Synthesis, spectrco-electrochemical properties and photoreaction with O-2 of lutetium bis-ethyltetraazaporphyrin

The synthesis, spectroscopic and electrochemical properties of the Lu(oepz) (2) (oepz = 2,3,7,8,12,13,17,18-octakis(ethyl)-5, 10,15,20-porphyrazinato) complex are reported. The complex, as inferred from W-vis spectra recorded at different concentrations, strongly aggregates in solution, the most like ly association mode being dimerization. The complex shows a weak near-IR ab sorption (lambda(max) = 834 nm) that is considerably blue-shifted compared with the near-IR absorption of bis(pi-radical) lutetium analogues. The Lu(o epz)(2) neutral species is electrochemically stable between 0.73 and -0.98 V (vs Ag/AgCl), which is the largest range of stability for neutral lutetiu m di- tetrapyrrole complexes. Lu(oepz)(2) shows excellent Type II photodyna mic activity, as indicated by the value of the singlet oxygen generation qu antum yield phi(Delta) of 0.94 obtained by comparison with meso-tetraphenyl porphyrin. (C) 1998 John Wiley & Sons, Ltd.