Butterfly‐Shaped Pentanuclear Dysprosium Single‐Molecule Magnets

Two new “butterfly‐shaped” pentanuclear dysprosium(III) clusters, [Dy₅(μ₃‐OH)₃(opch)₆(H₂O)₃] ? 3 MeOH ? 9 H₂O ( 1 ) and [Dy₅(μ₃‐OH)₃(Hopch)₂(opch)₄(MeOH)(H₂O)₂] ? (ClO₄)₂ ? 6 MeOH ? 4 H₂O ( 2 ), which were based on the heterodonor‐chelating ligand o‐vanillin pyrazine acylhydrazone (H₂opch), have been successfully synthesized by applying different reaction conditions. Single‐crystal X‐ray diffraction analysis revealed that the butterfly‐shaped cores in both compounds were comparable. However, their magnetic properties were drastically different. Indeed, compound 1 showed dual slow‐relaxation processes with a transition between them that corresponded to energy gaps (Δ) of 8.1 and 37.9 K and pre‐exponential factors (τ₀) of 1.7×10^?5 and 9.7×10^?8 s for the low‐ and high‐temperature domains, respectively, whilst only a single relaxation process was noted for compound 2 (Δ=197 K, τ₀=3.2×10^?9 s). These significant disparities are most likely due to the versatile coordination of the H₂opch ligands with particular keto–enol tautomerism, which alters the strength of the local crystal field and, hence, the nature or direction of the easy axes of anisotropic dysprosium ions.     

Copolymerization of carbon dioxide with cyclohexene oxide catalyzed by bimetallic dysprosium complexes containing hydrazine‐functionalized Schiff‐base derivatives

A series of dinuclear Dy^III acetate complexes containing three different hydrazine‐functionalized Schiff‐base ligands ( hmb , hmi, and hb ) have been synthesized by one‐pot reaction with Dy(OAc)₃·4H₂O as the metal precursor. [Dy₂( hmb )₂(OAc)₄]·MeCN ( 1 ·MeCN) and [Dy₂( hmi )₂(OAc)₂(MeOH)₂]·H₂O ( 2 ·H₂O) with keto and enol forms of the corresponding ligands, respectively, were shown the similar core structures but different ratio of Dy^III to OAc^–. Moreover, the different coordination environments of complex [Dy₂( hb )₂(μ‐OAc)₂(OAc)₂(H₂O)₂]·DMF·H₂O ( 3 ·DMF·H₂O) also offered an opportunity to understand the relationship between structural model and catalytic properties. Bimetallic dysprosium complexes 1 – 3 were demonstrated to be active catalysts for copolymerization of carbon dioxide (CO₂) and cyclohexene oxide (CHO) without cocatalysts. To the best of our knowledge, well‐defined catalyst 2 appears to be the first example of an air‐stable bimetallic dysprosium complex that is effective for CO₂/CHO copolymerization and the formation of the perfectly alternating poly(cyclohexenecarbonate) with a high molecular weight. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 321–328     

Four Dysprosium(III) Compounds Based On 1H‐Benzimidazole‐5,6‐dicarboxylic Acid via Hydrothermal Synthesis

Four compounds [Dy(H₂bidc)(Hbidc)(H₂O)₈] · 8H₂O ( 1 ), {[Dy(Hbidc)(H₂O)₂(Htzac)] · 3H₂O}_n ( 2 ), [Dy(C₂O₄)_0.5(Hbidc)(H₂O)₃]_n ( 3 ), {[Dy₂(Hbidc)₂(H₂O)(SO₄)] · H₂O}_n ( 4 ) (H₃bidc = 1H‐benzimidazole‐5,6‐dicarboxylic acid, H₂tzac = 1H‐3‐amino‐5‐carboxy‐1,2,4‐triazole) were synthesized with hydrothermal synthesis and structurally characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. X‐ray analysis revealed that the four coordination compounds have different structures: Compound 1 is a three dimensional supermolecular structure joined by hydrogen bonding interactions based upon dinuclear units. Compound 2 is a three dimensional supermolecular structure combined by hydrogen‐bonding interactions based upon one dimensional coordination chain including a T4(1)‐type water cluster chain. The structure of compound 3 is built of two dimensional (3,6)‐connected kgd‐type (4³)₂(4⁶.6⁶.8³) layers with a right‐handed and a left‐handed helical chain, which are further extended into three dimensional supramolecular architecture by hydrogen bonding interactions. Compound 4 displays a three dimensional framework containing a dinuclear dysprosium building unit with a (3,8)‐connected (4.5²)₂(4².5¹⁰.6¹².7.8³) topological framework. In addition, the photoluminescent property of compound 3 was investigated.     

