Redox characteristics of a lead(II) complex supported by a o -phenylenediamido ligand

A lead(II) complex coordinated by a sterically demanding o-phenylenediamido ligand is synthesized. The ligand is redox-active to reach the diiminobenzosemiquinone radical anion state. This state is generated by an electrochemical method or a chemical oxidation using AgOTf, but the oxidation number of the central metal is not changed. In the presence of toly-sulfonyl lazides (Tol-N3), the chemical oxidation of the lead(II) complex at −80 °C gives the nitrene-radical-bound lead(II) complex, which also contains the diiminobenzosemiquinone ligand. Kinetic studies on the generation of the nitrene-radical-bound complexes reveal that the rate-determining step involves a binding step of the tolyl-sulfonyl azide to the lead(II) center or a N2 elimination step from the azide-bound complex. The rate-determining step is controlled by changing the substituent of the tolyl-sulfonyl azide.