Structural and Spectroscopic Characterization of a Zinc-Bound N‑Oxyphthalimide Radical

Thermolysis of a 1:1:1 mixture of MeLH (MeL = {(2,6-iPr2C6H3)­NC­(Me)}2CH), N-hydroxyphthalimide (HOPth), and diethylzinc in toluene at 77 °C provided [MeLZn­(OPth)] (1) in good yield after workup. The subsequent reduction of 1 with 1.3 equiv of KC8 and 1 equiv of 2.2.2-cryptand, in tetrahydrofuran, provided [K­(2.2.2-cryptand)]­[MeLZn­(OPth)] (2) in 74% yield after workup. Characterization of 2 via X-ray crystallography and electron paramagnetic resonance spectroscopy reveals the presence of an S = 1/2 radical on the N-oxyphthalimide ligand. Importantly, these data represent the first structural and spectroscopic confirmation of the redox activity of a metal-bound N-oxyphthalimide fragment, expanding the range of structurally characterized redox-active ligands.