一维和二维镝(Ⅲ)配合物的慢磁弛豫

分别用稀土醋酸盐和稀土高氯酸盐与希弗碱配体和巯基烟酸配体反应得到了两例镝配合物[Dy₂(OAc)₆H₂O]_n(1)和{[DyL(H₂O)₄]ClO₄·H₂O}_n(2)(L=2,2'-二硫代-二(3-吡啶甲酸)),并通过单晶X-射线衍射、元素分析、红外光谱和磁性测试对其进行了表征。结构研究和磁性测试表明:化合物1是羧基桥连的一维链结构,该化合物表现出慢磁弛豫性质,有效能垒为2 K;化合物2是通过原位生成的二硫键桥连的二维网状结构,表现出明显的铁磁相互作用和慢磁弛豫行为。     

Tuning the Magnetic Interactions and Relaxation Dynamics of Dy2 Single‐Molecule Magnets

Efficient modulation of single‐molecule magnet (SMM) behavior was realized by deliberate structural modification of the Dy₂ cores of [Dy₂( a ′ povh )₂(OAc)₂(DMF)₂] ( 1 ) and [Zn₂Dy₂( a′povh )₂(OAc)₆] ? 4 H₂O ( 2 ; H₂ a ′ povh =N′‐[amino(pyrimidin‐2‐yl)methylene]‐o‐vanilloyl hydrazine). Compound 1 having fourfold linkage between the two dysprosium ions shows high‐performance SMM behavior with a thermal energy barrier of 322.1 K, whereas only slow relaxation is observed for compound 2 with only twofold connection between the dysprosium ions. This remarkable discrepancy is mainly because of strong axiality in 1 due to one pronounced covalent bond, as revealed by experimental and theoretical investigations. The significant antiferromagnetic interaction derived from bis(μ₂‐O) and two acetate bridging groups was found to be crucial in leading to a nonmagnetic ground state in 1 , by suppressing zero‐field quantum tunneling of magnetization.     

Synthesis and Characterization of Two Discrete Ln10 Nanoscopic Ladder‐Type Cages: Magnetic Studies Reveal a Significant Cryogenic Magnetocaloric Effect and Slow Magnetic Relaxation

Two unique lanthanide‐based cages [Ln₁₀( L )₅(μ₂‐OH)₆(H₂O)₂₂](Cl)₄?7 H₂O ([Gd₁₀] and [Dy₁₀]) have been synthesized by using a hydrazone‐based ligand H₄ L (H₄ L =2,6‐bis[(3‐methoxysalicylidene)hydrazinecarbonyl]pyridine) and LnCl₃?x H₂O. Structural characterization of [Gd₁₀] reveals an aesthetically pleasing self‐assembly of five L ^4? and ten Gd³⁺ ions forming a 2×[1×5] rectangular array. The ladder‐shaped cage consists of three “rungs” and two “rails” that are occupied by five ligands. Six out of ten gadolinium centers act as rung locks. Further analysis revealed that three chloride ions are encapsulated inside each discrete [Gd₁₀] molecule through hydrogen bonding and other noncovalent interactions. Both the complexes ([Gd₁₀] and [Dy₁₀]) were characterized by powder X‐ray diffraction and thermogravimetric analysis, which shows that they are isostructural in nature. Magnetic investigations reveal that [Gd₁₀] is a good candidate for magnetic refrigeration with a significant entropy change (?ΔS_m) of 37.4 J kg^?1 K^?1 for an applied field of 7 T and at 3 K. Whereas [Dy₁₀] shows single‐molecule‐magnet‐like behavior.     

