Dy Analogue Research Articles

Urothermal synthesis of mononuclear lanthanide compounds: slow magnetization relaxation observed in Dy analogue

Two mononuclear compounds Ln(e-urea)8(NO3)3 (Ln = Dy(1) and Tb(2)) have been urothermally synthesized by using the ethyleneurea (e-urea) as an organic ligand and a solvent. The e-urea ligand with a single donor atom is a unique ligand for coordinating to lanthanide ions, which is very different from those commonly observed polytopic ligands with suitable coordination pockets to encapsulate lanthanide(III) ions or chelating organic ligands. The lanthanide center surrounded by eight e-urea ligands is in a square antiprismatic environment with an approximate D4d local symmetry. Magnetic properties of both compounds have been investigated in detail using direct-current and alternating-current susceptibility measurements. The Dy(1) analogue displays slow magnetic relaxation behavior with an effective energy barrier of the magnetic relaxation of 37.68 K and the pre-exponential factor τ0 of 1.47 × 10−9 s in the presence of direct-current field of 2 kOe.

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.

Exchange Coupling and Its Chemical Trend Studied by High-Frequency EPR on Heterometallic [Ln2Ni] Complexes

We applied high-frequency electron paramagnetic resonance to trinuclear 4f-3d heterometallic complexes, [{Ln(hfac)3}2{Ni(dpk)2(py)2}] (Ln = Y, Gd, Tb, and Ho; hfac = hexafluoroacetylacetonate, dpk = di-2-pyridyl ketoximate, and py = pyridine), and determined the exchange parameter J(Ln-Ni) as well as nickel(II) zero-field splitting parameters. In contrast to the antiferromagnetic Dy analogue, ferromagnetic couplings were precisely characterized as J(Gd-Ni)/kB = +0.301(4) K, J(Tb-Ni)/kB = +0.216(12) K, and J(Ho-Ni)/kB = +0.110(3) K (defined as -J(Ln-Ni)∑J(Ln)(z)S(Ni)).

Family of Mixed 3d–4f Dimeric 14-Metallacrown-5 Compounds: Syntheses, Structures, and Magnetic Properties

An isomorphous family of mixed 3d-4f dodenuclear aggregates, {[Mn(III)8Ln4(Clshi)8(OAc)6(μ3-OCH3)2(μ3-O)2(CH3OH)12(H2O)2]·4CH3OH·xH2O)} (where Ln = Eu(III) (1), Gd(III) (2), Tb(III) (3), and Dy(III) (4); ClshiH3 = 5-chlorosalicylhydroxamic acid; x = 5 for 1 and 3; x = 6 for 2; x = 2 for 4), were synthesized and characterized. They were obtained from the reaction of ClshiH3 with Mn(OAc)2·4H2O and Ln(NO3)3·6H2O. These isomorphous mixed 3d-4f compounds represent a family of novel structures with lanthanide ions in the metallacrown (MC) ring. Each dodecanuclear aggregate contains two offset stacked 14-MC-5 units with M-N-O-M-N-O-Ln-O-N-M-O-N-M connectivity to capture one Ln(III) ion in the core of each MC. Two 14-MC-5 units are connected through O ions with four Mn ions and six O atoms arranged in a double Mn4O6 cubane. Magnetic measurement indicates that antiferromagnetic interactions are present between the metal ions. The Dy(III) analogue with high anisotropy and large spin shows slow magnetization relaxation at a direct-current field of 2 kOe.

Lanthanide Dinuclear Complexes Involving Tetrathiafulvalene-3-pyridine-N-oxide Ligand: Semiconductor Radical Salt, Magnetic, and Photophysical Studies

Centro-symmetric dinuclear complexes of formula [Ln(tta)(3)(L)](2)·xCH(2)Cl(2), (tta(-) = 2-thenoyltrifluoroacetonate anion, x = 0.5 for Ln = Eu (1a), Tb (3), and Dy (4) and x = 0 for Ln = Eu (1b) and Nd (2)) have been synthesized using the tetrathiafulvalene-3-pyridine-N-oxide as a bridging ligand (L). X-ray structures have shown the formation of channels with CH(2)Cl(2) solvent inside. 1 is stable with both filled channels (at 150 K) and empty channels (at room temperature). The Dy(III) analogue displays a complex butterfly like hysteresis loop at 1.5 K. Photophysical properties of the coordination complexes have been studied by solution and solid-state absorption spectroscopy. Time-dependent density functional theory (TD-DFT) calculations have been carried out on the diamagnetic Y(III) derivative to shed light on the absorption spectrum. For 2, the excitation of the charge transfer transitions induces line shape emission in the near-infrared spectral range assigned to (4)F(3/2) → (4)I(9/2), (4)F(3/2) → (4)I(11/2), and (4)F(3/2) → (4)I(13/2) neodymium centered transitions. The reversible redox-activity of the ligand L makes possible an original sensitization process involving a ligand centered charge separation followed by energy transfer to the Nd(III) ion upon recombination.

Slow magnetic relaxation in radical cation tetrathiafulvalene-based lanthanide(iii) dinuclear complexes

Lanthanide dinuclear complexes involving tetrathiafulvalene-based ligands in their radical cation form were synthesised and crystallised by a galvanostatic procedure. Dynamic magnetic measurements reveal an unprecedented slow magnetic relaxation for the Dy(III) analogue in this kind of molecular edifice.

