Ferromagnetic Exchange and Slow Magnetic Relaxation in Cobalt Bis(1,2-dithiolene)-Bridged Dilanthanide Complexes.

The construction of multinuclear lanthanide-based molecules with significant magnetic exchange interactions represents a key challenge in the realization of single-molecule magnets with high operating temperatures. Here, we report the synthesis and magnetic characterization of two series of heterobimetallic compounds, (Cp*Ln)(μ-Co(pdt)) (Ln = Y, Gd, Dy; pdt = 1,2-diphenylethylenedithiolate) and [K(18-crown-6)][(Cp*Ln)(μ-Co(pdt))] (Ln = Y, Gd), featuring two lanthanide centers bridged by a cobalt bis(1,2-dithiolene) complex. Dc magnetic susceptibility data collected for the Gd congeners indicate significant Gd-Co ferromagnetic exchange interactions with fits affording = +11.

Linear Inverse Sandwich Complexes of Tetraanionic Benzene Stabilized by Covalent δ-Bonding with Late Lanthanides.

A series of dilanthanide benzene inverse sandwich complexes of the type (CpLn)(μ-η:η-CH) () (Ln = Y, Gd, Tb, Dy, Tm) are reported. These compounds are synthesized by reduction of the respective trivalent dimers CpLnI (Ln = Y, Gd, Tb, Dy, Tm) in diethyl ether with potassium graphite in the presence of benzene, and they feature an unusual linear coordination geometry with a highly planar benzene bridge as verified by single-crystal X-ray diffraction. The Ln-Bz distances of are the shortest distances observed to date, ranging from 1.

Strong Axiality in a Dysprosium(III) Bis(borolide) Complex Leads to Magnetic Blocking at 65 K.

Substituted dysprosocenium complexes of the type [Dy(Cp)] exhibit slow magnetic relaxation at cryogenic temperatures and have emerged as top-performing single-molecule magnets. The remarkable properties of these compounds derive in part from the strong axial ligand field afforded by the cyclopentadiene anions, and the design of analogous compounds with even stronger ligand fields is one promising route toward identifying new single-molecule magnets that retain a magnetic memory at even higher temperatures. Here, we report the synthesis and characterization of a dysprosium bis(borolide) compound, [K(18-crown-6)][Dy(BCPh)] (), featuring the dysprosocenate anion [Dy(BCPh)] with a pseudoaxial coordination environment afforded by two dianionic pentaphenyl borolide ligands.