A Dy2 Dimer Embedded in One Salen‐type Ligand with Different Local Symmetries Behaves as Zero‐field Single‐Molecule Magnet

A salen‐type Dy₂ complex [Dy₂(L)(MeOH)₂(CH₃COO)₄] · 2(MeOH) was isolated and magnetically characterized, in which one hexadentate ligand H₂L [H₂L = N,N‐bis(2‐oxy‐3‐methoxybenzylidene)‐1,2‐phenylenediamine] chelated two Dy^III ions, one is located on the apical position of the inner N₂O₂ site, leaving the outer O₂O₂ cavity for another Dy^III ion. There are two distinct local coordination environments presented as square antiprism (D_4d) for Dy1 and biaugmented trigonal prism (C_2v) for Dy2. Magnetic measurements reveal that the ferromagnetic interaction between two Dy^III ions occurred within low temperature range and accompanied with significant slow magnetic relaxation behavior with energy barriers to the reversal of magnetization U_eff/K_B = 40 K under zero dc field.     

White Light Emissive DyIII Single‐Molecule Magnets Sensitized by Diamagnetic [CoIII(CN)6]3− Linkers

The self‐assembly of Dy^III–3‐hydroxypyridine (3‐OHpy) complexes with hexacyanidocobaltate(III) anions in water produces cyanido‐bridged {[Dy^III(3‐OHpy)₂(H₂O)₄] [Co^III(CN)₆]}?H₂O ( 1 ) chains. They reveal a single‐molecule magnet (SMM) behavior with a large zero direct current (dc) field energy barrier, ΔE=266(12) cm^?1 (≈385 K), originating from the single‐ion property of eight‐coordinated Dy^III of an elongated dodecahedral geometry, which are embedded with diamagnetic [Co^III(CN)₆]^3? ions into zig‐zag coordination chains. The SMM character is enhanced by the external dc magnetic field, which results in the ΔE of 320(23) cm^?1 (≈460 K) at H_dc=1 kOe, and the opening of a butterfly hysteresis loop below 6 K. Complex 1 exhibits white Dy^III‐based emission realized by energy transfer from Co^III and 3‐OHpy to Dy^III. Low temperature emission spectra were correlated with SMM property giving the estimation of the zero field ΔE. 1 is a unique example of bifunctional magneto‐luminescent material combining white emission and slow magnetic relaxation with a large energy barrier, both controlled by rich structural and electronic interplay between Dy^III, 3‐OHpy, and [Co^III(CN)₆]^3?.     

Coordination and hydrogen‐bonding assemblies in hybrid reaction products between 5,10,15,20‐tetra‐4‐pyridylporphyrin and dysprosium trinitrate hexahydrate

Reactions of the title free‐base porphyrin compound (TPyP) with dysprosium trinitrate hexahydrate in different crystallization environments yielded two solid products, viz. [μ‐5,15‐bis(pyridin‐1‐ium‐4‐yl)‐10,20‐di‐4‐pyridylporphyrin]bis[aquatetranitratodysprosium(III)] benzene solvate, [Dy₂(NO₃)₈(C₄₀H₂₈N₈)(H₂O)₂]·C₆H₆, (I), and 5,10,15,20‐tetrakis(pyridin‐1‐ium‐4‐yl)porphyrin pentaaquadinitratodysprosate(III) pentanitrate diethanol solvate dihydrate, (C₄₀H₃₀N₈)[Dy(NO₃)₂(H₂O)₅](NO₃)₅·2C₂H₆O·2H₂O, (II). Compound (I) represents a 2:1 metal–porphyrin coordinated complex, which lies across a centre of inversion. Two trans‐related pyridyl groups are involved in Dy coordination. The two other pyridyl substituents are protonated and involved in intermolecular hydrogen bonding along with the metal‐coordinated water and nitrate ligands. Compound (II) represents an extended hydrogen‐bonded assembly between the tetrakis(pyridin‐1‐ium‐4‐yl)porphyrin tetracation, the [Dy(NO₃)₂(H₂O)₅]⁺ cation and the free nitrate ions, as well as the ethanol and water solvent molecules. This report provides the first structural characterization of the exocyclic dysprosium complex with tetrapyridylporphyrin. It also demonstrates that charge balance can be readily achieved by protonation of the peripheral pyridyl functions, which then enhances their capacity in hydrogen bonding as H‐atom donors rather than H‐atom acceptors.     

