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Comprehensive Summary: The precise syntheses of transition–rare‐earth metal clusters with desired structures remain a great challenge. Herein, by utilizing SO42– anion released by in‐situ decomposition of sodium dodecyl sulfate (SDS) as a template, a series of novel high‐nuclearity 3d‐4f clusters, formulated as [Ni24Pr22(μ3‐OH)31(pida)24(SO4)4(NO3)9(CH3COO)3]·Br4·(NO3)11·16H2O·25CH3OH (1, H2pida = N‐phenyliminodiacetic acid), [Ni24Nd22(μ3‐OH)31(pida)24(SO4)4(NO3)9(CH3COO)3]·Br4·(NO3)11·14H2O·24CH3OH (2) and [Ni24Gd22(μ3‐OH)36(bida)24(SO4)7(NO3)3(CH3COO)3]·(SO4)·Br4·(NO3)4·31H2O·32CH3OH (3, H2bida = N‐benzyliminodiacetic acid), have been successfully isolated. X‐ray crystal structure analyses reveal that all the cationic {Ni24RE22} cores in 1—3 possess a ball‐like structure with C3v symmetry, and can be viewed as consisting of an inner {RE22} core and an outer {Ni24} shell. From 1 and 2 to 3, due to the lanthanide contraction effect, the coordination numbers for rare‐earth metal centers in {RE22} are different, resulting in different number of SO42– and NO3– anions to support and stabilize the skeleton structures. Meanwhile, the magnetic properties of complexes 1—3 were also studied. The result revealed that complexes 1—3 show antiferromagnetic/ferrimagnetic interactions, and 3 exhibits magneto‐caloric effect at ultralow temperatures with a maximum –ΔSm (magnetic entropy change) value of 33.03 J·kg−1·K−1 at 3.0 K and 7 T. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The precise syntheses of transition–rare‐earth metal clusters with desired structures remain a great challenge. Herein, by utilizing SO42– anion released by in‐situ decomposition of sodium dodecyl sulfate (SDS) as a template, a series of novel high‐nuclearity 3d‐4f clusters, formulated as [Ni24Pr22(μ3‐OH)31(pida)24(SO4)4(NO3)9(CH3COO)3]·Br4·(NO3)11·16H2O·25CH3OH (1, H2pida = N‐phenyliminodiacetic acid), [Ni24Nd22(μ3‐OH)31(pida)24(SO4)4(NO3)9(CH3COO)3]·Br4·(NO3)11·14H2O·24CH3OH (2) and [Ni24Gd22(μ3‐OH)36(bida)24(SO4)7(NO3)3(CH3COO)3]·(SO4)·Br4·(NO3)4·31H2O·32CH3OH (3, H2bida = N‐benzyliminodiacetic acid), have been successfully isolated. X‐ray crystal structure analyses reveal that all the cationic {Ni24RE22} cores in 1—3 possess a ball‐like structure with C3v symmetry, and can be viewed as consisting of an inner {RE22} core and an outer {Ni24} shell. From 1 and 2 to 3, due to the lanthanide contraction effect, the coordination numbers for rare‐earth metal centers in {RE22} are different, resulting in different number of SO42– and NO3– anions to support and stabilize the skeleton structures. Meanwhile, the magnetic properties of complexes 1—3 were also studied. The result revealed that complexes 1—3 show antiferromagnetic/ferrimagnetic interactions, and 3 exhibits magneto‐caloric effect at ultralow temperatures with a maximum –ΔSm (magnetic entropy change) value of 33.03 J·kg−1·K−1 at 3.0 K and 7 T. [ABSTRACT FROM AUTHOR]

