Dynamic Magnetic Properties of Germole‐ligated Lanthanide Sandwich Complexes

Abstract

The first germole-ligated single-molecule magnets are reported, with contrasting properties found for the nearlinear sandwich complexes [(η 8 -COT)Ln(η 5 -Cp Ge ] À , where Ln=Dy (1 Dy ) or Er (1 Er ), COT is cyclo-octatetraenyl and Cp Ge is [GeC 4 -2,5-(SiMe 3 ) 2 -3,4-Me 2 ] 2À . Whereas 1 Er has an energy barrier of 120(1) cm À 1 in zero applied field and open hysteresis loops up to 10 K, the relaxation in 1 Dy is characterized by quantum tunneling within the ground state.

Synthesis, Structural Characterization, and Magnetic Properties of Lanthanide Arsolyl Sandwich Complexes

“…This led us to conclude that the low steric demand of the two methyl groups in the 2 and 5 positions of the Tmas ligand combined with the size of the Sm ion itself is the reason for the formation of the dimeric structure. A similar observation was found in the neodymium phospholyl complex [(COT)Nd-(Dsp)(THF)], where, due to the larger ionic radius of the Nd 28 [Er(L Ge )(COT)] − (B), 8 and [Er(L Pb )(COT TIPS )] − (C). 9 The cations of B and C are omitted for clarity.…”

“…Figure 1. Molecular structures of Er-based SMMs with heterocyclopentadienyl ligands [Er(Dsp)(COT)] (A),28 [Er(L Ge )(COT)] − (B),8 and [Er(L Pb )(COT TIPS )] − (C) 9. The cations of B and C are omitted for clarity.…”

Group 14 metallole dianions as η5-coordinating ligands

“…6) was described by the Layfield group in 2023. 39 In this case, the germole-ligated [K(2.2.2-crypt)][(η 5 - 8 )Dy(η 8 -COT)] ( 46 ) and [K(2.2.2-crypt)][(η 5 - 8 )Er(η 8 -COT)] ( 47 ) complexes were synthesized by reacting [K 2 ]8 with [(η 8 -COT)Ln(BH 4 )(thf) 2 ] in 1 : 1 THF and toluene mixture. The Ln–Ct Germole distances are 2.3063(2) ( 46 ) and 2.2693(10) Å ( 47 ).…”

Bimetallic Synergy Enables Silole Insertion into THF and the Synthesis of Erbium Single‐Molecule Magnets

“…Arguably, the most successful general approach to SMM synthesis has focused on pseudo‐two‐coordinate dysprosium metallocene cations, [Dy(η 5 ‐Cp R ) 2 ] + , where Cp R is a bulky cyclopentadienyl ligand such as C 5 i Pr 5 or 1,2,4‐C 5 t Bu 3 H 2 [21–27] . Advances with dysprosocenium SMMs have also stimulated interest in isolobal replacement of cyclopentadienyl ligands with analogues containing heteroatoms such as boron, [28] germanium, [29] lead [30] and phosphorus [31,32] . Significant findings include the borolide‐ligated SMM [{η 5 ‐1‐(piperidino)‐2,3,4,5‐BC 4 Ph 4 } 2 Dy] − , [33] in which the dianionic ligands are thought to induce very strong crystal field splitting at the Dy 3+ centre, leading to a U eff of 1600 cm −1 .…”