A synthesis of six novel copper(II) compounds with a dinuclear molecule [Cu2(Ln)2], n 1/4 1-6 is presented with their structures determined. The initial ligand molecules H2Ln are of bis(phenol)amine type having the third amine arm composed by-CH2THF (1-4) or-CH2CH2OMe (5, 6) moieties, respectively. Their phenyl rings differ by the attached groups (t-Bu/MeO 1, t-Bu/Me 2, Me/Me 3, Cl/Cl 4, t-Bu/Me 5, Me/Me 6) at orto/para positions. The XRD structural analysis demonstrates the surroundings of Cu(II) centers by three phenolates' oxygen atoms, one tetrahydrofuranyl/methoxyethyl oxygen atom (axial), and one amine nitrogen atom, showing distorted square-pyramidal CuO3NO chromophores. One of the phenolates' oxygen atoms of each Ln connects the adjacent Cu(II) centers within the dinuclear [Cu2L2] molecules. These form two short Cu-O-Cu bridges enabling a medium to strong antiferromagnetic (AFM) coupling (2J: from-32 cm-1 (2) to-552 cm-1 (4)). The observed interaction's magnitude is compared with their respective Cu-O(pH)-Cu angle and Cu Cu distance. Its differentiation may be related to the phenyl rings' attached groups. Bulky t-Bu on the phenyl ring's orto position is in all cases related with a shorter Cu Cu distance, smaller AFM coupling and larger distortion of the coordination sphere's basal plane.

One-dimensional (1D) coordination polymers offer rich chemical tunability and magnetic and semiconducting properties, making them promising for advanced magnetic, optoelectronic, and catalytic applications. Coordination polymers constructed from paramagnetic metal ions and diverse linkers can display both magnetic and semiconducting properties, while their potential to dissociate into smaller metal-ligand fragments enables the formation of catalytically active species. In this work, we synthesized two manganese(II)-azido coordination polymers 1 and 2 by reacting Mn(ClO4)2·6H2O with tridentate NNS donor ligands in the presence of sodium azide. X-ray diffraction (XRD) analysis confirmed a 1D polymeric chain topology featuring alternating double end-on (EO) and double end-to-end (EE) azido bridges. Notably, compound 2 features the smallest EO-bridging angles and the shortest EO-azide-bridged Mn···Mn separations reported to date among Mn(II)-azide chains adopting this specific bridging motif. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and DLS analyses revealed a more ordered nanostructure in 2. Magnetic studies revealed distinct behaviors, with 1 exhibiting overall antiferromagnetic interactions, while 2 displayed a ferromagnetic exchange. Charge transport measurements reveal a slightly enhanced hole mobility for 2, attributed to its structural ordering. Furthermore, both the polymers also demonstrate efficient catalytic activity in hydrosilylation of biomass-derived carbonyl compounds, depolymerization leads to the active Mn-species, and the path involves Mn-hydride intermediate.

Five defective dicubane Ni2Dy2 complexes with the general formula [Ni2Dy2(L)4X2(solvent)n], where (X = NO3- (1), acetylacetonate (2), NCS- (3), OAc- (4), and pivalate (5)), were synthesized and structurally characterized to investigate how co-ligand variation influences magnetic exchange interactions, anisotropy, and relaxation dynamics. Single-crystal X-ray diffraction reveals that the DyIII ions adopt highly axial coordination environments ranging from distorted square-antiprismatic and triangular dodecahedral geometries in complexes 1-4 to a near pentagonal-bipyramidal geometry in 5. All complexes exhibit zero-field single-molecule magnet behavior, consistent with strong axial ligand fields. CASSCF calculations confirm that the shortest Dy-O(phenoxide) bonds govern the orientation of the magnetic easy axes, aligning toward terminal phenoxide donors. Broken-symmetry DFT calculations indicate uniformly positive Dy-Ni coupling constants, in line with typical ferromagnetic 3d-4f interactions, while the Ni-Ni coupling strength and sign are dictated by the Ni-O-Ni bridging angle, with a crossover between ferro- and antiferromagnetic regimes near 99°. This structural sensitivity rationalizes the comparatively weaker relaxation dynamics observed in complex 3, which features a larger Ni-O-Ni bridging angle accompanied by antiferromagnetic Ni-Ni interactions. These combined experimental and theoretical results establish robust structure-property correlations that provide a rational strategy for tuning anisotropy and exchange topology in Ni-Ln butterfly clusters to advance 3d-4f single-molecule magnet design.

