Temperature Below 30 mK Achieved by Adiabatic Demagnetization Refrigeration.

Adiabatic demagnetization refrigeration (ADR) is the only technique capable of reaching ultralow temperatures without helium-3 and plays a crucial role at the forefront of both fundamental and applied science. However, progress in ADR is constrained by the limited magnetic entropy change (-Δ) of existing refrigerants at ultralow temperatures. This limitation primarily stems from the inherent contradiction of simultaneously attaining a large -Δ and a low magnetic ordering temperature () in magnetic refrigerant design.

84-Nuclearity Lanthanide-Aluminum Cyclic Clusters: Promising Materials for Iodine Capture and Storage.

Developing high-performance adsorbents for iodine uptake and storage has become an urgent priority for safe disposal and long-term storage of nuclear waste. In this work, two cyclic lanthanide-aluminum clusters with the formula [LnAl(hmp)(CHO)(μ-OH)(μ-OH)(HO)]Cl·(NO)·(HO) (Ln = Tb, ≈ 80, ; Ln = Gd, ≈ 100, ; Hhmp = 2-(hydroxymethyl)pyridine and CHO = ethylene glycol) are reported. Single-crystal analysis reveals that its inner diameter is approximately 1.

Exceptional Cooling Capacity of LiGdYbF at Sub-Kelvin Temperatures.

Adiabatic demagnetization refrigeration, which utilizes the magnetocaloric effect of magnetic refrigerants, stands as the sole cooling technology capable of achieving sub-Kelvin temperatures efficiently and reliably without relying on scarce He resources or gravity. However, current sub-Kelvin magnetic refrigerants encounter challenges such as structural instability in vacuum or under mild heating, along with small magnetic entropy change (-ΔS) values, which significantly limit their practical applications. Here a water-free magnetic refrigerant, LiGdYbF is reported, prepared by introducing Li⁺ ions to reduce the dipolar interactions between Gd ions and/or Yb ions.

High-Nuclearity LnAl Clusters: Neonates of Open Hollow Dodecahedral Cage Families.

Open hollow dodecahedral cage clusters have long been a coveted target in synthetic chemistry, yet their creation poses immense challenges. Here we report two open hollow dodecahedral lanthanide-aluminum (Ln-Al) heterometallic cage clusters, namely, [LnAl(μ-OH)(μ-OH)(OAc)(HO)](ClO)·(MeCN)·(HO), (Ln = Dy and = 27, = 300 for ; Ln = Y and = 28, = 420 for ). Remarkably, the 350 metal atoms in and display a Keplerate-type four-shell structure of truncated icosidodecahedron@dodecahedron@dodecahedron@icosidodecahedron.

Achieving Magnetic Refrigerants with Large Magnetic Entropy Changes and Low Magnetic Ordering Temperatures.

Adiabatic demagnetization refrigeration (ADR) is a promising cooling technology with high efficiency and exceptional stability in achieving ultralow temperatures, playing an indispensable role at the forefront of fundamental and applied science. However, a significant challenge for ADR is that existing magnetic refrigerants struggle to concurrently achieve low magnetic ordering temperatures () and substantial magnetic entropy changes (-Δ) at ultralow temperatures. In this work, we propose the combination of Gd and Yb to effectively regulate both -Δ and in ultralow temperatures.

pH-Driven Rotational Configuration of Keggin-Fe Clusters and Their Transformations.

Keggin-Fe clusters are considered foundational building blocks or prenucleation precursors of ferrihydrite. Understanding the factors that influence the rotational configuration of these clusters, and their transformations in water, is vital for comprehending the formation mechanism of ferrihydrite. Here, we report syntheses and crystal structures of four lanthanide-iron-oxo clusters, namely, [DyFe(Gly)(μ-OH)(μ-OH)(μ-O)(HO)]·13ClO·19HO (), [DyFe(Gly)(μ-OH)(μ-O)(HO)]·13ClO·14HO (), [PrFe(Gly)(μ-OH)(μ-O)(μ-O)(HO)]·6ClO·20HO (), and [PrFe(Gly)(μ-OH)(μ-O)(HO)]·13ClO·22HO (, Gly = glycine).

Accurate Prediction of the Magnetic Ordering Temperature of Ultralow-Temperature Magnetic Refrigerants.

Adiabatic demagnetization refrigeration is known to be the only cryogenic refrigeration technology that can achieve ultralow temperatures (≪1 K) at gravity-free conditions. The key indexes to evaluate the performance of magnetic refrigerants are their magnetic entropy changes (-Δ) and magnetic ordering temperature (). Although, based on the factors affecting the -Δ of magnetic refrigerants, one has been able to judge if a magnetic refrigerant has a large -Δ, how to accurately predict their remains a huge challenge due to the fact that the of magnetic refrigerants is related to not only magnetic exchange but also single-ion anisotropy and magnetic dipole interaction.

Magneto-optical Properties of Chiral CoLn and CoLn (Ln = Dy and Er) Clusters.

