Dynamic magnetic properties of germole-ligated lanthanide sandwich complexes

The first germole-ligated single-molecule magnets are reported, with contrasting properties found for the near-linear sandwich complexes [(?8-COT)Ln(?5-CpGe]-, where Ln = Dy (1Dy) or Er (1Er), COT is cyclo-octatetraenyl and CpGe is [GeC4-2,5-(SiMe3)2-3,4-Me2]2-. Whereas 1Er has an energy barrier of 120(1) cm-1 in zero applied field and open hysteresis loops up to 10 K, the relaxation in 1Dy is characterized by quantum tunneling within the ground state.