Photoinduced Pedalo‐Type Motion in an Azodicarboxamide‐Based Molecular Switch

Well‐defined structural changes of molecular units that can be triggered by light are crucial for the development of photoactive functional materials. Herein, we report on a novel switch that has azodicarboxamide as its photo‐triggerable element. Time‐resolved UV‐pump/IR probe spectroscopy in combination with quantum‐chemical calculations shows that the azodicarboxamide functionality, in contrast to other azo‐based chromophores, does not undergo trans–cis photoisomerization. Instead, a photoinduced pedalo‐type motion occurs, which because of its volume‐conserving properties enables the design of functional molecular systems with controllable motion in a confined space. Motion without volume change: By combining time‐resolved infrared spectroscopy with quantum‐mechanical calculations, a volume‐conserving pedalo‐type motion was studied in a molecular switch. These azodicaboxamide‐based systems have the potential to open a new realm in the achievement of motion in a confined space.