Gallium(III) corrole complexes as near-infrared emitter – synthesis, computational and photophysical study

We report on the chemical synthesis and characterization of free-base A2B- and A3-meso-TIPS ethynyl corroles, which serve as a precursor for metalation with gallium(III)chloride and subsequent in-situ sila Sonogashira cross-coupling reaction. Under ambient conditions and with a common catalyst system the reaction with different aryliodides proved to be successful. Compared to the well-known Ga(III)-pyr-5,10,15-trispentafluorophenylcorrole complex, the emission wavelengths of such gallium(III) corroles complexes could be shifted bathochromically by up to ~3100 cm-1 to the near-infrared region (NIR). The described synthetic procedure establishes a facile way to obtain organic near-infrared-emitters based on gallium(III) meso-aryl-ethynyl corrole complexes.