Single-molecule magnet involving strong exchange coupling in terbium(<scp>iii</scp>) complex with 2,2′-bipyridin-6-yl tert-butyl nitroxide

Kanetomo, Takuya; Yoshii, Shunsuke; Nojiri, Hiroyuki; Ishida, Takayuki

doi:10.1039/c5qi00098j

Cited by 28 publications

(9 citation statements)

References 54 publications

(51 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interactions of nitroxide radicals with metals have also been extensively studied, , in particular with rare-earth (RE) elements. − These reports have mainly focused on the magnetic properties of the nitroxide-RE complexes (Chart ).…”

Section: Introductionmentioning

confidence: 99%

Redox-Driven Chelation and Kinetic Separation of Select Rare Earths Using a Tripodal Nitroxide Proligand

et al. 2019

View full text Add to dashboard Cite

Separation of the rare-earth (RE) elements (Sc, Y, La–Lu) is challenging because of their similar chemical properties, but is necessary for their applications in renewable energy and electronic device technologies. The development of separation processes driven by kinetic factors represents a new area for this field. Herein, we disclose a novel method of separating select rare earths by reacting RE cyclopentadienides with the triradical species tris(2-tert-butylnitroxyl)benzylamine (1). The key proligand 1 was characterized using a variety of techniques including X-ray crystallography, magnetometry, and EPR spectroscopy. When applied to an equimolar mixture of La:Y cyclopentadienide complexes, different rates of chelation of these organometallic precursors by 1 were observed, affording a separation factor of 26 under the reported conditions.

show abstract

Section: Introductionmentioning

confidence: 99%

Redox-Driven Chelation and Kinetic Separation of Select Rare Earths Using a Tripodal Nitroxide Proligand

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The spin quantum numbers of Gd 3+ , Tb 3+ , and Dy 3+ are 7/2, 3, and 5/2, respectively.The Kramers theorem or spin‐parity effect tells us that the half‐integer‐spin systems must have a ground doublet state, leading to a double‐well potential structure favourable for SMMs. It may hold for the 1 and 3 case and not for the 2 case, even after addition or subtraction of two Ni 2+ spins.…”

Section: Resultsmentioning

confidence: 99%

Syntheses, Crystal Structure and Magnetic Properties of an Unprecedented One-Dimensional Coordination Polymer Derived from an {(NiL)₂Ln} Node and a Pyrazine Spacer (H₂L=N,N′-Bis(salicylidene)-1,3-propanediamine, Ln=Gd, Tb and Dy)

et al. 2016

Self Cite

View full text Add to dashboard Cite

In order to investigate the coordinative interaction of the [NiIIL] metalloligand with lanthanides (H2L =N,N′‐bis(salicylidene)‐1,3‐propanediamine or H2salpn) and the building block potential of the resultant unstable {(NiIIL)2LnIII} (LnIII=Lanthanides) complex with a short spacer pyrazine (pyz), three heterometallic coordination polymers of formulae [{(NiL)2Ln(NO3)3}pyz]n⋅1.5nH2O [Ln=Gd (1), Tb (2) and Dy (3)] have been synthesized. In these compounds the central LnIII ion is connected to two terminal [NiL] metalloligands through µ1,1‐diphenoxido bridges to form the trinuclear node with three nitrato coligands (LnO9 monocapped square‐antiprism). The coordinative preference of pyrazine ligand towards the NiII‐centre of the trinuclear units leads to the formation of these tailored 1D‐zigzag coordination polymers with transoidtrinuclear nodes. The magnetization at 1.8 K for 1 (10.4 μB at 7 T) indicates the presence of Gd−Ni ferromagnetic coupling through the phenoxido bridges. The exchange parameter was determined to be +0.179(4) K from the magnetic susceptibility measurement. Both in‐phase and out‐of‐phase ac magnetic measurements under an applied dc magnetic field reveal temperature dependence of the susceptibility at different frequencies below 5 K for compound 3, characteristic of single molecule magnets (SMMs) or polymeric aggregates of SMMs.

show abstract

“…The finding is again reasonable, according to the magneto-structural relationship (Figure 4). This supramolecular architecture was reproduced after replacing paramagnetic ligands with diamagnetic ones [114,[147][148][149]. This method simplifies the magnetic analysis.…”

Section: Low-spin Moleculesmentioning

confidence: 99%

“…Using a diamagnetic ligand HpzNTR (N-tert-butyl-α-3-pyrazolylnitrone), the trinuclear nickel(II,II,II) as well as iron(II,III,II) compounds were prepared, and their magnetic properties including triply pyrazolate-bridged superexchange interaction were investigated in detail [150]. This supramolecular architecture was reproduced after replacing paramagnetic ligands with diamagnetic ones [114,[147][148][149]. This method simplifies the magnetic analysis.…”

