Disclosed herein are reaction compositions comprising an oxidation catalyst, a solvent, and a substrate that is dissolved in the solvent. The oxidation catalyst comprises a metal ion complexed with an α-keto acid and a tridentate N,N,O-ligand. Also disclosed herein are methods for oxidizing a C-H bond of a molecule, the methods comprising contacting the molecule with a metal complex comprising a metal ion complexed with a tridentate N,N,O-ligand in the presence of an α-keto acid and a solvent. In some embodiments, the oxidation catalyst or metal complex is linked to a solid support.