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Porphyrins bearing imidazolium salts were synthesized and used as N-heterocylic carbene (NHC) precursors for the preparation of gold(I) complexes. The dark toxicity and phototoxicity of the obtained compounds were investigated in vitro on MCF-7 breast cancer cells. The obtained data showed that porphyrins equipped with imidazolium salts are non-toxic in the dark and present interesting photodynamic properties. On the contrary, corresponding NHC-gold(I) complexes are not suitable photosensitizers for photodynamic therapy (PDT) applications. Their dark toxicity strongly depends on the nature of the linker between the porphyrin core and the NHC. This work was extended to the synthesis of a pyropheophorbide a derivative with a pendant imidazolium group for PDT applications using excitation wavelengths of 450 nm, 545 nm, and importantly of 650 nm. [ABSTRACT FROM AUTHOR]

Porphyrins fused to N -heterocyclic carbenes (NHCs) 1M , with inner metal M = Ni, Cu, Zn and H2, were used to synthesize palladium(II) complexes. These complexes behaved as precatalysts for high-temperature Mizoroki–Heck reactions between iodobenzene and styrene. Despite similar electronic properties between 1M ligands, catalytic activity was found to significantly depend on the presence, or not, of a central metal incorporated in the porphyrin core: a conversion of iodobenzene between 80–90% was observed with metalloporphyrins (M = Ni, Cu and Zn), whereas only 30% was observed with free-base porphyrins (M = H2) after 10 h. Palladium leaching and subsequent trapping of free palladium in the inner core of the free-base porphyrin modified the concentration of Pd(0) active species and may explain the lower catalytic activity observed. [ABSTRACT FROM AUTHOR]