Structural modulation of the absorption spectrum in cyclometalated iridium complexes for artificial photosynthesis

JUAN MANUEL RODRIGUEZ SAMIA; MARÍA ANA FOI; FABIO DOCTOROVICH; FLORENCIA DI SALVO; DAMIÁN E. BIKIEL

Chascomús

Congreso; IV LABIC; 2014

Photosynthesis is the most important photoreactive process known.(1) Using light from the Sun, plants and other organisms are capable to produce high-energy compounds. Mimicking Nature using synthetic compounds for capturing solar energy is one of the approaches most interesting to overcome the future global energy needs. The mot studied sensitizers are derived from [Ru(bpy)3]2+, which has been studied during the last 30 years.(2) After absorbing a photon, the excited state of these compounds reaches an excited state that is a more powerful oxidant than the basal state. Developing new sensitizers is important because are the responsible of the capture efficiency and transduction of photons. A new generation of iridium catalysts and sensitizers have been appeared recently, based in several combinatorial chemistry studies.(3)(4) The principal advantages of these new compounds are the easiness of the excitation energy tuning, higher reduction potential of the photoexcited state, robust from a chemical point of view, easiness for HOMO-LUMO energy tuning and water solubility in a high range pH. In this work we explore how the UV spectrum is modified by breaking the connection of the rings in the bipyridine ligand and how to tune the spectrum by means of pyridine substitutions.