Linear {NiII–LnIII–NiII} Complexes Containing Twisted Planar Ni(μ‐phenolate)2Ln Fragments: Synthesis, Structure, and Magnetothermal Properties

Das, Sourav; Dey, Atanu; Kundu, Subrata; Biswas, Sourav; Mota, Antonio J.; Colacio, Enrique; Chandrasekhar, Vadapalli

doi:10.1002/asia.201402062

Cited by 22 publications

(25 citation statements)

References 83 publications

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“…It is well known that multi‐compartmental Schiff base ligands are an excellent host to assemble 3d‐4f hybrid molecules , . The multisite coordinating Schiff base ligand LH 3 was synthesized by condensation reaction in methanol of 2‐(hydroxymethyl)‐6‐carbaldehyde‐4‐methylphenol, with 2‐aminophenol.…”

Section: Resultsmentioning

confidence: 99%

Pentanuclear Spirocyclic Ni₄Ln Derivatives: Field Induced Slow Magnetic Relaxation in the Dysprosium and Erbium Analogues

et al. 2020

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Five pentanuclear heterometallic isostructural complexes, [Ni4Ln(L)2(LH)2(CH3CN)3Cl]·xH2O·yCH3OH {Ln = YIII (1), GdIII (2), TbIII (3), DyIII (4) and ErIII (5)} [for 1 and 2, x = 2, y = 1; for 3, x = 6, y = 2; for 4, x = 5, y = 1; for 5, x = 2, y = 2] were prepared by the reaction of (E)‐2‐(hydroxymethyl)‐6‐{[(2‐hydroxyphenyl)imino]methyl}‐4‐methylphenol (LH3) with LnCl3·6H2O and Ni(OAc)2·4H2O in the presence of tetrabutylammonium hydroxide (TBA‐OH) base. The structural characterization reveals that compounds 1–5 contain a spirocyclic pentanuclear core [Ni4Ln(µ3‐O)4(µ2‐O)4]3+ where two triangular motifs [Ni2Ln(µ3‐O)2(µ2‐O)2]3+ are fused together through a common vertex of the LnIII ion. The central LnIII ion forms an eight‐coordinated distorted triangular dodecahedron geometry, while the nickel(II) ions form a distorted octahedron geometry. Comprehensive dc magnetic studies reveal that antiferromagnetic exchange interaction exists between the NiII centres. The ac susceptibility measurement revels that dysprosium and erbium analogue shows field induced slow magnetic relaxation with an anisotropic barrier (Ueff) of 25.12 cm–1 and 22.13 cm–1 respectively.

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Section: Resultsmentioning

confidence: 99%

Pentanuclear Spirocyclic Ni₄Ln Derivatives: Field Induced Slow Magnetic Relaxation in the Dysprosium and Erbium Analogues

et al. 2020

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“…Recently, we have been experimenting with various types of ligands for the purpose of knowing their discriminatory capability in terms of directing homonuclear lanthanide assemblies versus heteronuclear 3d/4f complexes 11. Thus, the ligands, 2‐(hydroxymethyl)‐6‐carbaldehyde‐4‐methylphenol ( C2 ) and the Schiff base derivative (2‐(2‐hydroxy‐3‐(hydroxymethyl)‐5‐methylbenzylideneamino)‐2‐methylpropane1,3‐diol) afforded pentanuclear M 4 Ln11a, b and M 2 Ln11c, d, e derivatives respectively (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

“… a) Pentanuclear M 4 Ln11a, b and b) trinuclear M 2 Ln11c, d, e derived from C2 and its Schiff base derivative, respectively. …”

Section: Resultsmentioning

confidence: 99%

Decanuclear Ln₁₀ Wheels and Vertex‐Shared Spirocyclic Ln₅ Cores: Synthesis, Structure, SMM Behavior, and MCE Properties

Das

Dey

Kundu

et al. 2015

Chemistry A European J

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The reaction of a Schiff base ligand (LH3) with lanthanide salts, pivalic acid and triethylamine in 1:1:1:3 and 4:5:8:20 stoichiometric ratios results in the formation of decanuclear Ln10 (Ln = Dy (1), Tb (2), and Gd (3)) and pentanuclear Ln5 complexes (Ln = Gd (4), Tb (5), and Dy (6)), respectively. The formation of Ln10 and Ln5 complexes are fully governed by the stoichiometry of the reagents used. Detailed magnetic studies on these complexes (1-6) have been carried out. Complex 1 shows a SMM behavior with an effective energy barrier for the reversal of the magnetization (Ueff) = 16.12(8) K and relaxation time (τo) = 3.3×10(-5) s under 4000 Oe direct current (dc) field. Complex 6 shows the frequency dependent maxima in the out-of-phase signal under zero dc field, without achieving maxima above 2 K. Complexes 3 and 4 show a large magnetocaloric effect with the following characteristic values: -ΔSm = 26.6 J kg(-1) K(-1) at T = 2.2 K for 3 and -ΔSm = 27.1 J kg(-1) K(-1) at T = 2.4 K for 4, both for an applied field change of 7 T.

