Synthesis and spectroscopic characterization of Ni, Zn, Pd and Pt tetra(pentafluorophenyl)porpholactone with comparisons to Mg, Zn, Y, Pd and Pt metal complexes of tetra(pentafluorophenyl)porphine

Ni, Zn, Pd and Pt tetra(pentafluorophenyl)porpholactone (TFPL) were synthesized and identified by their optical and mass spectra. The lactone ring was produced from the parent free-base porphyrin using silver nitrate and oxalic acid with a yield of 73%, and the metals were inserted by standard procedures from metal salts. The compounds show intense Soret Bands in the region 390-420 nm. The longest wavelength visible absorbance peaks, in the region 572-608 nm, are weaker than the Soret peaks by a factor of only similar to3 for the Ni, Pd, and Pt complexes but a factor of similar to10 for the free-base and Zn complexes. As found with other metalloporphyrins the Ni complex is dark, Zn shows fluorescence and Pd and Pt complexes show strong phosphorescence. The Pd complex also shows a weak fluorescence not quenched by oxygen. The phosphorescence lifetimes of Pd and Pt complexes of TFPL in 3-methylpentane at 77 K are, respectively, similar to1 ms and similar to70 mus, about 60% that of the TFPP complexes. The wavelengths of phosphorescence emission, 733 nm and 758 nm for PtTFPL and PdTFPL, respectively, are sufficiently red-shifted so that these pressure sensitive luminophors can be included in the same pressure sensitive paint (PSP) as Eu complexes, whose emission at similar to615 nm can serve as a temperature sensor. The fluorescences of Mg, Zn, and Y(TFPP) show weak origin bands, making them suitable as unquenched references for PSR Copyright (C) 2002 Society of Porphyrins & Phthalocyanines.