Mn-oxo clusters,as molecular magnetic materials,were promising candidates for magnetic materials due to their different oxidation states with variable numbers of unpaired electrons and variable geometric arrangements[1].The magneto-structural correlations and the solvent effect on properties in such clusters remain an inchoate area that de-serves to be explored in detail.

Abstract Three isostructural dinuclear lanthanide complexes, [Ln2(μ-HL)2(HL)2(NO3)2]·4MeCN (Ln = DyIII (1), ErIII (2), YbIII (3)), were synthesized under base-free conditions using the o-vanillin- and 2-aminophenol-based Schiff base H2L. This ligand exhibits two distinct protonation-dependent coordination modes that have not been previously shown in this class of ligands. The simultaneous presence of monoanionic HL and monoanionic zwitterionic HL coordination leads to an unusual combination of chelating and asymmetric bridging features, generating a flexible and moderately axial LnO7N environment. All three complexes display field-induced single-molecule magnet behavior, and complex 1 additionally shows measurable zero-field slow relaxation. Detailed ac susceptibility studies indicate that their relaxation dynamics are dominated by Raman processes, with additional Orbach relaxation in 2 and a direct process in 3. We further combine dc and ac magnetic data with ab initio calculations, providing insight into the relaxation dynamics and the contributions of single-ion anisotropy and weak exchange interactions, if any. The combined structural, magnetic, and theoretical analyses demonstrate that base-free synthesis allows controlled ligand protonation, which in turn modulates crystal field effects and governs the magnetic relaxation pathways in these dinuclear lanthanide systems.

Copper(II) compounds exhibit interesting magnetic properties due to halide–halide, copper–halide, and intermolecular hydrogen bond interactions. In this study, seven new copper(II) bromide complexes were synthesised, six of which contain Dabco (1,4-diazabicyclo[2.2.2]octane) as a ligand. Single-crystal X-ray diffraction data were refined using both conventional spherical-atom models and a non-spherical-atom approach implemented in NoSpherA2. Magnetic properties were investigated by temperature-dependent magnetic susceptibility and field-dependent magnetisation measurements, analysed using a molecular field approximation. Crystallographic analysis shows that NoSpherA2 significantly improves the description of hydrogen atom positions, yielding C–H and N–H bond lengths closer to neutron diffraction values than conventional refinement. Magnetic measurements indicate that interactions between mononuclear copper(II) centres are determined primarily by the nature of intermolecular exchange pathways rather than copper–copper separations alone. Despite comparable Cu···Cu distances, complexes lacking N–H···Br hydrogen bonds exhibit only weak antiferromagnetic interactions, whereas stronger coupling, effective up to 150 K, is observed when such hydrogen bonds connect neighbouring complexes. These results highlight the importance of hydrogen-bond topology and three-dimensional connectivity in governing magnetic behaviour in mononuclear copper(II) systems.

