Enhanced single-molecule magnetism in dysprosium complexes of a pristine cyclobutadienyl ligand.

James P Durrant,Jinkui Tang,Richard A Layfield,Akseli Mansikkamäki

doi:10.1039/d0cc01722a

Abstract

Intact transfer of the cyclobutadienyl ligand [C4(SiMe3)4]2- to yttrium and dysprosium (M) produces the half-sandwich complexes [M{η4-C4(SiMe3)4}(BH4)2(THF)]- as coordination polymers with bridging sodium or potassium ions. The dysprosium versions are single-molecule magnets (SMMs) with energy barriers of 371(7) and 357(4) cm-1, respectively. The pristine cyclobutadienyl ligands provide a strong axial crystal field that enhances the SMM properties relative to related cyclopentadienyl compounds.

Highlights

Intact transfer of the cyclobutadienyl ligand [C4(SiMe3)4]2À to yttrium and dysprosium (M) produces the half-sandwich complexes [M{g4-C4(SiMe3)4}(BH4)2(THF)]À as coordination polymers with bridging sodium or potassium ions
single-molecule magnets (SMMs) based on lanthanides dominate the landscape,[2,3] with terbium and dysprosium being the most popular owing to the strong spin–orbit coupling and magnetic anisotropy of Tb3+ and Dy3+ ions, which are required to observe magnetic hysteresis
The structure of 1Dy consists of an asymmetric unit in which two similar yet crystallographically unique half-sandwich units alternate along zigzag polymeric chains (Fig. 1)

Summary

Introduction

Intact transfer of the cyclobutadienyl ligand [C4(SiMe3)4]2À to yttrium and dysprosium (M) produces the half-sandwich complexes [M{g4-C4(SiMe3)4}(BH4)2(THF)]À as coordination polymers with bridging sodium or potassium ions. The pristine cyclobutadienyl ligands provide a strong axial crystal field that enhances the SMM properties relative to related cyclopentadienyl compounds.

Results

Conclusion