Fe₄ Cluster and a Buckled Macrocycle Complex from the Reduction of [(dmgBF₂)₂Fe(L)₂] (L = MeCN, ^<i>t</i>Bu^<i>i</i>NC)

We report the syntheses, X-ray structures, and reductive electrochemistry of the Fe^II complexes [(dmgBF₂)₂Fe­(MeCN)₂] (<b>1</b>; dmg = dimethylglyoxime, MeCN = acetonitrile) and [(dmgBF₂)­Fe­(^<i>t</i>Bu^<i>i</i>NC)₂] (<b>2</b>; ^<i>t</i>Bu^<i>i</i>NC = <i>tert</i>-butylisocyanide). The reaction of <b>1</b> with Na/Hg amalgam led to isolation and the X-ray structure of [(dmgBF₂)₂Fe­(glyIm)] (<b>3</b>; glyIm = glyimine), wherein the (dmgBF₂)₂ macrocyclic frame is bent to accommodate the binding of a bidentate apical ligand. We also report the X-ray structure of a rare mixed-valence Fe₄ cluster with supporting dmg-type ligands. In the structure of [(dmg₂BF₂)₃Fe₃(¹/₂dmg)₃Fe­(O)₆] (<b>4</b>), the (dmgBF₂)₂ macrocycle has been cleaved, eliminating BF₂ groups. Density functional theory calculations and electron paramagnetic resonance data are in accordance with a central Fe^III ion surrounded by three formally Fe^IIdmg₂BF₂ units