Fe_4 Cluster and a Buckled Macrocycle Complex from the Reduction of [(dmgBF_2)_(2)Fe(L)_2] (L = MeCN, ^(t)Bu^(i)NC)

We report the syntheses, X-ray structures, and reductive electrochemistry of the Fe^(II) complexes [(dmgBF_2)_(2)Fe(MeCN)_2] (1; dmg = dimethylglyoxime, MeCN = acetonitrile) and [(dmgBF_2)Fe(^(t)Bu^(i)NC)_2] (2; ^(t)Bu^(i)NC = tert-butylisocyanide). The reaction of 1 with Na/Hg amalgam led to isolation and the X-ray structure of [(dmgBF_2)_(2)Fe(glyIm)] (3; glyIm = glyimine), wherein the (dmgBF_2)_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 [(dmg_(2)BF_2)_(3)Fe_3(1/2dmg)_(3)Fe(O)_6] (4), the (dmgBF_(2))_2 macrocycle has been cleaved, eliminating BF_2 groups. Density functional theory calculations and electron paramagnetic resonance data are in accordance with a central FeIII ion surrounded by three formally Fe^(II)dmg_(2)BF_2 units