Characterisation of iron tetraarylporphyrins co-ordinatively bound to solid supports

Abstract

Iron(III) tetra(pentafluorophenyl)- and tetra(2,6-dichlorophenyl)-porphyrin (FeTPFPP and FeTDCPP) have been co-ordinatively bound to imidazole and pyridine groups on organic polymers (PSIm and PVP) and on the surface of silica (Silm and SiPy). The oxidation and spin states of the resulting supported catalysts have been characterised by UV–VIS, resonance Raman and EPR spectroscopy. Evidence is presented that the iron porphyries on the flexible organic polymers are all low-spin bis-ligated iron(II) species. In contrast, on the rigid modified silicas the iron porphyries are mono-ligated and high spin. Furthermore whereas FeTDCPP on Sum is an iron(III) species, on SiPy it is iron(II) and FeTPFPP on SiIm is a mixture of both oxidation states.