Effects of substituents on bridging ligands on the single‐molecule magnet properties of Zn2Dy2 cluster complexes

Two new Zn₂Dy₂ complexes were constructed from Zn (II) salen‐type Schiff base complex fragment and 2,6‐pyridinedimethanol (H₂pdm) or its Br‐substituted analogue (4‐bromopyridine‐2,6‐diyl)dimethanol (H₂Brpdm); their molecular formulas are [Zn₂Dy₂(L)₂(pdm)₂(MeOH)₂](ClO₄)₂ [ 1 , H₂L = N, N′‐ bis(3‐methoxysalicylidene)‐1,3‐diaminopropane] and [Zn₂Dy₂(L)₂(Brpdm)₂(MeOH)₂](ClO₄)₂ [ 2 ], the Dy (III) ions of which have a NO₇ triangular dodecahedral coordination sphere. The two complexes show not only ferromagnetic interaction but also field‐induced single‐molecule magnet (SMM) behavior, which are rare Dy (III)‐containing cluster complexes with the NO₇ triangular dodecahedral coordination sphere that can show good magnetic relaxation. The energy barrier value of complex 2 is higher than those of complex 1 and the Dy (III) complexes with the DyNO₇ triangular dodecahedral coordination configuration reported in the literature.     

Coordination compounds of dysprosium(III) with 3-methyl-1-phenyl-4-formylpyrazol-5-one diacyldihydrazones

Coordination compounds of dysprosium(III) with diacyldihydrazones of saturated dicarboxylic acids, imino-, oxo-, and thiodiacetic acids, and 3-methyl-1-phenyl-4-formylpyrazol-5-one (H₄L) are described. [Dy₂(H₂L^O)₃] · 7.5CH₃OH · 3H₂O was subjected to X-ray diffraction analysis: space group \(R\bar 3\) , a = 17.349(1) Å, c = 65.669(4) Å, Z = 6, R = 0.076, R _w = 0.243 (5301 reflections with I ≥ 2σ(I)). The complex is established to have a binuclear structure and contain dysprosium ions linked via three bridging ligands. The coordination polyhedron of the Dy atom had a three-capped trigonal prism geometry. The magnetic properties of the synthesized complexes were studied.     

Three Phenoxo‐Bridged Dinuclear Lanthanide Complexes: Syntheses,Crystal Structures,and Magnetic Properties

Three dinuclear lanthanide complexes [Ln₂(H₂L)₂(NO₃)₄] [Ln = Dy ( 1 ), Tb ( 2 ), and Gd ( 3 )] [H₃L = 2‐hydroxyimino‐N′‐[(2‐hydroxy‐3‐methoxyphenyl)methylidene]‐propanohydrazone] were solvothermally synthesized by varying differently anisotropic rare earth ions. Single‐crystal structural analyses demonstrate that all the three complexes are crystallographically isostructural with two centrosymmetric Ln^III ions aggregated by a pair of monodeprotonated H₂L^– anions. Weak intramolecular antiferromagnetic interactions with different strength were mediated by a pair of phenoxo bridges due to superexchange and/or single‐ion anisotropy. Additionally, the Dy^III‐based entity shows the strongest anisotropy exhibits field‐induced single‐molecule magnetic behavior with two thermally activated relaxation processes. In contrast, 3 with isotropic Gd^III ion has a significant cryogenic magnetocaloric effect with the maximum entropy change of 25.7 J · kg^–1 · K^–1 at 2.0 K and 70.0 kOe.     