Heterometallic Tetranuclear [LnIII2CoIII2] Complexes Including Suppression of Quantum Tunneling of Magnetization in the [DyIII2CoIII2] Single Molecule Magnet

Using a heterometallic approach the synthesis, structures, and magnetic properties are reported for the complexes [Ln(III)(2)Co(III)(2)(OMe)(2)(teaH)(2)(O(2)CPh)(4)(MeOH)(4)](NO(3))(2)·MeOH·H(2)O {Ln = Gd (1a), Tb (2a), and Dy (3a)} and [Ln(III)(2)Co(III)(2)(OMe)(2)(teaH)(2)(O(2)CPh)(4)(MeOH)(2)(NO(3))(2)]·MeOH·H(2)O {Ln = Gd (1b), Tb (2b), and Dy (3b)}. Both compounds for the respective lanthanide ions are found to be isolated within the same crystal. Each Ln(III) dinuclear unit is incorporated within a diamagnetic Co(III)/organic ligand backbone utilizing triethanolamine and benzoic acid as bridging ligands. Magnetic studies reveal an absence of any observable coupling interaction for the Gd case. The Dy analogue displays single molecule magnet (SMM) behavior with a large energy barrier to magnetization reversal of 88.8 K, and the quantum tunneling of the magnetization (QTM) is effectively suppressed because of the nonmagnetic exchange ground state of the molecule. Dilution of the Dy complex into an isostructural diamagnetic yttrium matrix allowed us to determine aspects of the relaxation mechanism within the system.

Nitrate-Bridged “Pseudo-Double-Propeller”-Type Lanthanide(III)–Copper(II) Heterometallic Clusters: Syntheses, Structures, and Magnetic Properties

Two discrete nitrate-bridged novel "pseudo-double-propeller"-shaped hexanuclear Cu/Ln clusters of the formula [Cu(4)Ln(2)L(4)L'(4)(NO(3))(2)(OH(2))(2)]·3NO(3)·4H(2)O [Ln = Dy, Gd; LH = o-vanilin; L'H = 2-(hydroxyethyl)pyridine] were synthesized and characterized. Single-crystal X-ray diffraction studies revealed the trimeric half-propeller-type Cu(2)/Ln core connected to other opposite-handed similar trimers by a bridging nitrate ligand. The Dy analogue, [Cu(4)Dy(2)L(4)L'(4)(NO(3))(2)(OH(2))(2)]·3NO(3)·4H(2)O, shows frequency-dependent out-of-phase alternating-current magnetic susceptibility, which indicates that this novel discrete [Cu(4)Dy(2)] heterometallic cluster may exhibit single-molecule-magnet behavior.

Synthesis and Properties of New Multinary Silicides R5Mg5Fe4AlxSi18–x (R = Gd, Dy, Y, x ≈ 12) Grown in Mg/Al Flux

Reactions of iron, silicon, and R = Gd, Dy, or Y in 1:1 Mg/Al mixed flux produce well-formed crystals of R(5)Mg(5)Fe(4)Al(x)Si(18-x) (x ≈ 12). These phases have a new structure type in tetragonal space group P4/mmm (a = 11.655(2) Å, c = 4.0668(8) Å, Z = 1 and R(1) = 0.0155 for the Dy analogue). The structure features two rare earth sites and one iron site; the latter is in monocapped trigonal prismatic coordination surrounded by silicon and aluminum atoms. Siting of Al and Si was investigated using bond length analysis and (27)Al and (29)Si MAS NMR studies. The magnetic properties are determined by the R elements, with the Gd and Dy analogues exhibiting antiferromagnetic ordering at T(N) = 11.9 and 6.9 K respectively; both phases exhibit complex metamagnetic behavior with varying field.

Structural and magnetic characterization of Ho3SbO7 and Dy3SbO7

We present an experimental investigation of the structural and magnetic properties of Ho3SbO7 and Dy3SbO7. These compounds adopt the Y3TaO7 structure, space group C2221. The magnetic rare-earth ions occupy an intricate lattice related to the pyrochlore lattice that occurs in Ho2Ti2O7 and Dy2Ti2O7. The crystal structure of Ho3SbO7 is determined by Rietveld refinement of the powder X-ray diffraction pattern at ambient temperature, and that of the Dy analogue is inferred to be similar. Magnetic susceptibility measurements show that Ho3SbO7 and Dy3SbO7 have negative Curie–Weiss temperatures: –8.4 K (Ho) and –9.2 K (Dy). Magnetic transitions have been detected at 2.0 K (Ho) and 3.0 K (Dy). We discuss the results in terms of the ``dipolar spin ice model'' that has been used to describe Ho2Ti2O7 and Dy2Ti2O7. PACS Nos.: 75.25+z, 75.50Ee, 61.10Nz

Lanthanide complexes with O2PH2?, O2P(CH2Cl)2?and O2P(CH2OH)2?ligands: a solid-state tubular micelle

Attempts were made to synthesise lanthanide complexes of phosphorus-based ligands so as to incorporate channels which might act as hosts for small molecules; the sharing of ligands in La(O2P(CH2Cl)2)3(OP(OH)(CH2Cl)2) is between adjacent metals, resulting in a linear stacking arrangement rather than a lattice. Pr(O2P(CH2OH)2)3 crystallises into a highly H-bonded lattice, in which the methylene groups are spontaneously directed so as to line channels oriented along one of the crystal axes in a fashion reminiscent of solution micelles. These channels are, however, apparently too small to accommodate aliphatic hydrocarbons. The structure of Ho(O2PH2)3, which is the same as that of its prototypal Dy analogue, is also pictured and described