Phosphorescence in the near-IR range under stationary lamp excitation was studied of three palladium and three platinum complexes of benzocondensed hydroporphyrazine phthalocyanine analogues in which molecule one or two isoindole fragments are replaced by a hydrogenated pyrrole ring, giving macrocycles of photosynthetic pigments analogues of chlorin, bacteriochlorin and isobacteriochlorin types. For the first time, the phosphorescence spectra of trans-dibenzotetrahydroporphyrazines (for both platinum and palladium) have been registered, which detection failed during long time due to the record removal of 0-0 bands from the visible area (1.67 and 1.52 µm for Pd and Pt), and also because of the small quantum yield of phosphorescence. The fluorescence of these complexes was also detected.in the near-IR range. On the basis of comparison of experimental results with own and literature data for palladium complexes of a number of tetrapyrroles is shown the approximate additivity of the influence of structural factors — hydrogenation of pyrrole rings, aza- and benzo substitution — on the energy of the lower triplet state T1. The information obtained is essential for targeted creation of emitters in the near-IR range (1.0-1.7 µm).
Metal Complexes for Two-Photon Photodynamic Therapy: A Cyclometallated Iridium Complex Induces Two-Photon Photosensitization of Cancer Cells under Near-IR Light