Homochiral DyZn zero-field single-molecule magnets derived from ()/()-2-methoxy-2-phenylacetic acids.

Despite the unique advantages of multifunctional integration at the nanoscale, chiral zero-field single-molecule magnets (SMMs), especially those based on homochiral carboxylic acids, are still difficult to obtain. Herein, homochiral ()/()-2-methoxy-2-phenylacetic acids (-HMPA)/(-HMPA) were selected as the bridging ligands to assemble a pair of DyZn enantiomers based on the Schiff base ligand ()-2-((2-hydroxy-3-methoxybenzylidene)amino)phenol (HL), [DyZn(-MPA)(L)(DMF)]·2DMF (-1) (DMF = ,-dimethylformamide) and [DyZn(-MPA)(L)(DMF)]·2DMF (-1), which possess a [DyZnO] defective dicubane core. The CD spectra of -1 and -1 confirmed their enantiomeric nature and chiral optical activities.

Magnetic anisotropy of dysprosium encapsulated metallofullerene molecules: a theoretical study.

A series of metallofullerene single-ion magnets embedded with [DyO] and [DyO] fragments were designed to probe the magnetic anisotropies and magnetic relaxation mechanisms using complete-active-space self-consistent field (CASSCF) calculations. CASSCF calculations showed that fullerenes with different diameters exert marginally varying influences on both the quantum tunneling of magnetization and energy level splitting, ultimately causing changes in energy barriers. Notably, [DyO] encapsulated in the fullerenes of C shows the best behavior.

Coupling Dy toroics in macrocycles.

A Dy complex with centrosymmetric edge-to-edge assembly of Dy triangles showing toroidal arrangement of the magnetic moments was encapsulated in a macrocycle.

Chiral Pseudo- Dy(III) Single-Molecule Magnet Based on a Hexaaza Macrocycle.

A mononuclear complex [Dy(phenN)(HL')]PF·CHCl (HL' = /-1,1'-binaphthyl-2,2'-diphenol) with local symmetry was synthesized. Structural determination shows that Dy was encapsulated within the coordination cavity of the neutral hexaaza macrocyclic ligand phenN, forming a non-planar coordination environment. The axial positions are occupied by two phenoxy groups of binaphthol in the form.

How to Obtain the Blocking Energy Barrier of a Co Adatom on a Single MgO Layer: A Theoretical Exploration.

Co adatoms deposited on a single MgO layer have been reported to exhibit a record-high zero-field splitting of 58 meV (467.8 cm). However, their effective blocking energy barrier is almost zero considering the much slower spin relaxation time on the order of 10 s at 0.

Homochiral Dy zero-field single-molecule magnets derived from axial chiral ligands ()/()-octahydro-1,1'-bi-2-naphthyl phosphate.

The construction of homochiral zero-field single-molecule magnets (SMMs), especially with axial chiral ligands, remains a great challenge. Herein the first examples of homochiral Dy(III) Schiff base complexes based on axial chiral ligands ()/()-5,5',6,6',7,7',8,8'-octahydro-1,1'-bi-2-naphthyl phosphate (-HL/-HL), [Dy(-L/-L)(L)(HO)(MeOH)]·2MeOH·CHCl·2MeCN·2HO (-1/-1) [HL = ()-'-(5-fluoro-2-hydroxybenzylidene)pyrazine-2-carbohydrazide], were synthesized at room temperature, which show ferromagnetic coupling and act as zero-field SMMs, with a / value of 61 K at 0 Oe. calculations were used to explain their magnetic interaction and magnetic relaxation properties.

Synergism of Light-Induced [4 + 4] Cycloaddition and Electron Transfer Toward Switchable Photoluminescence and Single-Molecule Magnet Behavior in a Dy Cubane.

Molecular materials possessing switchable magneto-optical properties are of great interest due to their potential applications in spintronics and molecular devices. However, switching their photoluminescence (PL) and single-molecule magnet (SMM) behavior via light-induced structural changes still constitutes a formidable challenge. Here, a series of cubane structures were synthesized via self-assembly of 9-anthracene carboxylic acid (HAC) and rare-earth ions.

Constructing high axiality mononuclear dysprosium molecular magnets a regulation-of-co-ligands strategy.

Two lanthanide complexes with formulae [Dy(L)(pentafluoro-PhO)] (1) and [Dy(L)(2,6-difluoro-PhO)](BPh) (2) (L = 2,14-dimethyl-3,6,10,13,19-pentaazabicyclo[13.3.1]nonadecal (19),2,13,15,17-pentaene) were structurally and magnetically characterized.

Effect of coordinated anions on ferromagnetically coupled Dy zero-field single-molecule magnets.

A new hydrazone Schiff base ligand was condensed from 2-hydroxy-3-methoxybenzaldehyde and pyrimidine-4-carbohydrazide {HL = ()-'-(2-hydroxy-3-methoxybenzylidene)pyrimidine-4-carbohydrazide}, which was used to assemble two new Dy complexes DyL(DMF)(NO) (1) and DyL(DMF)(AcO) (2). Notably, the coordinated anions have a subtle effect on the coordination configurations of the Dy ions and the magnetic properties of the two Dy complexes. The Dy ions in 1 and 2 have the same NO coordination environment but show the triangular dodecahedron and the biaugmented trigonal prism coordination configurations, respectively.

