A Cyclic {Ni$^{II}$$_8$Dy$^{III}$$_4$} Cluster Where the Dy$^{III}$ Moments Are Organized by the Transition Metal Spins

A series of [Ni$_8$Ln$_4$(CO$_3$)$_4$(L)$_8$(NO$_3$)$_2$(H$_2$O)$_8$ (MeOH)$_4$](NO$_3$)$_2$ (Ln = Dy (1), Gd (2), Y (3)) cyclic coordination clusters containing four carbonate bridges were isolated and studied using SQUID and microSQUID experiments and quantum mechanical calculations. The dodecanuclear Ni$_8$Dy$_4$ complex exhibits slow relaxation of the magnetization confirmed by the presence of temperature- and field-dependent magnetic hysteresis loops. The competing interactions and the anisotropic nature within the cluster were analyzed using DFT and ab initio calculations and revealed that the spin structure of the DyIII ions is steered by the interactions mediated through the NiII ions.