Self-assembled binary structures of Fe(III) and metal-free porphyrins for solar light-assisted catalytic hydrogenation of 4-nitrophenol

Eco-sustainable reduction reactions using nontoxic and non-noble metal-based materials can be inspired on biomimetic catalysis although their development remains a challenge. In this work, nanostructured materials carrying Fe(III) porphyrins have been prepared by ionic self-assembly in water and tested in the mimics of the six electron reduction activity of nitrite reductase, in the presence of NaBH4. A structuring effect is observed in solar light-assisted conditions. For materials built with two oppositely charged Fe(III) porphyrins, the increase in catalytic activity was temperature-dependent, whereas in a material built with a metal-free porphyrin and a Fe(III) porphyrin, the activity was dependent on visible-light irradiation. This latter material shows the highest catalytic activity after an induction time, with K1 = 388 min−1·g−1 and a good performance after reuse studies.