The capability of bis(dioxolene) ligands to access multiple redox states makes them ideal candidates to tune the electronic properties of metal complexes, for example to achieve valence tautomerism (VT). In this study, a family of dinuclear cobalt complexes have been isolated with the bridging bis(dioxolene) thean− ligand in the cat2−‐cat2−, cat2−‐SQ⋅− and SQ⋅−‐SQ⋅− states (cat2−=catecholate, SQ⋅−=semiquinonate): [{CoIII(tpa)}2(theacat−cat)](PF6)2 (1), [{CoIII(tpa)}2(theacat−SQ)](PF6)3 (2), and [{CoIII(tpa)}2(theaSQ−SQ)](PF6)4 (3) (theaH4=2,3,6,7‐tetrahydroxy‐9,10‐dimethyl‐9,10‐dihydro‐9,10‐ethanoanthracene, tpa=tris(2‐pyridylmethyl)amine). Multi‐technique analysis confirms that 1, 2 and 3 adopt low spin‐CoIII containing {CoIII‐cat‐cat‐CoIII}, {CoIII‐cat‐SQ‐CoIII} and {CoIII‐SQ‐SQ‐CoIII} states, respectively. Compound 1 undergoes thermally‐induced {CoIII‐cat‐cat‐CoIII} ⇌ {CoIII‐cat‐SQ‐CoII} VT in the solid‐ and solution‐states above 300 K, involving high spin‐CoII. This interconversion is contrary to expectations, as tpa typically stabilizes low spin‐CoIII‐catecholate. Compound 2 is mixed‐valence class II/II–III, indicating a localized electronic structure, with electron transfer faster than the EPR and solvent rearrangement timescales, but slower than the infrared timescale. Compound 3 exhibits strong antiferromagnetic exchange. The overlap between the dioxolene π‐orbitals in thean− increases the accessibility of the cat2−‐SQ⋅− state, resulting in VT for 1. This study demonstrates that thean− can be isolated in multiple oxidation states in metal complexes, which is promising for applications in magnetic materials. [ABSTRACT FROM AUTHOR]

Abstract As a 1.8 nm ZnSe nanocrystal is progressively doped with 1%, 5%, and 10% Fe, it shows a progressive change in its magnetic properties from a superparamagnetic FM‐dominated exchange type to an onset of AFM exchange with evidence of spin frustration. Magnetization measurements allow to obtain exchange coupling constants that are compared to the results of a Broken‐Symmetry Density Functional Theory (BS‐DFT) model of a doped (ZnSe)34 cluster. DFT shows a capability to reproduce the experimental pattern of the increasing influence of AFM exchange as doping concentration increases. The material phase segregates at the edges where strained rhombic surface sites are the preferred doping sites of iron. Large concentrations of iron leads to the formation of Fe clusters and complex exchange patterns that result in spin frustration in some iron trimers but none in the others. The spin frustration of these complex systems by assuming mirror symmetry of the sites when fitting by using BS‐DFT formalism is classified and analyzed. While some individual J constants obtained have significant errors, the averaged exchange constants are generally in good agreement with our experimental data.

A family of polyoxo(alkoxo)lanthanide cluster {Ln15} (Ln = Eu (1), Gd (2), Tb (3)) was successfully isolated via a simple hydrolysis reaction of lanthanide metal ions in the presence of tricine ligands. X-ray diffraction analyses revealed that {Ln15} displayed a wheel-like structure with a µ5-chloride anion as a template. Interestingly, each analog showed distinctive functions based on the different Ln(III) ions. Complexes 1 and 3 in the solid state emitted the characteristic fluorescence of Eu(III) or Tb(III). The fluorescence lifetimes of the 5D0 excited state for 1 and the 5D4 excited state for 3 were tested, and the values were 890 and 250 μs, respectively. Meanwhile, gadolinium analog 2 exhibited a magneto-caloric effect at ultralow temperatures with a maximum −ΔSm value of 29.9 J·kg−1·K−1 at 3 K and 7 T.

[Display omitted] • A simple method of high temperature ignition to metalorganics was successfully used to synthesize composites of NiCo 2 O 4 , NiO, and Co 3 O 4. • Through the introduction of a magnetic field tuning method during the fabrication process, NiCo 2 O 4 , NiO, and Co 3 O 4 nanoparticles are arranged closely in epoxy resin. This modification enhances the magnetic exchange interactions within the material, thereby improving both dielectric loss and magnetic loss characteristics. As a result, the minimum reflection loss RL values is up to −45.11 dB with an effective bandwidth of 4 GHz. • This paper presents a straightforward method to heighten the microwave absorption performance of NiCo 2 O 4 by modifying the macroscopic order and degree. A simple method of high-temperature ignition to metalorganics was successfully used to synthesise composites of NiCo 2 O 4 , NiO and Co 3 O 4. A detailed investigation of the composite's microwave absorption properties revealed the magneto-alignment effect. By closely arranging NiCo 2 O 4 , NiO and Co 3 O 4 nano-particles in epoxy resin, the magnetic exchange is strengthened under the influence of a magnetic field. The sample without magnetic alignment, S 0 , exhibited poor absorption efficiency with reflection loss (RL) values hardly reaching − 10 dB across a frequency range of fixed and different thicknesses (2–18 GHz). In comparison, the oriented composite exhibited higher permittivity and permeability, particularly in the high-frequency range. Considering the improved impedance matching and reasonable adjustment of dielectric and magnetic losses, the microwave absorbing performance of the oriented composite substantially improved in the 10–14 GHz range. The minimum RL is reduced to − 45.11 dB with an effective bandwidth of 4 GHz. Herein, we present a straightforward method to increase the microwave absorption performance of NiCo 2 O 4 by modifying the macroscopic order and degree. [ABSTRACT FROM AUTHOR]

