Electrochemical Ammonia Oxidation Catalyzed by Ruthenium Complexes Bearing 4,4’-Substituted Bipyridine Dicarboxylate Ligands

We have examined electrochemical ammonia oxidation catalyzed by ruthenium complexes bearing 4,4’-substituted 2,2’-bipyridine-6,6’-dicarboxylate (bda) ligands and axial isoquinoline ligands. Bulk electrolysis revealed that a ruthenium complex bearing 4,4’-dimethyl substituted bda ligand showed a slightly higher catalytic activity than that bearing an unsubstituted ligand likely due to the enhanced stability of the complex, whereas a complex bearing 4,4’-bis(trifluoromethyl) substituted bda ligand showed much lower catalytic activity.