The versatility of gold: From heterogeneous catalysis to biomedicine

This mini-review is to commemorate prof. Renato Ugo introducing a brief overview of our research on gold conducted in the same department at Milan University where he worked as a beloved professor of Inorganic Chemistry and eminent scientist. The aim is to provide a short outline of our main contributions to gold-based heterogeneous catalysis with a look at biomedicine. Gold nanoparticles, alone or alloyed with a second metal, displayed superior performance in the selective aerobic oxidation of a variety of alcohols and aldehydes than the conventional palladium and platinum catalysts, both in liquid and gaseous phase. Whereas supporting nanometric gold on different oxides or carbons allowed to retain its stability and durability over time, the extraordinary properties of colloidal “naked” gold clearly emerged and are herein discussed. In particular, the molecular mechanism underlying the aerobic oxidation of glucose with gold catalysis was disentangled by kinetic studies. Gold has been successfully employed even in glycerol valorisation as well as in the catalytic polymerization of aniline, thus offering an eco-friendly alternative route to conventional polluting syntheses. The way from the discovery to the commercialization of gold-based catalysts has been long and paved with success but even obstacles. Only recently gold catalysis has finally found its first large-scale application in the chemical industry, thus showing how the ‘yellow metal’ is more than a promise. Last but not least, gold nanoparticles are elective candidates for cancer therapy. On this regard, we have developed a simple approach for the synthesis of extra-small gold nanoparticles to be potentially employed in breast cancer treatment. This adds another gusset to the versatility of the once-considered inert metal.