Magnetodielectric Effect in a Triangular Dysprosium Single-Molecule Toroics.

Single-molecule toroics are molecular magnets with vortex distribution of magnetic moments. The coupling between magnetic and electric properties such as the magnetodielectric effect will provide potential applications for them. Herein, the observation of significant magnetodielectric effect in a triangular Dy3 crystal with toroidal magnetic moment and multiple magnetic relaxations is reported.

The influence of light on the field-induced magnetization dynamics of two Er(III) coordination polymers with different halogen substituents.

Photocontrolled magnetic properties are fundamental for the applications of molecular magnets, which have the features of high time and space resolution; however, such magnetic properties are highly challenging to be achieved owing to the weak light-matter interactions. Herein, the influence of light irradiation on the field-induced magnetization dynamics of two Er(III) coordination polymers 1 and 2 with the same coordination skeletons but different halogen substituents was studied. 1 and 2, and their photoexcited products 1a and 2a, display field-induced magnetization dynamics based on Orbach and/or Raman processes.

Reversible single-crystal to single-crystal transformation between triangular single-molecule toroics.

We report a method for synthesizing single-molecule magnets through a single-crystal to single-crystal transformation. This process yields two single-molecule magnets with similar triangular Dy cores but distinct solvents and space groups achieved solvent exchange. Magnetic properties reveal that both Dy molecules exhibit similar toroidal moments but manifest diverse multiple magnetization dynamic behaviors owing to the spin-lattice coupling influence from different solvent molecules.

Protein Containing the GGDEF Domain Affects Motility and Biofilm Formation in and is Negatively Regulated by Fur and HapR.

Objective: This study aimed to investigate whether the VCA0560 gene acts as an active diguanylate cyclase (DGC) in and how its transcription is regulated by Fur and HapR.

Methods: The roles of VCA0560 was investigated by utilizing various phenotypic assays, including colony morphological characterization, crystal violet staining, Cyclic di-GMP (c-di-GMP) quantification, and swimming motility assay. The regulation of the VCA0560 gene by Fur and HapR was analyzed by luminescence assay, electrophoretic mobility shift assay, and DNase I footprinting.

Promoted Photocatalytic Hydrogen Evolution by Tuning the Electronic State of Copper Sites in Metal-Organic Supramolecular Assemblies.

The electronic state in terms of charge and spin of metal sites is fundamental to govern the catalytic activity of a photocatalyst. Herein, we show that modulation of the electronic states of Cu sites, without changing the coordination environments, of two metal-organic supramolecular assemblies based on π⋅⋅⋅π stacking can significantly improve photocatalytic activity. The use of these heterogeneous photocatalysts, without using noble metal cocatalysts, resulted in an increase of the hydrogen production rate from 522 to 3620 μmol h  g .

Ferromagnetically coupled single-chain magnets exhibiting a magnetic hysteresis of 0.42 Tesla in cyano-bridged FeIII2M (M = Ni, Fe) coordination polymers.

The synthesis, single-crystal structures and magnetic properties of two new double-zigzag-chain cyano-bridged heterobimetallic {[M(Py-NOH)][Fe(Tp*)(CN)]}·HO ([FeIII2M]) (Py-NOH = 4-pyridinealdoxime, Tp* = tris(3,5-dimethylpyrazol-1-yl)borohydride, M = Ni (1), Fe (2)) compounds are reported. The crystal structures of both compounds were determined by single-crystal X-ray diffraction. Complexes 1 and 2 are isostructural, with the crystal structure comprising neutral double-zigzag (4,2-ribbon-like) bimetallic chains.

Alkyl Chains Modulated Magnetization Dynamics of Mononuclear Trigonal Prismatic Co Complexes.

Four benzeneboron-capped mononuclear Co complexes with different alkyl substitutions on the fourth position of phenylboronic acid were obtained. The Co ions are all wrapped by the pocket-like ligands and located in trigonal prismatic coordination geometries. Alternating-current magnetic susceptibility measurements reveal that they show different magnetization dynamics, such as distinct relaxation rates at the same temperature, the faster QTM rates for the ethyl and propyl substituted complexes, as well as different relaxation processes.

Boosting the mono-axial crystal field in stable high-coordinate Dy(III) single-ion magnets by substitution of the phenoxy axial ligand.

Synthesis of air-stable and high-performance single-molecule magnets (SMMs) is challenging. Here, a heptadentate pentapyridyldiamine (BPA-TPA) ligand and fine-tuned axial phenoxy ligands are used to synthesize two triangular dodecahedral Dy(III) complexes [Dy(BPA-TPA)(4-methoxy-PhO)](BPh)·3CHCl (4) and [Dy(BPA-TPA)(2,4-dimethyl-PhO)](BPh)·0.85CHCl (5).

Regulating Magnetic Relaxations of Cyano-Bridged {Dy Mo } Systems by Tuning the N-Sites in β-Diketone Ligands.

