Magnetic Properties of the Layered Lanthanide Hydroxide Series YxDy8-x(OH)20Cl4·6H2O: From Single Ion Magnets to 2D and 3D Interaction Effects

Cinnamate-Intercalated Layered Yttrium Hydroxide: UV Light-Responsive Switchable Material

In recent years, there has been an increasing interest in stimuli-responsive host-guest materials due to the high potential for their application in switchable devices. Light is the most convenient stimulus for operating these materials; a light-responsive guest affects the host structure and the functional characteristics of the entire material. UV-transparent layered rare earth hydroxides intercalated with UV-switchable anions are promising candidates as stimuli-responsive host-guest materials. The interlayer distance in the layered rare earth hydroxides depends on the size of the intercalated anions, which could be changed in situ, e.g., via anion isomerisation. Nevertheless, for layered rare earth hydroxides, the possibility of such changes has not been reported yet. A good candidate anion that is capable of intercalating into the interlayer space is the cinnamate anion, which undergoes UV-assisted irreversible trans-cis isomerisation. In this work, both trans- and cis-cinnamate anions were intercalated in layered yttrium hydroxide (LYH). Upon UV-irradiation, the interlayer distance of trans-cinnamate-intercalated layered yttrium hydroxide suspended in isopropanol changed from 21.9 to 20.6 Å. For the first time, the results obtained demonstrate the possibility of using layered rare earth hydroxides as stimuli-responsive materials.

Multifunctionality of the [C2mim][Ln(fod)4] series (Ln = Nd–Tm except Pm): magnetic, luminescence and thermochemical studies

The [C2mim][Ln(fod)4] series presents a rare and reversible polymorphism, NIR and visible emission as well as SMM behavior. The varieties of physical behaviors make these compounds suitable for potential technological and/or biomedical applications.

All-Inorganic Single-Ion Magnets in Ceramic Matrices

All-inorganic single-ion magnets representing paramagnetic ions incorporated in a crystalline diamagnetic matrix are reviewed. Key results and advantages of this approach in comparison with the common strategy based on molecular metal-organic complexes are considered, and some unsolved problems and future perspectives are discussed.

Correlating magnetic anisotropy with [Mo(CN)7]4− geometry of MnII–MoIII magnetic frameworks

The magnetic coercivity of four new heptacyanomolybdate(iii)-based coordination polymers is correlated with the geometry of the [Mo^III(CN)₇]⁴⁻ anion and the cyanide bridging pattern of the framework.

A magnetic study of a layered lanthanide hydroxide family: Ln8(OH)20Cl4·nH2O (Ln = Tb, Ho, Er)

Three layered lanthanide hydroxides (LLHs), with the general formula Ln8(OH)20Cl4·nH2O (Ln = Tb (1), Ho (2), Er (3)), were prepared and magnetically characterized both as pure compounds and diluted within a yttrium diamagnetic matrix, LYH : xLn, LYH : 0.044Tb (1'), LYH : 0.045Ho (2'), and LYH : 0.065Er (3'). This study was complemented with theoretical calculations in order to understand the electronic configuration and the contributions to the slow relaxation behavior. In the pure compounds dominant 3D ferromagnetic interactions are observed, with a small magnetization hysteresis at 1.8 K for 1, while the magnetically diluted solid solutions display slow relaxation of magnetization at low temperatures.

Design and synthesis of metal hydroxide three-dimensional inorganic cationic frameworks

Three-dimensional (3D) cationic frameworks are rare but crucial host materials with vast industrial applications. However, the controlled synthesis of 3D inorganic cationic framework (ICF) materials still remains a challenge. Here, we develop a new strategy to construct 3D inorganic cationic frameworks by octahedral metal-hydroxide (M(OH)₆) unit induced reconstruction of layered rare-earth hydroxides. Based on this strategy, a large family (>187 members) of 3D-ICF with a general formula: RE₁₂(OH)₁₈((RE_1-x-y,M_xM'_y)(OH)₆)₄·ACl₆ (RE = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y; M = Al, Cr; M' = Mg, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn; A = Na, K) were achieved. This newly constructed strategy would greatly promote the development of 3D inorganic cationic materials. Furthermore, the discovery of this new family of cationic frameworks would pave the way for the potential application of cationic materials in different sorts of fields.

