Field‐Induced SMM and Visible/NIR‐Luminescence Behaviour of Dinuclear Ln^III Complexes with 2‐Fluorobenzoate

Abstract

The reaction of Ln(NO 3 ) 2 ·6H 2 O salts (Ln = Nd, Eu, Gd, Tb, Dy, Er and Yb) with 2-fluorobenzoic acid (H-2-FBz) and 1,10-phenanthroline (phen) in ethanol/water mixture allows the isolation of dinuclear compounds of the formula [Ln 2 (2-FBz) 4 -(NO 3 ) 2 (phen) 2 ] {Ln = Nd (1), Eu (2), Gd (3), Tb (4), Dy (5), Er (6)} and [Yb 2 (2-FBz) 6 (phen) 2 ] (7). The solid-state photoluminescence [a] 1928 study of the complexes shows the 4f-4f lanthanide transitions in the visible range, in the cases of 2, 4 and 5, and in the NIR range for 1, 6 and 7. Magnetic studies reveal field-induced single-molecule-magnet (SMM) behaviour for compounds 1, 5, 6 and 7.

Molecular and Polymer Ln2M2 (Ln = Eu, Gd, Tb, Dy; M = Zn, Cd) Complexes with Pentafluorobenzoate Anions: The Role of Temperature and Stacking Effects in the Structure; Magnetic and Luminescent Properties

“…The use of co-ligands and/or d-metals in the design of lanthanide complexes leads to structural modification needed to improve their luminescent and/or magnetic properties due to additional antenna effect, control the geometry of the coordination polyhedra of lanthanide atoms, minimize interionic interactions, etc. [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. Fluorinated polycarboxylic acids are used for the synthesis of coordination polymers (CPs) as well as metal organic frameworks (MOFs).…”

High relaxation barrier in neodymium furoate-based field-induced SMMs

“…The first Nd-SIM reported in 2012, [NdTp 3 ], exhibited field-induced relaxation with a small thermal activation energy of U/k B = 4.1 K (100 Oe). 6 Eight field-induced Nd-SIMs 3,7-12 and three dimeric {Nd 2 } complexes [13][14][15] with higher barrier energies have been reported ever since, with POM derivative [Na 9 Nd (W 5 O 18 ) 2 ] 9…”

“…The Raman exponent for the two compounds was n ≈ 5 (1) and n ≈ 9 for (2), within the range of values usually reported for Nd ions. 3,10,13,20 Regarding the τ(H) dependence, some distinct differences are found for the two complexes: the τ QT term is much smaller for the diluted compound (2) than for (1), as a result of the reduced interactions. Yet, even for (2) it is necessary to apply a small field to suppress completely QT, which is still favored by the transversal component of the ground state.…”

Mononuclear Lanthanide Complexes with 18-Crown-6 Ether: Synthesis, Characterization, Magnetic Properties, and Theoretical Studies

“…It worth to mention that furthermore of the zero-field SMMs, many compounds exhibit slow relaxation of the magnetization under an external field. [13][14][15][16] Such magnetic field breaks the degeneracy of the up and down spin states by reducing the spin relaxation through quantum tunneling mechanism. Such systems are usually called field-induced single-molecule magnets, in contrast with those showing such behavior at zero field (zero-field single-molecule magnets).…”

“…Thus, the electron density is concentrated in such region, adopting a nondistorted disc shape resulting in a highly anisotropy system with a very large perpendicular magnetic moment. (11,7) and (13,7) active spaces were used for TbIII, DyIII, ErIII and YbIII systems respectively. For the TbIII system 7 septuplets and 140 quintuplets were used; for the DyIII system 21 sextets, 128 quadruplets and 98 doublets were used; for the ErIII system 35 quadruplets and 112 doublets were used; finally, for the YbIII system 7 doublets were used.…”