Cyano-bridged 4d-4f molecular nanomagnets have re-called increasing research interests in molecular magnetism since they offer more possibilities in achieving novel nanomagnets with versatile structures and magnetic interactions. In this work, four β-diketone ligands bearing different substitution N-sites were designed and synthesized, namely 1-(2-pyridyl)-3-(3-pyridyl)-1,3-propanedione (HL ), 1,3-Bis (3-pyridyl)-1,3-propanedione (HL ), 1-(4-pyridyl)-3-(3-pyridyl)-1,3-propanedione (HL ), and 1,3-Bis (4-pyridyl)-1,3-propanedione (HL ), to tune the magnetic relaxation behaviors of cyano-bridged {Dy Mo } systems. By reacting with DyCl  ⋅ 6H O and K Mo(CN)  ⋅ 2H O, four cyano-bridged complexes, namely {[Dy[Mo (CN) ](HL ) (H O) ]} ⋅ 6H O (1), {[Dy[Mo (CN) ](HL )(H O) (CH OH)]}  ⋅ 2CH OH ⋅ 3H O (2), {[Dy[Mo (CN) ](HL )(H O) (CH OH)] ⋅ H O} (3), and {[Dy[Mo (CN) ](HL ) (H O) ]} ⋅ 2H O⋅CH OH (4) were obtained.

Synergy of Magnetic Anisotropy and Ferromagnetic Interaction Triggering a Dimeric Cr(II) Zero-Field Single-Molecule Magnet.

A novel Cr-dimeric complex, [CrN(SiPr)(μ-Cl)(THF)] (), has been successfully constructed using a bulky silyl-amide ligand. Single-crystal structure analysis reveals that complex exhibits a binuclear motif, with a CrCl rhombus core, where two equivalent tetra-coordinate Cr centers in the centrosymmetric unit display quasi-square planar geometry. The crystal structure has been well simulated and explored by density functional theory calculations.

Understanding the Magnetic Relaxation Mechanism in Mixed-Valence Dilanthanide Complexes with Metal-Metal Bonding: A Theoretical Investigation.

Theoretical investigations on mixed-valence dilanthanide complexes (Cp)LnI (Ln = Tb, Dy, and Ho) indicate that the total spin of the 4f shell couples preferentially to the σ electron spin and then to the orbital angular momentum, improving the strength of spin-orbit coupling (SOC) for each magnetic center. On the other hand, the concentration of negative charges containing the delocalized σ electron in the axial direction leads to a large crystal-field (CF) splitting. Both strong SOC and large CF splitting lead to the largest energy barrier of such complexes up to now.

Ligand Modulation of the Structures and Magnetic Relaxation in Triangular Dy Complexes Based on a Tricompartmental Scaffold.

Using a novel tricompartmental hydrazone ligand, a set of trinuclear Dy complexes has been isolated and structurally characterized. Complexes Dy  ⋅ Cl, Dy  ⋅ Br, and Dy  ⋅ ClO feature a similar overall topology but different anions (Cl , Br , or ClO ) in combination with exogenous OH and solvent co-ligands, which is found to translate into very different magnetic properties. Complex Dy  ⋅ Cl shows a double relaxation process with fast quantum tunneling of the magnetization, probably related to the structural disorder of μ -OH and μ -Cl co-ligands.

A synergistic therapeutic nano-eyedrop for dry eye disease based on ascorbic acid-coupled exosomes.

Dry eye disease (DED), a complex ocular surface disease with a high prevalence rate, is associated with corneal injury, excess oxidative stress and inflammation. Current therapeutic strategies, including artificial tears and anti-inflammatory agents, are unable to address all the deleterious factors or to achieve a clinical cure due to their temporary or side effects. Here, we prepared a multiple-functional eyedrop based on the deposition of gold nanoparticles (AuNPs) reduced by ascorbic acid (AA) onto the exosomal phospholipid membrane of mesenchymal stem cell (mExo)-derived exosomes (mExo@AA).

Five-Coordinated Dysprosium Single-Molecule Magnet Functionalized by the SMe Group.

A five-coordinate mononuclear Dy(III) complex with a geometry (square-pyramid), [Dy(X)(DBP)(TMG(H))] [X = 3-(methylthio)-1-propoxide, DBP = 2,6-di--butylphenoxide, and TMG(H) = 1,1,3,3-tetramethylguanidine] (), was designed and synthesized. The complex displays a large anisotropy barrier of 432 cm in the absence of a dc magnetic field benefiting from the strong interaction between the phenolate and Dy(III) ion. calculations reveal that the most possible relaxation pathway is going through the second excited state.

X-Ray Triggered Coordination-Bond Breakage in Dysprosium-Organic Framework and its Impact on Magnetic Properties.

Photosensitive lanthanide-based single-molecule magnets (Ln-SMM) are very attractive for their potential applications in information storage, switching, and sensors. However, the light-driven structural transformation in Ln-SMMs hardly changes the coordination number of the lanthanide ion. Herein, for the first time it is reported that X-ray (λ=0.