Fe4 Cluster and a Buckled Macrocycle Complex from the Reduction of [(dmgBF2)2Fe(L)2] (L = MeCN, tBuiNC)

We report the syntheses, X-ray structures, and reductive electrochemistry of the FeII complexes [(dmgBF2)2Fe­(MeCN)2] (1; dmg = dimethylglyoxime, MeCN = acetonitrile) and [(dmgBF2)­Fe­(tBuiNC)2] (2; tBuiNC = tert-butylisocyanide). The reaction of 1 with Na/Hg amalgam led to isolation and the X-ray structure of [(dmgBF2)2Fe­(glyIm)] (3; 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] (4), 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 FeIII ion surrounded by three formally FeIIdmg2BF2 units.