The spectral and luminescent properties of new complexes of lutetium(III)–chloride with 5,10,15,20-tetraphenylporphine and its mono-nitrophenyl derivative with a para-nitro group on one of the meso-phenyl rings were studied. The complexes showed weak fluorescence (φfl = 5·10–4) and moderate phosphorescence (φphosph = 3·10–2) at 77 K and phosphorescence at room temperature. The type of extra ligand (monodentate chloride and bidentate acetylacetonate) and the presence of an electron-withdrawing NO2 group on the meso-phenyl ring did not have an appreciable effect on the photophysics of the Lu(III)-porphyrins. The phosphorescence spectra of the complexes were shifted to the long-wavelength region. The phosphorescence lifetimes were longer (2800–3100 μs) than those of the known oxygen sensors Pt(II)- or Pd(II)-porphyrins. The oxygen determination limit in solution was estimated from quenching of the Lu(III)-porphyrin phosphorescence.
