Determination of spin and orbital moments of Re(I) in the molecular nanomagnet [Er(ReCp2)3] and its Gd analog

The target of this proposal is X-ray Absorption Near Edge Structure (XANES) and X-ray Magnetic Circular Dichroism (XMCD) of crystalline samples of two intermetallic molecules [Ln(ReCp2)3] (Ln = Er,[1] or Gd; Cp = cyclopentadienyl) where the paramagnetic trivalent Ln is coordinated only by the “formally diamagnetic” monovalent Re ions via metal-metal bonds. The experiments will enable the determination of the induced spin and orbital moments of Re and their contributions in the magnetic interaction pathways for these molecules. The structure of [Ln(ReCp2)3] is made of Ln centers coordinated by three [ReCp2]- complexes, where the oxidation state is assumed based on the magnetic behavior of the [Er(ReCp2)3] analog. The magnetic properties of [Er(ReCp2)3] indicate ferromagnetic intermolecular interactions. The element-selective study of this family (XANES and XMCD at the L2,3-edges of Re and the rare-earths) is necessary to understand the origin of their magnetic properties.