Slow magnetic relaxation in two new 1D/0D Dy(III) complexes with a sterically hindered carboxylate ligand

Two 3d–4f double helical chains including [Dy2M2]n (M = NiII and CoII) cores exhibiting slow magnetic relaxation

Two new heterometallic complexes with one-dimensional ladder-like double-helical chain structures were prepared. They both exhibit interesting magnetic properties.

Magnetic relaxation versus 3D long-range ordering in {Dy₂Ba(α-fur)₈}n furoate polymers

A novel Dy-complex formulated as {[Dy2Ba(α-C4H3OCOO)8·(H2O)4]·2H2O}n, {Dy2Ba(α-fur)8}n, has been synthesized, structurally characterized, and magnetically and thermally investigated as a function of field and temperature, down to 85 mK. The α-furoate ligands consolidate 1D zig-zag chains formed by Dy2 dimers separated by Ba ions. Ab initio calculations were used to determine the easy anisotropy axis direction, the gyromagnetic tensor components and the energy levels of each Dy. The heat capacity and susceptibility measurements allowed us to conclude that intradimer and interdimer interactions are ferromagnetic and of the same order, J'/k(B) ≈ J''/k(B) = +0.55 K. In the absence of an applied magnetic field, the dynamic relaxation of the magnetization occurs through the fast (τ(T) ~ 10(-5) s) spin-reversal of each of the individual Dys through a quantum tunneling (QT) process. A long-range 3D ordered state is achieved at T(N) = 0.25 K, in which the ferromagnetically coupled zig-zag chains (J'/k(B) ≈ J''/k(B) = +0.528(1) K) running along the c-axis are antiferromagnetically coupled to the adjacent chains (J'''/k(B) = -0.021(1) K). Critical slowing down of the QT time constant is observed when the temperature approaches T(N). Under the application of a magnetic field, the QT relaxation is replaced by an Orbach process (with energy barrier U/k(B) = 68 K and τ0 ~ 10(-9) s at H = 2 kOe) and a very slow (τ(s) ∼ 0.2 s) relaxation process. We propose and demonstrate the proof of concept of a spintronic device, in which two different relaxation rates can be selected, and on/off switched by magnetic field biasing. The dynamical behavior of this compound is compared with another furoate to discuss the effect of competitive interactions.

Slow magnetic relaxation in a novel carboxylate/oxalate/hydroxyl bridged dysprosium layer

2D dysprosium complex exhibiting slow magnetic relaxation originating from the strong Ising anisotropy of single Dy³⁺ ions has been reported.

A new 2D dysprosium layer compound has been successfully synthesized from reaction with 2-(3-pyridyl) pyrimidine-4-carboxylic acid (H3-py-4-pmc), in which the Dy³⁺ ions reside in square antiprismatic coordination environments and are connected by carboxylate/oxalate/hydroxyl bridges. Magnetic studies reveal ferromagnetic interactions between Dy³⁺ ions, slow magnetic relaxation with an effective energy barrier U_eff of 186 K under zero dc field and pronounced hysteresis loops at low temperatures. Further dilution magnetic study suggests that the slow magnetic relaxation originates from the single-ion magnetic behavior of Dy³⁺ ion and that magnetic coupling suppresses the quantum tunneling of magnetization at low temperature. In addition, theoretical calculation indicates strong Ising anisotropy of the Dy³⁺ ion that is due to the strong interaction between Dy³⁺ ions and hydroxyl groups.

Homochiral luminescent lanthanide dinuclear complexes derived from a chiral carboxylate

A family of chiral Ln₂ clusters based on a chiral monocarboxylate ligand has been successfully constructed via a diffusion method, and Eu, Tb and Dy analogues display good luminescent properties.

Pentanuclear [2.2] spirocyclic lanthanide(iii) complexes: slow magnetic relaxation of the DyIII analogue

A series of [2.2] spirocyclic complexes [Ln₅(LH)₄(η¹-Piv)(η²-Piv)₃(μ₂–η² η¹Piv)₂(H₂O)]·Cl (Ln = Dy^III, Tb^III and Ho^III) were synthesized. Magnetic analysis reveals that the Dy^III analogue showed slow relaxation of magnetization.

