Photophysical properties of the new phosphorescent platinum(II) and palladium(II) complexes of benzoporphyrins and chlorins

Several phosphorescent platinum(II) and palladium(II) complexes of tetrapyrrole dyes are prepared in an attempt to improve the compatibility with red laser diodes. The nature of meso-substituents in benzoporphyrin macrocycle is found to affect mainly the position of the Soret band and has little influence on the Q-bands. In rigid polymeric matrices these dyes possess more favourable photochemical properties than corresponding meso-tetraphenyltetrabenzoporphyrins. Platinum(II) chlorins show good compatibility with 635 nm laser diode and 632.8 line of He–Ne laser, and have moderate brightness with emission yields ∼2%. Photophysical properties and photostability of these dyes is assessed and compared with the known NIR-emitting oxygen indicators.