Pyrrole dicarboxylate substituted porphyrazine, microwave assisted synthesis and properties

In this study, a new magnesium(II) porphyrazine derivative tetrasubstituted with dicarboxypyrrolyl moieties was synthesized. Two different approaches were used, utilizing conventional heating and microwave irradiation. The developed three-step processes were compared showing the superior performance of the microwave-assisted organic synthesis. The new macrocycle and the novel maleonitrile derivatives were characterized using spectral techniques (mass spectrometry, NMR spectroscopy, UV-Vis spectrophotometry) and the ability of the porphyrazine to generate singlet oxygen assessed using the method with 1,3-diphenylisobenzofuran. The singlet oxygen generation quantum yields were found to be moderate (Φ_Δ = 0.23 and 0.22 in DMF and DMSO, respectively) and no aggregation behavior was noted in a series of dilutions. Additionally, the acute toxicity test using Microtox was performed showing almost no toxicity at the concentration of 10^{- 5} mol/L. The electrochemical studies revealed three redox processes of targeted porphyrazine with low first oxidation peak, whereas the spectroelectrochemistry showed the formation of both cationic and anionic species at proper potentials.