A comparative study of magnetization dynamics in dinuclear dysprosium complexes featuring bridging chloride or trifluoromethanesulfonate ligands

We utilized a rigid ligand platform PyCp22- (PyCp22- = [2,6-(CH2C5H3)(2)C5H3N](2-)) to isolate dinuclear Dy3+ complexes [(PyCp2)Dy-(mu-O2SOCF3)] 2 (1) and [(PyCp2) Dy-(mu-Cl)](2) (3) as well as the mononuclear complex (PyCp2)Dy(OSO2CF3)(thf) (2). Compounds 1 and 2 are the first examples of organometallic Dy3+ complexes featuring triflate binding. The isolation of compounds 1 and 3 allows us to comparatively evaluate the effects of the bridging anions on the magnetization dynamics of the dinuclear systems. Our investigations show that although the exchange coupling interactions differ for 1 and 3, the dynamic magnetic properties are dominated by relaxation via the first excited state Kramers doublet of the individual Dy sites. Compounds 1 and 3 exhibit barriers to magnetization reversal (U-eff = 49 cm(-1)) that can be favorably compared to those of the previously reported examples of [Cp2Dy(mu-Cl)](2) (U-eff = 26 cm(-1)) and [Cp2Dy(thf)(mu-Cl)](2) (U-eff = 34 cm(-1)).