Precious dental alloys based on gold, platinum, palladium or silver exhibit excellent corrosion resistance, high biocompatibility and optimal mechanical properties for use in prosthetic dentistry. In comparison, base dental alloys based on chromium, cobalt or nickel are cheaper, have excellent mechanical properties but poorer corrosion resistance and biocompatibility. This research examined the magnetic properties of dental alloys in a magnetic field, which vary with composition and electronic structure. Materials can be classified as diamagnetic, paramagnetic or ferromagnetic, depending on how they respond to an external magnetic field, with noble metals usually showing weak or negligible magnetic behaviour. Experimental results of magnetic force measurements in precious dental alloys have shown that most exhibit diamagnetic properties, being weakly repelled by a magnetic field, and do not retain any magnetization when the magnetic field is removed. One of the tested precious-metal alloys exhibited paramagnetic behaviour, indicating a weak attraction in a magnetic field. In contrast, all studied dental base-metal alloys exhibited stronger paramagnetic interactions with magnetic fields. Diamagnetic properties of precious-metal dental alloys present a significant advantage in the medical environment, especially in magnetic resonance imaging (MRI) as diamagnetic materials do not interfere with magnetic fields and thus reduce image distortion and patient risk during MRI. However, paramagnetic base-metal dental alloys can cause local heating or imaging artefacts under MRI conditions. Therefore, precious-metal dental alloys are more suitable for patients who may require MRI, as they combine functional durability with greater safety in medical diagnostics.

The excellent magnetic properties of metal clusters lay a theoretical research foundation for their applications in high-density information storage, magnetic refrigeration, quantum computing, and other related fields. Nonetheless, the deliberate synthesis of novel and structurally robust polynuclear metal assemblies remains a challenging task. This report details the synthesis, structural and magnetic characterization of a heptanuclear nickel cluster, [Ni7(FOS)4(DMP)2(bdp)4(H2O)6]& centerdot;2ClO4 (Ni7) (H2FOS: dihydroxy((2R,3S)-3-methyloxiran-2-yl)phosphine oxide, DMP: 3,5-Dimethylpyrazole, bdp: 1,2-bis(3,5-dimethyl-1H-pyrazol-1-yl)-2-((1-phenylethyl)amino)ethan-1-olate), using the ligand 1,2-bis(3,5-dimethyl-1H-pyrazol-1-yl)ethane-1,2-diol (H2bdped). During the reaction, phenethylamine from the fosfomycin-phenethylamine salt reacted in situ with the H2bdped ligand to generate a new bdp- ligand, which coordinated to nickel metal centers and stabilized the cluster. X-ray single-crystal diffraction proves that the crystal structure is a symmetric arrangement composed of two Ni3 units and a central Ni atom. Meanwhile, mass spectrometry (MS) indicated heterolytic cleavage of the cluster, further supporting a structure composed of one Ni3 unit and one Ni4 unit. Variable-temperature and variable-field magnetization data revealed that the Ni7 cluster exhibits a distinct ferromagnetic ground state at temperatures below 2 K. This property suggests potential use in high-frequency electromagnetic components, such as magnetic cores, magnetic rods, permanent magnets, and memory storage elements, indicating broad application prospects.

The bridging nature of in situ solvent-generated hydroxido (HO-) and methoxido (MeO-) groups has been utilized to obtain tetranuclear open-cubane and stepped-cubane [Cu4] complexes: [Cu4(L)2(H2O)2(μ3-OH)2](ClO4)4·3H2O (1) and [Cu4(L)2(μ-NO3)2(μ3-OMe)2](NO3)2·H2O (2) (HL = 2,6-bis-{(semicarbazidoimino)}-4-methylphenol). The ligand HL, possessing two metal ion-capturing bay regions, immediately seizes two copper(II) ions in solution to form Cu2L species, with their remaining coordination sites loosely occupied by H2O or NO3- groups, ultimately leading to the formation of complexes 1 and 2. The treatment of HL with Cu(ClO4)2·6H2O and Cu(NO3)2·3H2O metal ion salts is responsible for the in situ generation of the supporting HO- and MeO- linkers to sustain two different topologies from the same MeOH-H2O reaction medium. In 2, the bridging coordination of the nitrate anion to two copper(II) centers guides the approach of individual Cu2L units for Cu4 cluster formation, whereas for 1, the approach of the Cu2L units is different due to the coordination of labile H2O molecules to the copper(II) centers. These complexes have been characterized by X-ray crystallography, and their magnetic properties have been studied. Both the complexes exhibit interesting catalytic oxidation behavior for mimicking the enzyme behaviours of catecholase oxidase and phenoxazinone synthase, using model substrate 3,5-DTBCH2 and AP with the Kcat values 12.08, 1.845 and 0.101, 1.522 h-1, respectively. In vitro ct-DNA interaction studies of complexes 1 and 2 revealed electrostatic binding in the groove region of DNA. Variable-temperature magnetic studies provided a J value of approximately -180 cm-1 for 1 and -190 cm-1 for 2, which were supported by DFT-based calculations with various functionals (PBE0, B3LYP, CAM-B3LYP, and ωr2SCAN).

