Synthesis, Spectroscopy and Electrochemistry of Lanthanide bis-(ethylsulfanyl) tetraazaporphyrins

Reaction of the oespz(2-) ligand (oespz = 2,3,7,8,12,13,17,18-octakis (ethylsulfanyl)-5, 10,15,20-porphyrazinato) with trivalent lanthanide ions, such as Nd3+, Eu3+, Dy3+, Yb3+ and Lu3+, leads to the direct synthesis of the corresponding sandwich complexes, in the radical, ligand-oxidized green form, whereas the reaction with La3+ affords the sandwich complex in the protonated, blue form. It is found that the ligand-oxidized complexes show rather weak electronic absorptions in the range 850-1150 nm and are, compared to lanthanide diporphyrins and diphthalocyanines, very stable both to oxidation and to reduction.