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

Thermolysis of a 1:1:1 mixture of Me LH ( Me L = {(2,6- i Pr 2 C 6 H 3 )NC(Me)} 2 CH), N -hydroxyphthalimide (HOPth), and diethylzinc in toluene at 77 °C provided [ Me LZn(OPth)] ( 1 ) in good yield after workup. The subsequent reduction of 1 with 1.3 equiv of KC 8 and 1 equiv of 2.2.2-cryptand, in tetrahydrofuran, provided [K(2.2.2-cryptand)][ Me LZn(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.