A series of heterometallic octanuclear Ni4Ln4 complexes (Ln = Dy for 1, 3, and 4; Tb for 2) has been synthesized using closely related multinucleating Schiff-base ligands in combination with nitrobenzoate co-ligands. Single-crystal X-ray diffraction reveals that these ligands direct the assembly of an unusual Ni4Ln4 topology composed of two linked {Ni2Ln2O4} cubane subunits, in contrast to earlier studies on analogous ligand systems that predominantly yielded dinuclear, linear trinuclear, arch-like, or defective dicubane-like tetranuclear cores. Static magnetic susceptibility measurements indicate weak magnetic exchange interactions, with an overall ferromagnetic contribution emerging at low temperatures. The dynamic magnetic behavior is governed by the anisotropic Dy(III)/Tb(III) centres; however, the non-collinear orientation of lanthanide anisotropy axes results in partial cancellation of magnetic anisotropy, leading to SMM-like behavior with fast magnetic relaxation dominated by quantum tunneling effects. These results highlight the role of anisotropy alignment and ligand design in controlling magnetic relaxation in 3d-4f clusters.

A new hydrazone-based Schiff base ligand, (E)-N'-(2-hydroxy-3-methoxy-5-methylbenzylidene)nicotinohydrazide (H2L), has been employed for the synthesis of a family of four dinuclear Dy(III) complexes, [Dy2(L)2(OAc)2(H2O)2]·H2O (1), [Dy2(L)(dbm)2(CH3OH)2]·2CH2Cl2 (2), [Dy2(L)(pnba)2(H2O)0.8(CH3OH)1.2]·2H2O·2.8CH3OH (3), and [Dy2(L)2(mnba)2(H2O)2(CH3OH)2]·2CH3OH (4), obtained through systematic variation of ancillary anionic co-ligands. Single-crystal X-ray diffraction reveals that all complexes feature a closely related diphenoxide-bridged {Dy2(L)2} core, while the Dy(III) centers adopt distorted eight- or nine-coordinate geometries depending on the co-ligand environment. Direct-current magnetic measurements show that complexes 1 and 2 display an overall antiferromagnetic (AFM) signature at low temperatures, whereas complexes 3 and 4 exhibit dominant ferromagnetic (FM) coupling. Ab initio calculations reveal that the intramolecular Dy-Dy interaction involves an interplay between a FM dipolar coupling and AFM exchange. In complexes 1 and 2, the AFM interaction dominates the bulk magnetic response while complexes 3 and 4 exhibit a FM curve profile. This interplay has a decisive impact on the single-molecule magnet (SMM) properties. As a consequence, complexes 1 and 2 exhibit only weak, field-induced slow magnetic relaxation due to enhanced quantum tunneling of magnetization, whereas complexes 3 and 4 display clear zero-field SMM behavior with superior relaxation performance. Theoretical analysis further demonstrates that co-ligand-dependent coordination geometries control the orientation of the magnetic easy axes and modulate the effectiveness of magnetic coupling, thereby establishing a direct correlation between the overall magnetic interaction and the observed SMM behavior in this dinuclear Dy(III) family.

