Photobasic transition-metal complexes

Transition-metal complexes, which exhibit photobasic properties, are highly promising for chemical applications where the proton abstraction represents one key step. Photobases feature an increased basicity in the excited state and, in particular, molecules which offer this property upon excitation with visible light are highly attractive. This criterium is met by transition-metal complexes which bear a basic substituent. Due to a metal-to-ligand charge transfer (MLCT), electron density in the substituent is increased - it becomes more basic. In here, we would like to elaborate the concept of photobases at the example of transition-metal complexes and provide an overview of the up-to-now available literature.