A series of chiral heterometallic Ln-Co clusters, denoted as and (Ln = Dy and Er), were synthesized by reacting the chiral chelating ligand (/)-2-(1-hydroxyethyl)pyridine (Hmpm), CoAc·4HO, and Ln(NO)·6HO. and exhibit perfect mirror images in circular dichroism within the 320-700 nm range. Notably, the and clusters display pronounced magnetic circular dichroism (MCD) responses of the hypersensitive f-f transitions I-G at 375 nm and I-H at 520 nm of Er ions.

Single-molecule magnet behavior in heterometallic decanuclear [LnFe] (Ln = Y, Dy, Ho, Tb, Gd) coordination clusters.

Five decanuclear lanthanide-iron clusters, formulated as [LnFe(hmp)(μ-OH)(μ-OH)(μ-O)(HO)]·6ClO·HO ( ≈ 8, Ln = Y for 1; ≈ 6, Ln = Dy for 2; ≈ 6, Ln = Ho for 3; ≈ 7, Ln = Tb for 4; ≈ 7, Ln = Gd for 5, Hhmp = 2-(hydroxymethyl)pyridine), have been synthesized and structurally characterized. Single-crystal structural analysis reveals that the cluster consists of six face-sharing defective cubane units. Dynamic magnetic investigations indicated that cluster 2 exhibits single-molecule magnet behavior under a zero dc field eliciting an effective energy barrier of = 17.

Functionalization of Keggin Fe-Oxo Clusters.

Two Keggin Fe-oxo clusters, [PrFe(NO)(L-van)(D-van)(TEOA)(μ-OH)(μ-OH)(μ-O)(HO)]·(ClO)·(NO)·10HO () and [DyFe(NO)(L-van)(D-van)(TEOA)(μ-OH)(μ-OH)(μ-O)(HO)]·(ClO)·(NO)·15HO (), where L-van = l-valine, D-van = d-valine, and TEOA = triethanolamine, were prepared by using Ln as a stabilizer. Cluster crystallizes in a chiral space group of 2, while cluster crystallizes in a centrosymmetric space group of . Dynamic magnetic measurements of under a zero direct-current field reveal that exhibits single-molecule-magnet characteristics with an energy barrier of 18.

Role of the Auxiliary Ligand in the Spontaneous Resolution of Enantiomers in Three-Dimensional Coordination Polymers.

Four pairs of chiral 3D coordination polymers (CPs), [Zn(BDC)(lac)(DMF)]·guest () (HBDC = benzene dicarboxylic acid; Hlac = lactic acid; guest = 1.5DMF + -PrOH), [Co(BDC)(lac)(DMF)]·guest () (guest = DMF + 2HO), [Fe(BDC)(lac)(DMF)](CO)·guest () (guest = DMF + 2HO), and {Zn(BPDC)(lac)[NH(CH)]}·guest (HBPDC = 3,3'-biphenyldicarboxylic acid; guest = 6DMF + 18HO) (), are prepared through the reactions of racemic lactic acid (-Hlac) with different metal ions and auxiliary ligands. Structural analyses and DFT calculations reveal that forming more and stronger coordination bonds between the auxiliary ligand and metal ions is more conducive to the spontaneous resolution of enantiomers in 3D CPs than simply increasing the entropy of the auxiliary ligand itself.

Capturing Lacunary Iron-Oxo Keggin Clusters and Insight Into the Keggin-Fe Cluster Rotational Isomerization.

The formation mechanism of ferrihydrite is the key to understand its treatment of pollutants in waste water and purification of surface water and groundwater. Although emerging evidence suggests that formation of the ferrihydrite occurs through the aggregation of prenucleation clusters, rather than classical atom-by-atom growth, its formation mechanism remains unclear. Herein, an iron-oxo anionic cluster of [Fe (μ -O) (μ -OH) (μ -OH) (CH COO) (H O) ] viewed as a dimer of bivacant β-Keggin-Fe clusters was for the first time obtained by using lanthanide ions as stabilizers.

Mini-Review: The Non-Immune Functions of Toll-Like Receptors.

Toll-like receptors (TLRs) are a family of highly conserved pattern recognition receptors that can recognize both pathogen-associated molecular patterns and danger-associated molecular patterns. These receptors are important in the activation of the innate immune system and play a role in shaping the adaptive immune system. For years, the expression of TLRs in the brain has been proposed to contribute to the immunological protection of the central nervous system.

Edaravone, a free radical scavenger, protects neuronal cells' mitochondria from ischemia by inactivating another new critical factor of the 5-lipoxygenase pathway affecting the arachidonic acid metabolism.

To investigate the neuroprotective effect of edaravone was dependent on 5-lipoxygenase (5-LOX) signalling pathway or not. Middle cerebral artery occlusion (MCAO) and oxygen glucose deprivation (OGD) were established in SD rats and PC12 cells to mimic ischemic injury. In vivo, edaravone can significantly reduce neurological deficit scores, infarct volume, ROS level and expression of 5-LOX.