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“…Using{2‐[2‐hydroxy‐3‐(hydroxymethyl)‐5‐methylbenzylideneamino]‐2‐methylpropane‐1,3‐diol} (L 16 H 4 ), the trinuclear complexes [Ni II 2 Ln III (L 16 H 3 ) 4 ](NO 3 ) 3 [Ln III =Gd III ( 103 ), Tb III ( 104 ), Dy III ( 105 ) and Ho III ( 106 )] were prepared (Figure ) . Magnetic measurements revealed a predominant ferromagnetic interaction between the Ni II and Ln III centers ( J NiGd =+0.75 cm −1 ).…”

Section: Niii‐lniii Complexesmentioning

confidence: 99%

Heterometallic 3d–4f Complexes as Single‐Molecule Magnets

Dey

Acharya

Chandrasekhar

2019

Chemistry An Asian Journal

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Heterometallic 3d-4fc omplexes are being investigated, for some time, as being useful in molecular magnetism, particularly as single-molecule magnets (SMMs). This interest is primarily because of the possibility of an increased ligand-mediated super-exchange phenomenon between the 3d and 4f metal ions. Such an interaction, apart from bestowing af avorable ground-state spin to the complex, also assists in reducing quantum tunneling of magnetization that is widely prevalenti nS MMs making them to lose magnetization. However,a ssembling both 3d as well as 4f ions using same ligand system is challenging and involves the design of multi-site coordination ligandsw ith specific coordination compartments for the 3d and the 4f metal ions while at the same time allowing these disparate metal ions to be linked to each other through ab ridging ligatinga tom. This review presents as ummary of the 3d-4f complexes primarily derived from the author's work while alluding to importante xamplesf rom the literature. We also provide an outlookf or the future design of such complexes.[a] Dr.A .Dey, Prof. V. Chandrasekhar 4434Minireview dro-imidazol-2-ylidenea nd DmpN 3 = 2,6-dimesitylphenyl azide] which exhibit slow magnetic relaxation with U eff values of 450 and 413 cm À1 respectively. [13][14][15] Similarly,t here have been reports on mononuclear lanthanide complexes [12a, 16] ever since the seminalp aper on the first lanthanide based SMM in 2003, (Bu 4 N)[Ln III (Pc) 2 ] [17] [Ln III = Tb III (7)a nd Dy III (8); Pc = phthalocyaninato].R ecently,t he complexes [(Cp ttt ) 2 Dy III ][B(C 6 F 5 ) 4 ] [18] (9) (Cp ttt [19] (10)h ave been reported with blockingt emperatures of 60 and 80 Kr espectively.C omplex 10 holds the record for the highest reported energy barrier U eff = 1541 cm À1 for the reversal of magnetization.One of the problemsa ssociated with SMMs is that the magnetization can be lost by av ariety of ways including quantum tunneling mechanism (QTM) which shortcuts the energy barriers of relaxation. [6b] This is an important impediment and progress in this field is dependent on minimizing or eliminating QTM. There are many strategies to do this including assembling mononuclear complexes possessing point-group symmetries such as C 1v , D 1h , S 8 (I 4 ), D 4d , D 5d and D 5h[12a] or by increasing the ferromagnetic coupling between the adjacent lanthanide centers,a ne xample of this being the dinuclearc omplex [K(18crown-6)]{[((Me 3 Si) 2 n) 2 (THF)Dy III ] 2 (m-h 2 :h 2 -N 2 )} (11)w here the radicall igand, N 2 3À , [20] facilitates af erromagnetic exchange between the two lanthanide centers. [21] Another strategy is to involve heterometallic transition metal/lanthanide complexes where as uper-exchange ferromagnetic interaction between the lanthanide and transition metal ion can mitigate QTM. [22] Accordingly,t he first 3d-4fb ased SMM, a[ Cu II 2 Tb III 2 ]( 12) complex, was reported by Osa and co-workers in 2004. [23] Murray and co-workers have successfully utilized this strategy for av ariety of complexes with {Cr II...

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Linear {Ni^II–Ln^III–Ni^II} Complexes Containing Twisted Planar Ni(μ‐phenolate)₂Ln Fragments: Synthesis, Structure, and Magnetothermal Properties

Cited by 22 publications

References 83 publications

Pentanuclear Spirocyclic Ni₄Ln Derivatives: Field Induced Slow Magnetic Relaxation in the Dysprosium and Erbium Analogues

Pentanuclear Spirocyclic Ni₄Ln Derivatives: Field Induced Slow Magnetic Relaxation in the Dysprosium and Erbium Analogues

Decanuclear Ln₁₀ Wheels and Vertex‐Shared Spirocyclic Ln₅ Cores: Synthesis, Structure, SMM Behavior, and MCE Properties

Heterometallic 3d–4f Complexes as Single‐Molecule Magnets

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Linear {NiII–LnIII–NiII} Complexes Containing Twisted Planar Ni(μ‐phenolate)2Ln Fragments: Synthesis, Structure, and Magnetothermal Properties

Cited by 22 publications

References 83 publications

Pentanuclear Spirocyclic Ni4Ln Derivatives: Field Induced Slow Magnetic Relaxation in the Dysprosium and Erbium Analogues

Pentanuclear Spirocyclic Ni4Ln Derivatives: Field Induced Slow Magnetic Relaxation in the Dysprosium and Erbium Analogues

Decanuclear Ln10 Wheels and Vertex‐Shared Spirocyclic Ln5 Cores: Synthesis, Structure, SMM Behavior, and MCE Properties

Heterometallic 3d–4f Complexes as Single‐Molecule Magnets

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Linear {Ni^II–Ln^III–Ni^II} Complexes Containing Twisted Planar Ni(μ‐phenolate)₂Ln Fragments: Synthesis, Structure, and Magnetothermal Properties

Pentanuclear Spirocyclic Ni₄Ln Derivatives: Field Induced Slow Magnetic Relaxation in the Dysprosium and Erbium Analogues

Pentanuclear Spirocyclic Ni₄Ln Derivatives: Field Induced Slow Magnetic Relaxation in the Dysprosium and Erbium Analogues

Decanuclear Ln₁₀ Wheels and Vertex‐Shared Spirocyclic Ln₅ Cores: Synthesis, Structure, SMM Behavior, and MCE Properties