Visible light-driven photophysics and photochemistry of water-soluble metalloporphyrins

Lanthanide(III) porphyrins are of typical SAT complexes, the photophysical and-chemical features of which can be tuned by the size of the metal center. Anionic, early lanthanide(III) mono- and bisporphyrin complexes exhibit very similar photoinduced properties as a consequence of a special type of aggregation, through the peripheral substituents. The rather slow formation of complexes and transformation between the mono- and bisporphyrins can be accelerated by the irradiation of the system. These by-processes play considerable roles beside the photoredox degradation and demetalation. Depending on the wavelength of irradiation, two types of photoproducts can appear: during the photolysis at the Soret-band, a radical type intermediate can be observed, which disappears in dark. However, irradiation at the Q-bands, generates the formation of a new, stable photoproduct.