Single-Molecule Magnets Constructed from Cyanometalates: {[Tp*FeIII(CN)3MII(DMF)4]2[OTf]2}·2DMF (MII = Co, Ni)

Treatment of several divalent transition-metal trifluoromethanesulfonates [MII(OTf)2; MII = Mn, Co, Ni] with [NEt4][Tp*FeIII(CN)3] [Tp* = hydridotris(3,5dimethylpyrazol-1-yl)borate] in DMF affords three isostructural rectangular clusters of {[Tp*FeIII(CN)3MII(DMF)4]2[OTf]2}·2DMF (MII = Mn, 3; Co, 4; Ni, 5) stoichiometry. Magnetic studies of 3-5 indicate that the Tp*Fe(CN)3- centers are highly anisotropic and exhibit antiferromagnetic (3 and 4) and ferromagnetic (5) exchange to afford S = 4, 2, and 3 spin ground states, respectively. ac susceptibility measurements suggest that 4 and 5 exhibit incipient single-molecule magnetic behavior below 2 K.