Pentametallic lanthanide-alkoxide square-based pyramids: high energy barrier for thermal relaxation in a holmium single molecule magnet

Abstract

Pentametallic Ln complexes of formula [Ln(5)O(O(i)Pr)(13)] have been made, where Ln(III) = Sm, Gd, Tb, Ho and Er; slow magnetisation relaxation to 33 K is observed for the Ho complex with an energy barrier of ca. 400 K.

Molecular single-ion magnets based on lanthanides and actinides: Design considerations and new advances in the context of quantum technologies

“…The isostructural Ho analogue of 3, [Ho5O(O i Pr)13] (7), showed slow magnetic relaxation to 30 K [66]. Despite possessing an energy barrier to relaxation of 400 K (an order of magnitude higher than any other holmium single molecule magnet), and a highly axial magnetic structure, the large tunnel splittings associated to the ground doublet ), the Dy 3+ ion adopts a pseudooctahedral geometry, being coordinated by two tridentate carbene ligands that place two dianionic carbon donors along the z-axis and four neutral nitrogen donors in the xy plane of the coordination sphere (Fig.…”

“…The loop width generally increases with a decrease of temperature and with an increase of the field-charging rate [32]. The most used method for detecting and characterising slow magnetic relaxation is through the use of alternating current (ac) magnetic susceptibility measurements [65][66][67][68][69][70]. Wherein, a small oscillating magnetic field is applied to the sample, and the in-phase and out-of-phase components of magnetic susceptibility are measured over a range of temperatures, oscillation frequencies, and static magnetic fields.…”

Molecular Nanomagnets and Related Phenomena

“…There are now compounds of Tb phthalocyanine compounds with U eff > 900 K [397]; Dy compounds with U eff > 800 K [389]; Ho compounds with U eff % 400 K [398]; Er compounds with U eff > 300 K [399]. There are now compounds of Tb phthalocyanine compounds with U eff > 900 K [397]; Dy compounds with U eff > 800 K [389]; Ho compounds with U eff % 400 K [398]; Er compounds with U eff > 300 K [399].…”

Coordination‐Cluster‐Based Molecular Magnetic Refrigerants

“…Shortly afterwards, a isopropoxide‐bridged pentametallic Ln square‐based pyramid (Figure ), 22 , was synthesized by Winpenny et al41 The Gd III ions in 22 are six‐coordinate octahedra and occupy the vertices of a regular square‐based pyramid, but the Gd III ions shift towards the terminal alkoxide and away from the central μ 5 ‐oxide. The magnetic susceptibility measurements reveal an intramolecular antiferromagnetic interaction with a frustrated J =0.085 cm −1 .…”