COLOUR CATCHER®: A VERSATILE SUPPORT FOR SUSTAINABLE PORPHYRIN-BASED TRANSFORMATIONS

Due the wide use of metal porphyrin complexes in catalysis, the development of suitable solid supports is a key step toward more sustainable processes. Heterogenization procedures enable the combination of the high activity and selectivity typical of single-site catalysts with the easy recovery and recyclability of heterogeneous systems. Moreover, the use of naturally derived solid supports can further minimize the economic and environmental impact of synthetic methodologies. In this context, our group has demonstrated that Colour Catcher® is an effective solid support for different porphyrins, yielding materials that can be effectively employed both as sensors and as catalysts. Notably, we recently reported the successful anchoring of a zinc porphyrin, resulting in a low-cost photoactive material capable to activate molecular oxygen under white light, facilitating both the photooxidative coupling of amines and the photooxidation of aldehydes. The chemical features of the employed porphyrin ligand suggested also different applications, provided a change in the coordinated metal. Particularly, considering the reported efficiency of fluorinated iron porphyrins as catalysts for nitrene transfer reactions, we successfully synthesized and anchored the corresponding iron complex onto Colour Catcher®. Preliminary tests on the aziridination of styrenes with aryl azides yielded encouraging results, both under homogeneous and heterogeneous conditions. This protocol appears especially attractive, as it combines the eco-compatibility of iron with that of the Colour Catcher® support.