Photophysical and electrochemical properties of two<i>trans</i>-A<sub>2</sub>B-corroles: differences between phenyl or pyrenyl groups at the<i>meso</i>-10 position
Thiago V. Acunha, Henrique F.V. Victória, Klaus Krambrock, Amanda C. Marques, Luiz Antônio S. Costa, Bernardo A. Iglesias
Abstract
B-corroles having phenyl substituents at that position. In contrast to the model meso-substituted corrole, the new pyrenyl-corrole shows slightly red-shifted absorption bands and blue-shifted emission, slightly higher fluorescence quantum yield, and more importantly, it shows better photo-stability under white-light illumination. Theoretical calculations were used to determine the electronic transitions and geometries of the singlet and triplet excited states (TD-DFT and NTO). Moreover, we demonstrate that the pyrenyl-corrole in analogy to previously studied model corroles is able to generate reactive oxygen species (ROS) under visible light using photo-degradation of 1,3-diphenylisobenzofuran (DBPF), a singlet oxygen quencher, and EPR spectroscopy allied with the spin-trapping method is used for identifying singlet oxygen species. The results show that the pyrenyl unit attached at the meso-10-position of the corrole increases the photo-stability and efficiency in ROS generation compared to the phenyl substituent.