis-photoswitch exhibits alternating orthogonal switching behavior when irradiated with light of different wavelengths. These results represent a significant advancement toward the development of efficient and adaptable organic multi-photoswitches for applications, such as information storage, molecular machines, or smart materials.