Two novel 3d–4f heterometallic coordination polymers with infinite [Ln4(OH)4]n8n+ chains involving in situ decarboxylation

Two novel heterometallic coordination polymers with infinite Ln₄(OH)₄]_n⁸ⁿ⁺ chains [Ln₄Co(QDA)₂(QA)₆(OH)₄(H₂O)₄] (Ln = Tb1, Dy2; H₂QDA = 2,3-quinolinedicarboxylic acid, HQA = 3-quinolinecarboxylic acid) have been achieved.

Multiple thermal magnetic relaxation in a two-dimensional ferromagnetic dysprosium(iii) metal–organic framework

Intramolecular ferromagnetic interaction exists in a dysprosium(iii) MOF with a highly ordered 2D (4, 4) grid network, showing two-step thermal magnetic relaxation.

Temperature-controlled polymorphism of chiral CuII–LnIII dinuclear complexes exhibiting slow magnetic relaxation

A family of chiral Cu–Ln dinuclear complexes with two different space groups has been constructed. The temperature-controlled reversible conversion from one chiral single-crystal to another chiral single-crystal with slow magnetic relaxation has been achieved.

A simple route to a 1D ferromagnetic Dy-containing compound showing magnetic relaxation behaviour

The relatively rare well-isolated 1D ferromagnetic chain of the Dy analogue displays magnetic relaxation behaviour.

Tuning the magnetic behaviors in [FeIII12LnIII4] clusters with aromatic carboxylate ligands

Six new Fe–Ln clusters composed of a Fe₁₂Ln₄ core derived from two monocarboxylate ligands have been successfully obtained with a step-by-step strategy. Magnetic analyses suggest that 1–6 show different magnetic properties, and 2 and 6 display SMM-like behaviors.

[Dy(acac)3(dppn)]·C2H5OH: construction of a single-ion magnet based on the square-antiprism dysprosium(iii) ion

The present work reports a new mononuclear Dy(iii) complex [Dy(acac)₃(dppn)]·C₂H₅OH (1) (acac = acetylacetone, dppn = benzo[i]dipyrido-[3, 2-a:2′,3′-c]phenazine).

Slow magnetic relaxation in tris(diphosphanylamido) and tetra(phosphanoamido) dysprosium complexes

Two homoleptic phosphanylamido dysprosium complexes [Li(THF)4][(Ph2PNPh)4Dy] and [Dy{N(PPh2)2}3] have been synthesized. Both have a highly symmetric arrangement of the ligand which is only slightly broken in the solid state by steric and packing effects as a result of the weak coordination of phosphorus atoms to the metal centre. Magnetic properties of these two compounds are similar with both showing slow magnetic relaxation.

Syntheses, structures, and magnetic properties of seven-coordinate lanthanide porphyrinate or phthalocyaninate complexes with Kläui's tripodal ligand

A series of seven-coordinate mononuclear lanthanide(III) complexes of the general formula [(TPP)Ln(L(OEt))]·0.25H2O and [(Pc)Ln(L(OEt))] (Ln(3+) = Dy(3+), Tb(3+), Ho(3+), and Gd(3+); TPP = 5,10,15,20-tetraphenylporphyrinate; Pc = phthalocyaninate; L(OEt)(-) = [(η(5)-C5H5)Co(P(=O)(OEt)2)3](-)) are synthesized on the basis of the tripodal ligand L(OEt)(-) and either porphyrin or phthalocyanine ligands. All of the complexes are characterized by X-ray crystallography and by static and dynamic magnetic measurements. The Dy and Tb complexes show the field-induced slow relaxation of magnetization, and they are interesting seven-coordinate single-lanthanide-based SMMs. The magnetic relaxation properties of these double-decker sandwich complexes are influenced by the local molecular symmetry and are sensitive to subtle distortions of the coordination geometry of the paramagnetic lanthanide ions, such as metal-to-plane distances, plane center distances, and bending angles.