A new family of hetero-tri-metallic complexes [M(CuTb)]n (n=1, 2, ∞; M = Co, Cr, Fe): synthesis, structure and tailored single-molecule magnet behavior

A new family of hetero-tri-metallic complexes [M(CuTb)](n) (M-III = Co, Cr, Fe; n = 1, 2, infinity), composed of three series of three compounds (oligo-and poly-nuclear complexes based on [Cu-Tb] subunits), is presented and fully characterized. These nine compounds, viewed as different assemblies of single-molecule magnet (SMM) building blocks, connected to various hexacyanometalate centers, illustrate how the SMM behavior of the [CuTb] moiety can be modulated via the control of intermolecular interactions. Specifically, the combination of the non-innocent diamagnetic [Co-III(CN)(6)](3-) center with a [Cu-Tb](3+) moiety enabled isolation of the magnetic entities, resulting in an improvement of the SMM behavior (ranging from U-eff = 5-7 cm(-1) to 15-17 cm(-1)).