Magneto-structural and theoretical investigations revealing how co-ligand variation modulates magnetic exchange interactions, anisotropy and relaxation dynamics in a series of Ni 2 Dy 2 butterfly complexes, all exhibiting zero-field SMM behavior.

A novel phenol-alcohol-pyridine (OON) donor-bearing ligand (HL1) has been identified while exploring the coordination reactivity of an orthodox Schiff base HL (ON donors only) with a dangling pyridine group via the hydration of the imine function (-HCN-) embedded within HL. The µ3 bridging mode of the hemiaminal alkoxido O donor of [L1]2- induces the self-aggregation of four [Cu(L1)] units into a novel tetranuclear [Cu(L1)]4 (3) complex through cyclization of the four [Cu(L1)] units. The ligand transformation (HL → HL1) in copper(II) bound forms was justified by a DFT study. Control reactions of HL with ZnCl2·H2O and N-donor co-ligands showed the stability and coordination of the original L- form in [Zn(L)(ampy)Cl] (1) and its imine-hydrolyzed form in [Zn(dial)(bpy)Cl] (2). Complex 3 shows weak antiferromagnetic intermolecular interactions below 100 K. Electrochemical studies demonstrated the efficacy of complex 3 towards the OER. Complex 1 exhibited reasonable antibacterial, antibiofilm and antivirulence activity, demonstrating its potential as a therapeutic alternative, in sharp contrast to complex 3.

The ligand gave two types of Cu 4 assemblies showing new molecular structural patterns, interacting magnetic properties, DNA binding property and catalytic activity.

Three N,N'-dimethylethylenediamine derivatives of substituted bis(phenol)diamine ligands (L1-3) have been found in either of three iron(III) 8-quinolinato (L4) coordination compounds [FeL1-3L4]center dot(solvent) (1-3). Herein, H2L1 stands for 2,4-dimethylphenol, H2L2 for 2,4-dichlorophenol, while H2L3 for 2-(tert-butyl)-4-methoxyphenol derivative, respectively. HL4 is 5-chloro-7-iodo-8-hydroxyquinoline being present in each of 1-3. X-ray structure analysis reveals mononuclear octahedral FeIIIO3N3 chromophores with tetradentate O,O,N,N L1-3 and bidentate O,N L4. All three title compounds show paramagnetic behavior, which is consistent with the monomeric character of their metal centers. Compounds 2 and 3 reveal high spin (S = 5/2) in a whole 2-300 K range, while 1 shows the high spin character only above 200 K. By lowering the temperature, its magnetic susceptibility gradually decreases due to spin crossover towards low spin (S = 1/2). The halogen-pi(aromatic ring) structural interactions for 1 differ to 2 and 3 and may be related to such different magnetic behavior. Room temperature electronic absorption spectra of all three compounds 1-3 feature LMCT bands associated with phenolate(pi)-> Fe (III)(d pi*) charge transfer in the 450-700 nm region. These bands are in accordance with the DFT calculations for the high spin species only.

ABSTRACT Spin crossover (SCO) materials capable of exhibiting wide thermal hysteresis loops near room temperature are highly desirable for molecular switches, memory devices, and sensors. While such behavior has been extensively studied in Fe(II), Fe(III), and Co(II) complexes, examples in Mn(III)‐based systems remain limited due to the typically favored high‐spin state and subtle structural changes accompanying spin‐state switching. Herein, we report a Mn(III)‐based spin‐crossover complex [Mn(3‐MeO‐5‐Me‐sal 2 ‐323)]·BF 4 ( 1 ), which exhibits a record‐breaking asymmetric thermal hysteresis width exceeding 100 K, spanning room temperature. Detailed magnetic, calorimetric, and crystallographic studies reveal that this exceptional cooperativity is driven by an unprecedented two‐dimensional (2D) hydrogen‐bonding network formed between the complex cations and ordered BF 4 – counterions. High‐resolution transmission electron microscopy (HRTEM) reveals locally ordered nanoscale domains, confirming retention of the supramolecular stacking motif at the nanoscale, consistent with the interplanar spacings obtained from single‐crystal x‐ray analysis. Variable‐temperature Raman spectroscopy further corroborates Mn(III) spin crossover via spin‐state‐dependent metal–ligand vibrational signatures. Overall, the present report demonstrates the critical role of dimensionality in supramolecular hydrogen‐bonding cooperativity in governing bistability in Mn(III)‐SCO systems, offering a powerful design strategy for developing next‐generation switchable materials.

