Zero‐field Slow Magnetic Relaxation Behavior of Dy₂ in a Series of Dinuclear {Ln₂} (Ln=Dy, Tb, Gd and Er) Complexes: A Combined Experimental and Theoretical Study

Abstract

A series of dinuclear lanthanide(III) complexes having general formulae [Ln2L2(thd)4] ⋅ 2CH3CN {Ln=DyIII(1), TbIII(2), GdIII(3), ErIII(4)} were successfully synthesized using Schiff base (E)‐2‐((pyridin‐2‐ylmethylene)amino)phenol (LH) and co‐ligand 2,2,6,6‐Tetramethyl‐3,5‐heptanedione (Hthd). The single crystal XRD data shows that complexes possess a dinuclear planar [Ln2(μ2‐O)2]4+ core where phenolate oxygen atoms act as bridges between the two LnIII ions, and that the coordination sphere of LnIII with eight coordination has distorted trigonal dodecahedron geometry. The magnetic analysis shows complex 1 is a single molecule magnet having a zero‐field effective energy barrier (Ueff) of 54.02 K and relaxation time of τo=4.45×10−6 s. Field‐induced SMM behavior has been observed for 4 with an effective energy barrier of 26.9 K and τ0=2.4×10−9 s. CASSCF+RASSI‐SO calculations on 1, 2 and 4 provide deep insight regarding the electronic structure and single‐ion anisotropy of lanthanide ions. Further, using state‐of‐the‐art ab initio calculations, the nature of magnetic anisotropy and magnetic exchange interaction between the LnIII centers is analyzed to shed light on the magnetic dynamics of all the complexes 1–4.

Magnetocaloric effect and slow magnetic relaxation in peroxide-assisted tetranuclear lanthanide assemblies

“…Previous magneto-structural correlation studies suggest that a large ∠Gd-O-Gd bond angle (>110°) often results in a weak ferromagnetic exchange. 128,[135][136][137][138] For the J 1 interaction, the ∠Gd-O-Gd bond angles for the μ 2 -O bridge are ∼108°and 105°/100°(avg. ∼102.5°) for the η 2 -bridged peroxo ligand.…”

Ferromagnetically coupled CoII2LnIII2 complexes (where LnIII = Ho, Er, Yb): experimental and theoretical investigations

“…54,55 BS-DFT calculations have been routinely used to study the magnetic exchange interaction for 3d-4f and 4f-4f complexes. [56][57][58][59][60][61] For our calculations, the anisotropic centers of Ho III and Yb III in complexes 1 and 3 were substituted with the isotropic counterpart of Gd III . The details of calculations are provided in the ESI.…”

Interplay between anisotropy and magnetic exchange to modulate the magnetic relaxation behaviours of phenoxo bridged Dy2dimers with axial β-diketonate co-ligands

“…This methodology has been widely used to extract SH parameters in various lanthanide/actinide complexes. 40,[109][110][111][112][113][114][115][116] The details of the computational methodology are provided in the ESI. † The overall energy spectrum, g-tensors, the angle between the anisotropy axis of the ground state and the first excited state doublet (Φ), and the angle between the ground state anisotropy axis, arising from the eight Kramers' doublets (KDs) pertinent to the splitting of the ground 6 H 15/2 spin-orbit ground atomic term in complexes 1-3, have been collated in Table 2 and Tables S9-S11.…”