Harnessing Mechanical Energy: Synthesis of Metal Bipyridine Complexes Via Mechanochemistry

Polypyridyl metal complexes have been extensively investigated in the fields of coordination chemistry and catalysis. 2,2'-Bipyridine is one of the most common and widely explored chelating ligands and has been studied for decades in areas such as medicine, catalysis, batteries, and solar cells. Although metal-bipyridine compounds are widely synthesised in laboratories and industries, green and sustainable approaches to this class of compounds remain unexplored. Mechanochemistry challenges these traditional synthesis routes, promising an environmentally friendly, efficient and rapid approach to the synthesis of organometallic compounds. This work4 describes the mechanosynthesis of several metal-bipyridine complexes based on Ru, Fe, Co, Pd, Pt and Ir, without the need for intense, harsh conditions, complex procedures or bulk solvents. This approach was found to be highly productive compared to conventional solution-based methodologies, as measured by Effective Mass Yield (EMY), E-factor and reaction time. For most of our reactions, we observed optimal EMY and E-factor values, and the reactions were completed in 30 minutes to 1 hour without purification steps. These results highlight the significance of mechanochemistry as a selective and complementary approach to the rapid and environmentally friendly synthesis of organometallics.