The Ga-rich region of the Fe-Ni-Ga ternary system was investigated, by exploring a line of compositions FexNi3-xGa4, with 0.5 ≤ x ≤ 2.5. The single-phase cubic material was found only at the composition Fe1.5Ni1.5Ga4 and its immediate vicinity, representing a new phase in the Fe-Ni-Ga diagram. The homogeneity range of this phase was estimated by additionally exploring a set of compositions FexNiyGaz around the central composition Fe1.5Ni1.5Ga4. The structural model was constructed based on the structure of the binary Ni3Ga4 parent phase, which crystallizes in the cubic Ia3̅d space group. We have considered that by substituting Fe for Ni, the Ia3̅d structure is preserved, with the Fe and Ni being statistically distributed at their 48g Wyckoff site. The possibility of a symmetry-reduced chiral structural model I4132 driven by chemical ordering of Fe and Ni cannot be entirely ruled out on the basis of the crystallographic study. The magnetic study of the Fe1.5Ni1.5Ga4 phase has revealed that the material forms a spin glass phase below the spin freezing temperature Tf ≈ 9 K. Since the spin glass ordering of the Fe and Ni magnetic moments is compatible with their random distribution, the magnetic study supports the disordered cubic Ia3̅d model.

A novel N,N'-dimethylethylenediamine derivative of substituted bis(phenol)diamine ligands, namely 2-(tert-butyl)-4-methylphenol in H2L1, was synthesized by a convenient green procedure. Nickel)II) complex [NiL1] 1 has been synthesized and characterized by various methods along with crystal structure determined. Ni(II) coordination center in a mononuclear complex is surrounded by two phenolate oxygen atoms and two amine nitrogen atoms of the ligand in a square planar arrangement. The magnetic susceptibility of the title complex indicates a paramagnetic behavior above 150 K, while strong ferromagnetism below 100 K. Furthermore, the cyclic voltammetry studies show two ligand-centered oxidation of the phenolate groups to phenoxyl radical and the metal-centered reduction of Ni(II) to Ni(0). The Glaser coupling reaction of phenylacetylene was also studied. A strong catalytic activity at room T in THF solvent is observed for 1 in the presence of zinc powder as a reducing agent. A full conversion rate was achieved after 7 h at 25 degrees C. The DFT analysis corroborates with the square-planar NiO2N2 chromophore of 1 being reduced in catalytically active Ni(0) by applied Zn. The calculated Gibbs free energy of the reaction leading to the formation of the substrate Ni-complex is favorable endothermic. Most of the data for 1 were obtained also for the very similar previously reported [NiL2] 2, with 2,4- di tert-butylphenol in H2L2, which were than compared.

Aliovalent doping of the two-dimensional dimer antiferromagnet SrCu_2(BO_3)_2 has long been proposed as a potential route toward realizing resonating valence bond (RVB) superconductivity in this system; however, experimental progress has remained limited. This study explores the effects of La doping on the ground state of SrCu_2(BO_3)_2 and reports the first flux growth of Sr_1-xLa_xCu_2(BO_3)_2 single crystals with nominal doping levels up to x = 0.15. Powder X-ray diffraction and energy-dispersive X-ray spectroscopy confirm the successful incorporation of La on the Sr sites within the tetragonal I4̅2m structure, although the effective doping was limited to approximately 50