Section: Low-spin Moleculesmentioning

confidence: 99%

Molecular S = 2 High-Spin, S = 0 Low-Spin and S = 0 ⇄ 2 Spin-Transition/-Crossover Nickel(II)-Bis(nitroxide) Coordination Compounds

et al. 2021

Self Cite

View full text Add to dashboard Cite

Heterospin systems have a great advantage in frontier orbital engineering since they utilize a wide diversity of paramagnetic chromophores and almost infinite combinations and mutual geometries. Strong exchange couplings are expected in 3d–2p heterospin compounds, where the nitroxide (aminoxyl) oxygen atom has a direct coordination bond with a nickel(II) ion. Complex formation of nickel(II) salts and tert-butyl 2-pyridyl nitroxides afforded a discrete 2p–3d–2p triad. Ferromagnetic coupling is favored when the magnetic orbitals, nickel(II) dσ and radical π*, are arranged in a strictly orthogonal fashion, namely, a planar coordination structure is characterized. In contrast, a severe twist around the coordination bond gives an orbital overlap, resulting in antiferromagnetic coupling. Non-chelatable nitroxide ligands are available for highly twisted and practically diamagnetic complexes. Here, the Ni–O–N–Csp2 torsion (dihedral) angle is supposed to be a useful metric to describe the nickel ion dislocated out of the radical π* nodal plane. Spin-transition complexes exhibited a planar coordination structure in a high-temperature phase and a nonplanar structure in a low-temperature phase. The gradual spin transition is described as a spin equilibrium obeying the van’t Hoff law. Density functional theory calculation indicates that the energy level crossing of the high- and low-spin states. The optimized structures of diamagnetic and high-spin states well agreed with the experimental large and small torsions, respectively. The novel mechanism of the present spin transition lies in the ferro-/antiferromagnetic coupling switch. The entropy-driven mechanism is plausible after combining the results of the related copper(II)-nitroxide compounds. Attention must be paid to the coupling parameter J as a variable of temperature in the magnetic analysis of such spin-transition materials. For future work, the exchange coupling may be tuned by chemical modification and external stimulus, because it has been clarified that the parameter is sensitive to the coordination structure and actually varies from 2J/kB = +400 K to −1400 K.

show abstract

Single-molecule magnet involving strong exchange coupling in terbium(iii) complex with 2,2′-bipyridin-6-yl tert-butyl nitroxide

Cited by 28 publications

References 54 publications

Redox-Driven Chelation and Kinetic Separation of Select Rare Earths Using a Tripodal Nitroxide Proligand

Redox-Driven Chelation and Kinetic Separation of Select Rare Earths Using a Tripodal Nitroxide Proligand

Syntheses, Crystal Structure and Magnetic Properties of an Unprecedented One-Dimensional Coordination Polymer Derived from an {(NiL)₂Ln} Node and a Pyrazine Spacer (H₂L=N,N′-Bis(salicylidene)-1,3-propanediamine, Ln=Gd, Tb and Dy)

Molecular S = 2 High-Spin, S = 0 Low-Spin and S = 0 ⇄ 2 Spin-Transition/-Crossover Nickel(II)-Bis(nitroxide) Coordination Compounds

Contact Info

Product

Resources

About

Single-molecule magnet involving strong exchange coupling in terbium(iii) complex with 2,2′-bipyridin-6-yl tert-butyl nitroxide

Cited by 28 publications

References 54 publications

Redox-Driven Chelation and Kinetic Separation of Select Rare Earths Using a Tripodal Nitroxide Proligand

Redox-Driven Chelation and Kinetic Separation of Select Rare Earths Using a Tripodal Nitroxide Proligand

Syntheses, Crystal Structure and Magnetic Properties of an Unprecedented One-Dimensional Coordination Polymer Derived from an {(NiL)2Ln} Node and a Pyrazine Spacer (H2L=N,N′-Bis(salicylidene)-1,3-propanediamine, Ln=Gd, Tb and Dy)

Molecular S = 2 High-Spin, S = 0 Low-Spin and S = 0 ⇄ 2 Spin-Transition/-Crossover Nickel(II)-Bis(nitroxide) Coordination Compounds

Contact Info

Product

Resources

About

Syntheses, Crystal Structure and Magnetic Properties of an Unprecedented One-Dimensional Coordination Polymer Derived from an {(NiL)₂Ln} Node and a Pyrazine Spacer (H₂L=N,N′-Bis(salicylidene)-1,3-propanediamine, Ln=Gd, Tb and Dy)