Ullmann reaction through ecocatalysis: insights from bioresource and synthetic potential

International audienceWe report the elaboration of novel bio-sourced ecocatalysts for Ullmann coupling reaction. Ecocatalysis is based on the recycling of metals issued from phytoremediation or rehabilitation, and an innovative chemical valorization of the subsequent biomass in the field of catalysis. Here, we describe the efficient copper accumulation by plants via phytoextraction and rhizofiltration. These phytotechnologies were revisited to demonstrate a novel potential of these natural resources for the Green Chemistry. Taking advantage of the remarkable ability of the selected plants to accumulate Cu(II) species into their roots or leaves, these latter can be directly used for the preparation of ecocatalysts, called Eco-Cu ®. The formed Eco-Cu ® catalysts are thoroughly characterized via ICP-MS, IR study of pyridine sorption/desorption, TEM, XRD, SM and model reactions, in order to elucidate the chemical composition and catalytic activity of these new materials. Significant differences of properties and activities were observed between Eco-Cu ® and conventional Cu catalysts. Eco-Cu ® appear as highly active catalysts in Ullmann coupling reactions with lower Cu quantity compared to known copper catalysts