3,6,13,16-Tetrapropylporphycene: Rational Synthesis, Complexation, and Halogenation

We have designed and synthesized 3,6,13,16-tetrapropylporphycene for the first time as its alkyl analogue from ethyl 4-propyl-1H-pyrrole-2-carboxylate. The substituent effect was found to be more intense than reported positional isomeric tetrapropylporphycenes. The freebase porphycene exhibited moderate fluorescence and complexation ability with divalent metal ions, including Zn(II), which displayed an enhanced emission quantum yield (similar to 30%). The Pd(II) complex and freebase beta-tetrabromoporphycene generated singlet oxygen efficiently (75 and 51%, respectively) and, hence, may find application as potential photosensitizers in photodynamic therapy.

Automated summary

In this study, we successfully designed and synthesized 3,6,13,16-tetrapropylporphycene for the first time as its alkyl analogue. The substituent effect was found to be more intense than previously reported tetrapropylporphycenes, and the compound showed moderate fluorescence and the ability to complex with divalent metal ions. The Pd(II) complex and freebase beta-tetrabromoporphycene exhibited efficient singlet oxygen generation, indicating their potential application as photosensitizers in photodynamic therapy.