Enhancing blocking temperature (TB) is one of the holy grails in Single Molecule Magnets(SMMs), as any future potential application in this class of molecules is directly correlated to this parameter....

The recently reported compound [Dy III LF](CF 3 SO 3 ) 2 ·H 2 O (L = 1,4,7,10-tetrakis(2-pyridylmethyl)-1,4,7,10-tetraaza-cyclododecane) displays a strong axial magnetic anisotropy, due to the short axial Dy–F bond, and single-molecule magnet (SMM) behavior. Following our earlier [Dy III LF] 2+ work, herein we report the systematic structural and magnetic study of a family of [Ln III LF](CF 3 SO 3 ) 2 ·H 2 O compounds (Ln(III) = 1 -Ce, 2 -Pr, 3 -Nd, 4 -Eu, 5 -Tb, 6 -Ho, 7 -Er, 8 -Tm, and 9 -Yb). From this series, the Ce(III) and Nd(III) analogues show slow relaxation of the magnetization under an applied direct current magnetic field, which is modeled using a Raman process. Complete active space self-consistent field theoretical calculations are employed to understand the relaxation pathways in 1 -Ce and 3 -Nd and also reveal a large tunnel splitting for 5 -Tb. Additional computational studies on model compounds where we remove the axial F – ligand, or replace F – with I – , highlight the importance of the F – ligand in creating a strong axial crystal field for 1 -Ce and 3 -Nd and for promoting the SMM behavior. Importantly, this systematic study provides insight into the magnetic properties of these lighter lanthanide ions.

The mechanistic investigations between Cu(II) and the anisotropic lanthanides (Ln(III)) are not much explored to date. This is due to the complicated energy spectrum which arises due to the orbital angular momentum of anisotropic lanthanides. Interestingly, the exchange coupling J in Ln(III)−Cu(II) systems was found to be antiferromagnetic for <4f 7 metal ions and ferromagnetic for ≥4f 7 metal ions, while the net magnitude of J Total strength gradually decreases moving from f 1 to f 13 . While this is established in several examples, the reason for this intriguing trend is not rationalized. In this article, we have taken up these challenging tasks by synthesizing a family of complexes with the general molecular formula [Cu 2 Ln(HL) 4 (NO 3 )](NO 3 ) 2 , where Ln = La (1 -La ), Ce (2 -Ce ), Pr (3 -Pr ), Gd (4 -Gd ), Tb (5 -Tb ), Dy (6 -Dy ), and Ho (7 -Ho ) and HL = C 15 H 15 N 1 O 3 ; (2methoxy-6-[(E)-2′-hydroxymethyl-phenyliminomethyl]-phenolate) is a monodeprotonated tridentate Schiff base ligand. Detailed dc magnetic susceptibility measurements performed for all the complexes reveal that the Cu(II) ion is coupled ferromagnetically to the respective Ln(III) ion, which has more than seven electrons in the 4f shell, while an antiferromagnetic coupling is witnessed if Ln(III) has less than seven electrons. The strength of the exchange coupling constant was quantitatively determined for representative complexes from the high-field/high-frequency electron paramagnetic resonance spectroscopy which follows the order of 4 -Gd (1.50(10) cm −1 ) > 5 -Tb (1.18(10) cm −1 ) > 6 -Dy (0.56(10) cm −1 based on the −

Lanthanide based Single molecular magnets (SMMs), particularly Dysprocenium based SIMs, are well known for their high energy barrier for spin reversal (Ueff) and blocking temperatures (TB). Enhancing these two parameters...

The present work is part of our ongoing quest for developing functional inorganic complexes using unorthodox pyridyl–pyrazolyl-based ligands. Accordingly, we report herein the synthesis, characterization, and luminescence and magnetic properties of four 3d–4f mixed-metal complexes with a general core of Ln2Zn6 (Ln = Dy, Gd, Tb, and Eu). In stark contrast to the popular wisdom of using a compartmental ligand with separate islands of hard and soft coordinating sites for selective coordination, we have vindicated our approach of using a ligand with overcrowded N-coordinating sites that show equal efficiency with both 4f and 3d metals toward multinuclear cage-cluster formation. The encouraging red and green photolumiscent features of noncytotoxic Eu2Zn6 and Tb2Zn6 complexes along with their existence in nanoscale dimension have been exploited with live-cell confocal microscopy imaging of human breast adenocarcinoma (MCF7) cells. The magnetic features of the Dy 2 Zn 6 complex confirm the single-molecule-magnet behavior with befitting frequency- and temperature-dependent out-of-phase signals along with an U eff value of ∼5 K and a relaxation time of 8.52 × 10–6 s. The Gd 2 Zn 6 complex, on the other hand, shows cryogenic magnetic refrigeration with an entropy change of 11.25 J kg–1 K–1 at a magnetic field of 7 T and at 2 K. Another important aspect of this work reflects the excellent agreement between the experimental results and theoretical calculations. The theoretical studies carried out using the broken-symmetry density functional theory, ORCA suite of programs, and MOLCAS calculations using the complete-active-space self-consistent-field method show an excellent synergism with the experimentally measured magnetic and spectroscopic data.