UV–visible, fluorescence and EPR properties of porphyrins and metalloporphyrins

In order to search for novel luminescent and EPR oximetry materials, a series of porphyrins and metalloporphyrins with different peripheral substitutes and central transition metal ions were synthesized and their UV–vis, fluorescence and EPR spectra were studied. It was found that variations in the peripheral substituents imparted no change to the UV–vis spectra in the case of metal-free porphyrins. However, differences in the central transition metal ions resulted in changes in the energy of electron transitions which caused changes in UV–vis spectra. Variations in the peripheral substituents and the central metal ions influenced both the fluorescence and EPR spectra.