Copper(II) and Cadmium(II) Complexes Based on N,N‐Bis(3, 5‐dimethyl‐2‐hydroxybenzyl)‐N‐(2‐pyridylmethyl)amine Ligand: Syntheses,Structures, Magnetic,and Luminescent Properties

The reaction of the aryl‐oxide ligand H₂L [H₂L = N,N‐bis(3, 5‐dimethyl‐2‐hydroxybenzyl)‐N‐(2‐pyridylmethyl)amine] with CuSO₄ · 5H₂O, CuCl₂ · 2H₂O, CuBr₂, CdCl₂ · 2.5H₂O, and Cd(OAc)₂ · 2H₂O, respectively, under hydrothermal conditions gave the complexes [Cu(H₂L¹)₂] · SO₄ · 3CH₃OH ( 1 ), [Cu₂(H₂L²)₂Cl₄] ( 2 ), [Cu₂(H₂L²)₂Br₄] ( 3 ), [Cd₂(HL)₂Cl₂] ( 4 ), and [Cd₂(L)₂(CH₃COOH)₂] · H₂L ( 5 ), where H₂L¹ [H₂L¹ = 2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenol] and H₂L² [H₂L² = 2‐(2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenoxy)‐4, 6‐dimethylphenol] were derived from the solvothermal in situ metal/ligand reactions. These complexes were characterized by IR spectroscopy, elementary analysis, and X‐ray diffraction. A low‐temperature magnetic susceptibility measurement for the solid sample of 2 revealed antiferromagnetic interactions between two central copper(II) atoms. The emission property studies for complexes 4 and 5 indicated strong luminescence emission.     

Syntheses and structural determinations of the nine-coordinate rare earth metal: Na4[DyIII(dtpa)(H2O)]2·16H2O,Na[DyIII(edta)(H2O)3]·3.25H2O and Na3[DyIII(nta)2(H2O)]·5.5H2O

Three complexes, Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and Na₃[Dy^III (nta)₂(H₂O)]?·?5.5H₂O, have been synthesized in aqueous solution and characterized by FT–IR, elemental analyses, TG–DTA and single-crystal X-ray diffraction. Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O crystallizes in the monoclinic system with P2₁/n space group, a?=?18.158(10)?Å, b?=?14.968(9)?Å, c?=?20.769(12)?Å, β?=?108.552(9)°, V?=?5351(5)?ų, Z?=?4, M?=?1517.87?g?mol^?1, D _c?=?1.879?g?cm^?3, μ?=?2.914?mm^?1, F(000)?=?3032, and its structure is refined to R ₁(F)?=?0.0500 for 9384 observed reflections [I?>?2σ(I)]. Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O crystallizes in the orthorhombic system with Fdd2 space group, a?=?19.338(7)?Å, b?=?35.378(13)?Å, c?=?12.137(5)?Å, β?=?90°, V?=?8303(5)?ų, Z?=?16, M?=?586.31?g?mol^?1, D _c?=?1.876?g?cm^?3, μ?=?3.690?mm^?1, F(000)?=?4632, and its structure is refined to R ₁(F)?=?0.0307 for 4027 observed reflections [I?>?2σ(I)]. Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O crystallizes in the orthorhombic system with Pccn space group, a?=?15.964(12)?Å, b?=?19.665(15)?Å, c?=?14.552(11)?Å, β?=?90°, V?=?4568(6)?ų, Z?=?8, M?=?724.81?g?mol^?1, D _c?=?2.102?g?cm^?3, μ?=?3.422?mm^?1, F(000)?=?2848, and its structure is refined to R ₁(F)?=?0.0449 for 4033 observed reflections [I?>?2?σ(I)]. The coordination polyhedra are tricapped trigonal prism for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O and Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O, but monocapped square antiprism for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O. The crystal structures of these three complexes are completely different from one another. The three-dimensional geometries of three polymers are 3-D layer-shaped structure for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, 1-D zigzag type structure for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and a 2-D parallelogram for Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O. According to thermal analyses, the collapsing temperatures are 356°C for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, 371°C for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and 387°C for Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O, which indicates that their crystal structures are very stable.     