Sodalite-like rare-earth carbonates: a study of structural transformation and diluted magnetism

A series of novel rare earth carbonates, RE3(OH)6(CO3)Cl (RE = Dy, Er, Y), with sodalite-like (SOD-like) zeolite topologies have been successfully synthesized by introducing an appropriate amount of CO3(2-) from NaCO3 or atmospheric carbon dioxide as a template. Single-crystal X-ray diffraction reveals that the structure consists of the RE3(OH)6(3+) cationic framework with a SOD-like topology built from vertex-sharing [RE4(μ3-OH)4] cubes. The CO3(2-) anions seal the 6-ring opening and Cl(-) anions situated in the channels to achieve charge balance. After calcination at 370 °C, the compound RE3(OH)6(CO3)Cl in situ transforms into a new phase formulated as RE3O4Cl. Interestingly, the structure of RE3O4Cl represents a new SOD-like open framework, associated with the removal of the CO3(2-) from RE3(OH)6(CO3)Cl. The samples are characterized by thermogravimetric analysis (TGA), elemental analysis, X-ray photoelectron spectroscopy and magnetic studies. Furthermore, single-molecule magnet behaviours can be observed for the diluted samples of Dy0.0068Y2.9932(OH)6(CO3)Cl and Dy0.0068Y2.9932O4Cl with a Dy/Y molar ratio of up to 1/440 as well as Er0.19Y2.81(OH)6(CO3)Cl with an Er/Y ratio of 1/15, showing dominant single-ion effects.

Coherence and organisation in lanthanoid complexes: from single ion magnets to spin qubits

Molecular magnetism is reaching a degree of development that will allow for the rational design of sophisticated systems.

Dodenuclear [Mn(III)(8)Ln(III)(4)] clusters with 2-(hydroxymethyl)pyridine: syntheses, structures, and magnetic properties

A new family of isostructural Mn/Ln dodenuclear clusters: [Mn8Ln4(O)8(hmp)4(O2CPh)12(NO3)4(PhCO2H)(C2H5OH)] [Ln = La (1), Pr (2), Nd (3), Gd (4), Dy(5), hmpH = 2-(hydroxymethyl)pyridine] have been synthesized by the reaction of Mn(NO3)2 and Ln(NO3)3·6H2O with hmpH and benzoic acid as co-ligands. Compounds 1-5 possess a spindle-shaped core of [MnLn(μ4-O)4(μ3-O)4(μ3-OR)2(μ2-OR)8](10+), which is composed of six face-sharing defected cubane units and two square-pyramidal units. The compounds represent the highest nuclearity Mn/Ln clusters with the use of hmpH to date. That the ferromagnetic interactions dominated within complexes 1-4 were suggested by solid-state dc magnetic susceptibility analyses. Compound 4 displays a magnetic-caloric effect (MCE) with 13.94 J kg(-1) K(-1) as the entropy change at 6 K for ΔH = 8 T. Compounds 1 and 5 exhibit an out-of-phase χ''M peak maximum above 2.0 K. Fitting of the ac susceptibility data to an Arrhenius law gives an energy barrier Ueff = 6.88/7.44 K for compounds 1 and 5 respectively.

Modeling the magnetic properties of lanthanide complexes: relationship of the REC parameters with Pauling electronegativity and coordination number

In a previous study, we introduced the Radial Effective Charge (REC) model to study the magnetic properties of lanthanide single ion magnets. Now, we perform an empirical determination of the effective charges (Zi) and radial displacements (Dr) of this model using spectroscopic data. This systematic study allows us to relate Dr and Zi with chemical factors such as the coordination number and the electronegativities of the metal and the donor atoms. This strategy is being used to drastically reduce the number of free parameters in the modeling of the magnetic and spectroscopic properties of f-element complexes.

Layered gadolinium hydroxides for low-temperature magnetic cooling

A 2D gadolinium hydroxide with a large magnetocaloric effect is an excellent candidate for cryogenic magnetic refrigeration.

Layered gadolinium hydroxides have revealed to be excellent candidates for cryogenic magnetic refrigeration. These materials behave as pure 2D magnetic systems with a Heisenberg–Ising critical crossover, induced by dipolar interactions. This 2D character and the possibility offered by these materials to be delaminated open the possibility of rapid heat dissipation upon substrate deposition.