Inter–multiplet Transitions in the Fe4 Magnetic Cluster

The tetrairon(III) clusters Fe4(L)2(dpm)6 where Hdpm = dipivaloylmethane and H3L = MeC(CH2OH)3 or PhC(CH2OH)3 were obtained by site-specific replacement of the six methoxide bridges in Fe4(OMe)6(dpm)6. As compared with the parent compd., the new clusters show a much larger anisotropy in the S = 5 ground spin state (D/kB∼-0.6 K vs. -0.3 K) and a higher energy barrier to the reversal of the magnetization.