Dominance of Cyclobutadienyl Over Cyclopentadienyl in the Crystal Field Splitting in Dysprosium Single‐Molecule Magnets

• DOI: 10.1002/ange.202200525
• Publication Date: 2022-02-02T18:10:44Z
• Authors: James P. Durrant; Benjamin M. Day; Jinkui Tang; Akseli Mansikkamäki; Richard A. Layfield
• Keywords: Dysprosium; Cyclopentadienyl complex; Molecular magnets

Abstract Replacing a monoanionic cyclopentadienyl (Cp) ligand in dysprosium single‐molecule magnets (SMMs) with dianionic cyclobutadienyl (Cb) the sandwich complexes [(η 4 ‐Cb′′′′)Dy(η 5 ‐C Me t Bu)(BH )] − ( 1 ), 8 ‐Pn † )K(THF)] 2 ) and 3 leads to larger energy barriers magnetization reversal (Cb′′′′=C (SiMe , Pn =1,4‐di(tri‐isopropylsilyl)pentalenyl). Short distances Cb′′′′ ligands longer Cp – are consistent crystal field splitting being dominated by former. Theoretical analysis shows that magnetic axes ground Kramers doublets of oriented towards ligands. The theoretical axiality parameter relative Z rel introduced facilitate comparisons SMM performance benchmark SMM. Increases when Cb′′′ replaces signposts route SMMs properties could surpass leading systems.