Photolysis of Pincer-Ligated PdII–Me Complexes in the Presence of Molecular Oxygen

The reactions of t‑BuPNP and t‑BuPCP PdII–Me complexes (t‑BuPNP = 2,6-bis­[(di-tert-butylphosphino)­methyl]­pyridine and t‑BuPCP = 2,6-bis­[(di-tert-butylphosphino)­methyl]­phenyl) with O2 are described and compared with the reported O2 reactivity of related PdII–Me complexes. [(t‑BuPNP)­PdMe]Cl was found to react with O2 upon photolysis resulting in oxidation of the pincer ligand backbone to produce a (t‑BuPNO)­PdCl complex. In contrast, photolysis of (t‑BuPCP)­PdMe with O2 resulted in oxidation of the Pd–Me group to form (t‑BuPCP)­PdOCO2H. Isotopic labeling, radical initiators, and solvent studies were used to gain insight into the mechanisms of these unusual reactions of late metal alkyls with molecular oxygen.