Syntheses,structural determination,and binding studies of nine-coordinate mononuclear (mnH)2[DyIII(Httha)]·3H2O and (enH2)3[DyIII(ttha)]2·9H2O

Two dysprosium coordination compounds, (mnH)₂[Dy^III(Httha)]·3H₂O (1) (H₆ttha?=?triethylenetetramine-N,N,N′,N″,N′′′,N′′′-hexaacetic acid and mn?=?methylamine) and (enH₂)₃[Dy^III(ttha)]₂·9H₂O (2) (en?=?ethylenediamine), were synthesized through direct heating and characterized by elemental analysis, FT-IR, thermal analysis, and single-crystal X-ray diffraction. X-ray diffraction analysis displays that 1 is a mononuclear nine-coordinate complex with a pseudo-monocapped square antiprismatic conformation (MCSAP) crystallizing in the monoclinic crystal system with P2(1)/c space group. The crystal data are as follows: a?=?16.1363(19)?Å, b?=?13.9336(11)?Å, c?=?13.6619(14)?Å, β?=?102.2490(10)°, and V?=?3001.8(5)?ų. There are two kinds of methylamine cation in 1. They connect [Dy^III(Httha)]^2?and crystal waters through hydrogen bonds, leading to formation of a 2-D ladder-like layer structure. The polymeric 2 also is a nine-coordinate structure with a pseudo-MCSAP crystallizing in the monoclinic crystal system with P2/c space group. The cell dimensions are: a?=?17.7801(16)?Å, b?=?9.7035(10)?Å, c?=?22.096(2)?Å, β?=?118.874(2)°, and V?=?3338.3(6)?ų. In 2 there are also two types of ethylenediamine cations. One connects three adjacent [Dy^III(ttha)]^3? complex anions through hydrogen bonds and the other is symmetrical forming hydrogen bonds with two neighboring [Dy^III(ttha)]^3? complex anions. These hydrogen bonds result in formation of a 2-D ladder-like layer structure as well.     

Rational Design of a Lanthanide‐Based Complex Featuring Different Single‐Molecule Magnets

The rational synthesis of the 2‐{1‐methylpyridine‐N‐oxide‐4,5‐[4,5‐bis(propylthio)tetrathiafulvalenyl]‐1H‐benzimidazol‐2‐yl}pyridine ligand ( L ) is described. It led to the tetranuclear complex [Dy₄(tta)₁₂( L )₂] ( Dy‐Dy₂‐Dy ) after coordination reaction with the precursor Dy(tta)₃?2 H₂O (tta^?=2‐thenoyltrifluoroacetonate). The X‐ray structure of Dy‐Dy₂‐Dy can be described as two terminal mononuclear units bridged by a central antiferromagnetically coupled dinuclear complex. The terminal N₂O₆ and central O₈ environments are described as distorted square antiprisms. The ac magnetism measurements revealed a strong out‐of‐phase signal of the magnetic susceptibility with two distinct sets of data. The high‐ and low‐frequency components were attributed to the two terminal mononuclear single‐molecule magnets (SMMs) and the central dinuclear SMM, respectively. A magnetic hysteresis loop was detected at very low temperature. From both structural and magnetic points of view, the tetranuclear SMM Dy‐Dy₂‐Dy is a self‐assembly of two known mononuclear SMMs bridged by a known dinuclear SMM.     

Insight into D6h Symmetry: Targeting Strong Axiality in Stable Dysprosium(III) Hexagonal Bipyramidal Single‐Ion Magnets

Following a novel synthetic strategy where the strong uniaxial ligand field generated by the Ph₃SiO^? (Ph₃SiO^?=anion of triphenylsilanol) and the 2,4‐di‐^tBu‐PhO^? (2,4‐di‐^tBu‐PhO^?=anion of 2,4‐di‐tertbutylphenol) ligands combined with the weak equatorial field of the ligand L^N6 , leads to [Dy^III(L^N6)(2,4‐di‐^tBu‐PhO)₂](PF₆) ( 1 ), [Dy^III(L^N6)(Ph₃SiO)₂](PF₆) ( 2 ) and [Dy^III(L^N6)(Ph₃SiO)₂](BPh₄) ( 3 ) hexagonal bipyramidal dysprosium(III) single‐molecule magnets (SMMs) with high anisotropy barriers of U_eff=973 K for 1 , U_eff=1080 K for 2 and U_eff=1124 K for 3 under zero applied dc field. Ab initio calculations predict that the dominant magnetization reversal barrier of these complexes expands up to the 3rd Kramers doublet, thus revealing for the first time the exceptional uniaxial magnetic anisotropy that even the six equatorial donor atoms fail to negate, opening up the possibility to other higher‐order symmetry SMMs.     