The consequences of non‐uniform exchange in magnetic systems are reported. The quantum mechanical exchange interaction between spins is responsible for the phenomenon of magnetic order, and is generally considered to be uniform across bulk magnetic systems. Partly inspired by the Dzyaloshinskii‐Moriya interaction—also known as antisymmetric exchange—a linearly varying exchange interaction is used along a magnetic strip as a route to spatial inversion symmetry‐breaking. It is found that, in addition to asymmetric modes and localization, spatially varying exchange can be used to design nonreciprocal magnetic signal excitation at frequencies that are tunable. Moreover, the authors' work predicts nonreciprocity to occur across a vast range of frequencies up to hundreds of GHz. Such spin wave engineering is a key area of ongoing research in the fields of magnonics and spintronics, which are expected to enable the next generation of wireless communication technology and information processing. Analogous nonreciprocity is expected to occur in other wave systems with gradient properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthetic methods to prepare 3d-metal complexes with o-iminoquinones. • The structural features of metal complexes with functionalized o-iminoquinones. • Influence of the organic ligands structure on the magnetic properties of complexes. The present review covers the coordination compounds of the "late" transition metals of the 3d row (Mn, Fe, Co, Ni, Cu) based on sterically hindered functionalized o-iminobenzoquinone type ligands featured by the presence of various functional groups. These functions cause the changes of the molecular and electronic structures of metal complexes and the degree of steric shielding of the metal centre. The latter parameter affects the mutual arrangement of interacting magnetic orbitals and introduces specific changes to the channels of magnetic exchange interactions in the coordination compound. The following aspects are discussed in detail in the present review: the relationship between the structural modifications and the magnetic behaviour of o-iminobenzoquinonato complexes of 3d row elements; the effect of the molecular structure transformations both on the oxidation state and the spin state multiplicity of the metal centre, as well as on the oxidation state of the redox-active organic ligand. The systematization of the literature published mainly from 2007 to 2020 has been carried out. The bibliography contains 173 references. [ABSTRACT FROM AUTHOR]

Nanocomposite (x)NiO/(1-x)CdFe 2 O 4 were synthesized using co-precipitation method with x = 0, 0.1, 0.2, 0.3, 0.4, 0.5 and 1. The X-ray diffraction patterns reveal the presence of NiO and CdFe 2 O 4 phases with no chemical reaction between both phases. The scanning electron microscope images show the agglomeration between the particles, revealing the magnetic interaction between NiO and CdFe 2 O 4 nanoparticles. The band-gap energy E g , measured from UV–vis spectra, decreases with the increase of the particle size measured from the transmission electron microscope. The obtained data from the vibrating sample magnetometer indicate that NiO and CdFe 2 O 4 nanoparticles are interacting magneto-statically. The coercivity and the saturation magnetization values of the nanocomposites are found to be in the ranges 3.22–378.62 G and 0.27–2.34 emu/g respectively. Exchange couple interaction between NiO and CdFe 2 O 4 is confirmed from the single peak observed in switching field distribution curves. • The spinel cubic structure of CdFe2O4 nanoparticles and the fcc structure of NiO nanoparticles are confirmed by XRD. • TEM shows agglomeration of nanoparticles due to strong magnetic interaction between NiO and CdFe2O4. • The variation of the band gap energy with the particle size referred to the quantum confinement effect. • The switching field distribution curves indicate the exchange coupling interaction due to the observed single peak. [ABSTRACT FROM AUTHOR]