Homodinuclear {Ln^III₂} (Ln^III = Gd^III, Tb^III, Ho^III, and Dy^III) Complexes: Field‐Induced SMM Behavior of the Dy^III and Tb^III Analogues

Abstract

A family of four dinuclear complexes, [NHEt3]2[Ln2(µ‐NO3)2(NO3)2(HL)2] [Ln = GdIII (1), TbIII (2), HoIII (3), DyIII (4)], were synthesized by the reaction of an enolizable multidentate Schiff base ligand H3L (H3L = N′‐(2‐hydroxy‐3‐methoxy‐5‐nitrobenzylidene)‐2‐(hydroxyimino)propanehydrazide) with hydrated lanthanide nitrates in the presence of NEt3. The molecular structure of complexes 1–4 was confirmed by single‐crystal XRD analysis. All of the centrosymmetric complexes are dianionic, isostructural and each of the LnIII centers is nine‐coordinate and adopts a muffin like coordination geometry as indicated by SHAPE analysis. The dynamic magnetization studies revealed that the compounds 2 and 4 are field‐induced single‐molecule magnets with effective energy barriers,Ueff = 34(2) K (for 2) and 80(3) K (for 4) and pre‐exponential factors, τo = 1.1 × 10–8 s (for 2) and 1.15 × 10–7 s (for 4).

Luminescent and magnetic bifunctional coordination complex based on a chiral tartaric acid derivative and europium

“…Adjacent Eu 3+ ions are bonded to three HDTTA À ligands in a three-ply mode more tightly than the Ln-CPs based on another tartaric acid derivative, dibenzoyl tartaric acid (H 2 DBTA), which features a ladder or linear chain in a two-ply mode (Li et al, 2017b;Sun et al, 2016). The Eu-O bond lengths and O-Eu-O bond angles are in the ranges 2.324 (5)-2.585 (6) Å and 63.50 (18)-140.64 (19) , respectively, and are comparable to those reported in the literature for similar compounds (Gá mez-Heredia et al, 2019; He et al, 2018;Kalita et al, 2019). Such a structure is similar to that of a reported 1D linear neodymium coordination polymer in which the l-H 2 DTTA ligand was employed with different deprotonation (Niu et al, 2016a).…”

“…Over the past few years, lanthanide-based coordination polymers (Ln-CPs) with tailorable structures have attracted a great deal of attention, not only because of their aesthetically fascinating structures, but also due to their potential applications as functional materials, such as in gas adsorption, catalysis, molecule and ion sensors, magnetism and fluorescence (Biswas et al, 2014;Giansiracusa et al, 2018;Wang et al, 2016;Wei et al, 2014;Wu et al, 2018;Zhang et al, 2018). As is well known, most lanthanide ions possess strong unquenched orbital angular momentum and large spin-orbit coupling of the 4f electrons, so that they can contribute to the acquisition of single-ion magnets (SIMs) (Cepeda et al, 2012;Farger et al, 2018;Zhao et al, 2015) and single-molecule magnets (SMMs) (Bartolomé et al, 2018;Jassal et al, 2018;Kalita et al, 2019). Apart from their excellent magnetic properties, most Ln-CPs also display characteristic sharp and narrow luminescence emissions originating from f-f transitions of the Ln 3+ ions, featuring excellent colour purity, long fluorescence lifetimes and high quantum yields (Roy et al, 2014;Xu et al, 2017;Zhang et al, 2017).…”

Three chiral one-dimensional lanthanide–ditoluoyl-tartrate bifunctional polymers exhibiting luminescence and magnetic behaviors

“…25,45 The Tb-O bond lengths and O-Tb-O bond angles fall in the range of 2.302(6)-2.554(8)Å and 63.7(2)-140.3(3) (Table S1 †), respectively, comparable to those reported in the literatures. [46][47][48] The previously reported Nd 3+ coordination compound with l-H 2 DTTA Notable are the patterns of snowakes viewed from the crystallographic c-axis of complex 1, and the molecules are fully eclipsed (Fig. 4a).…”

Magnetic Behavior of Luminescent Dinuclear Dysprosium and Terbium Complexes Derived from Phenoxyacetic Acid and 2,2′-Bipyridine

“…The m value was fixed to be 3 for the best fitting. Generally, the expected value of m is 9 for a Kramers ion like dysprosium, but values between 2 and 7 are acceptable for acoustic and optical phonon Raman [53,54]. The extracted anisotropic energy barrier is ΔE = 16.261 cm −1 with the relaxation time (τ0) = 2.425 × 10 −8 s (Figure 4 and Table S5).…”