Hydrothermal Synthesis and Crystal Structure of One Rare Earth Substituted Keggin-Type Germanotungstate [Cu(en)2]2[Cu(en)2(H2O)]2H3{[Cu(en)2]2[Na2(H2O)1.75][K(H2O)3][Dy2(H2O)2 (GeW11O39)3]} · 6H2O

A novel germanotungstate derivative based on the dysprosium cation and monovacant Keggin anion, [Cu(en)₂]₂[Cu(en)₂(H₂O)]₂H₃{[Cu(en)₂]₂[Na₂(H₂O)_1.75][K(H₂O)₃][Dy₂(H₂O)₂(GeW₁₁O₃₉)₃]} · 6H₂O(en = ethylenediamine) 1, has been synthesized by hydrothermal method and characterized by elemental analysis, IR-UV spectroscopy, thermal analysis and single-crystal X-ray diffraction. In the compound, one kind of clusters with the Dy³⁺/[GeW₁₁O₃₉]^8? ratio of 2:3 was observed. Especially, the 2:3 type displays the novel cluster based on the rare earth and monolacunary Keggin polyoxometalate.     

Lanthanide(III) (Eu,Gd, Tb,Dy) Complexes Derived from 4‐(Pyridin‐2‐yl)methyleneamino‐1,2,4‐triazole: Crystal Structure,Magnetic Properties,and Photoluminescence

The reaction of lanthanide(III) nitrates with 4‐(pyridin‐2‐yl)methyleneamino‐1,2,4‐triazole (L) was studied. The compounds [Ln(NO₃)₃(H₂O)₃] ? 2 L, in which Ln=Eu ( 1 ), Gd ( 2 ), Tb ( 3 ), or Dy ( 4 ), obtained in a mixture of MeCN/EtOH have the same structure, as shown by XRD. In the crystals of these compounds, the mononuclear complex units [Ln(NO₃)₃(H₂O)₃] are linked to L molecules through intermolecular hydrogen‐bonding interactions to form a 2D polymeric supramolecular architecture. An investigation into the optical characteristics of the Eu³⁺‐, Tb³⁺‐, and Dy³⁺‐containing compounds ( 1 , 3 , and 4 ) showed that these complexes displayed metal‐centered luminescence. According to magnetic measurements, compound 4 exhibits single‐ion magnet behavior, with ΔE_eff/k_B=86 K in a field of 1500 Oe.     

Five Rare μ4‐O‐Centered Ln6 Clusters with Single‐Molecule Magnet Behavior for Dy6

Five hexanuclear lanthanide clusters of composition [Ln₆(μ₄‐O)₂(HCOO)₂L₄(HL′)₂(dmf)₂] [Ln=Dy ( 1 ), Er ( 2 ), Ho ( 3 ), Tb ( 4 ), Gd ( 5 ); H₂L=2‐{[2‐(hydroxymethyl)phenylimino]methyl}‐6‐methoxyphenol; H₃L′=3‐{[2‐(hydroxymethyl)phenylimino]methyl}benzene‐1,2‐diol; H₃L′ was derived in situ from the H₂L ligand] were prepared under solvothermal conditions. The [Ln₆] cores of 1 – 5 possess an unprecedented motif, namely, two tetrahedron Ln₄ units sharing an edge and two vertices. The six Ln^III ions of 1 – 5 are connected through two μ₄‐O anions. Magnetic susceptibility studies reveal that complex 1 exhibits frequency dependence of the alternating current susceptibility typical of single‐molecule magnets. Complex 1 possesses a relatively large energy barrier of 85 K among all of the reported Dy₆ single‐molecule magnets.