Photoswitchable Organocatalysts

The combination of photochromism and molecular property changes promises an exquisite external control over chemical function with high temporal and spatial resolution. The development of photoswitchable catalysts, which possess two optically independently addressable switching states with drastically different catalytic activity, is at the heart of the project. In particular, the large geometrical changes associated with the E-Z isomerization of an azobenzene photochrome will be utilized to selectively deshield a sterically blocked nucleophilic/basic centre and therefore transform the molecule into a catalytically more active form. After successful design of photoswitchable catalysts based on tertiary amines and N-heterocyclic carbenes, respectively, they will be immobilized and investigated with regard to chemical surface patterning. Within the context of the priority program Organocatalysis (SPP 1179), the project will provide a new promising concept to third project area Applications that in addition to catalyst immobilization allows for an external control over its activity by light.