Synthesis, Characterization, and Reversible Multielectron Redox Properties of a Biradical Yttrium Complex Containing Bis(2‐isopropylaminophenyl)amide

The redox‐active ligand bis(2‐isopropylaminophenyl)amide (NNN) was used to prepare ionic yttrium complex [(NNNsq·)2Y]–[Li(thf)4]+ (2; sq = semiquinonate form). A solid‐state magnetic measurement on 2 (µeff = 2.40 µB) indicated the presence of two unpaired electrons on two separate NNN ligands. The paramagnetic compound 2 was characterized by EPR spectroscopy in a dilute frozen solution of thf, which suggested there was no intramolecular radical–radical interaction. Electrochemistry of 2 featured a quasireversible two‐electron reduction process at –1.193 V attributed to the 22–/2 redox couple, and two successive one‐electron oxidation processes at –0.406 V and –0.156 V attributed to the reversible 2/2+ redox couple and quasireversible 2+/22+ redox couple, respectively. Redox‐active ligand bis(2‐isopropylaminophenyl)amide afforded an ionic yttrium complex. This scarce example of a mononuclear biradical rare earth metal complex features reversible and quasireversible multielectron redox behavior in electrochemistry.