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A high-nuclearity {Ni18} complex (1) with a unique 'flying saucer' motif has been prepared from the organic chelate, α-methyl-2-pyridine-methanol (mpmH), in conjunction with bridging azido (N3 -) and peroxido (O2 2-) ligands. Magnetic susceptibility measurements revealed the presence of both ferro- and antiferromagnetic exchange interactions between the metal centres in 1, and the stabilization of spin states with appreciable S values at two different temperature regimes. The end-on bridging azido and alkoxido groups are in all likelihood the ferromagnetic mediators, while the η3:η3:μ6-bridging peroxides most likely promote the antiparallel alignment of the metals' spin vectors, yielding an overall non-zero spin ground state for the centrosymmetric compound 1. Furthermore, the {Ni18} nanosized cluster behaves as a single-molecule magnet, exhibiting magnetic hysteresis at low temperatures and two relaxation processes at 15 K and 1.3 K, a very rare phenomenon in polynuclear magnetic 3d-metal clusters.

The employment of the [1+1] condensation approach for the preparation of new macrocyclic scaffolds (LN6 and LN3O3) towards high-performance Dy(III) single-molecule magnets (SMMs) with pseudo-D6h symmetry is described. Engineering of the macrocycles denticity from LN6 to LN3O3 leads to a mononuclear SMM with a large Ueff value of 1300 K. The experimental results are supported by ab initio calculations, which indicate relaxation of the magnetization via the second-excited state. [ABSTRACT FROM AUTHOR]

The combined use of 2-(2-pyridyl)-1,3-propane-diol (pypdH2) and 2-hydroxymethyl-2-(2-pyridyl)-1,3-propane-diol (pyptH3) in Cu2+/4f chemistry has afforded a new family of isostructural [Cu6M4(pypt)4(pypdH)4(NO3)8] [M = Gd (1), Tb (2), Dy (3), and Y (4)] complexes. These compounds are based on an unprecedented three-layered symmetric [Cu6M4(μ-OR)16]8+ structural core, formed from the connection of the metal ions by bridging alkoxide arms of the organic ligands. Direct current magnetic susceptibility studies for complexes 1–3 revealed the presence of dominant ferromagnetic exchange interactions, suggesting the existence of large spin ground state values. Alternating current magnetic studies indicate the presence of slow-magnetic relaxation in 1–3. [ABSTRACT FROM AUTHOR]

The employment of cyanato (OCN-) group in high oxidation state manganese cluster chemistry, in conjunction with carboxylate ions and the organic chelating/bridging ligand 2-(hydroxymethyl)pyridine (hmpH), is reported. The syntheses, crystal structures, and magnetochemical characterization are described for [Mn16O8(OR)4(OCN)4(O2CMe)12(hmp)6(ROH)2] (R = Me (1), Et (2)) and [Mn18O14(O2CR)18(hmp)4(hmpH)2(H2O)2] (R = Me (3), Et (4)). The 2:1:1:1 reactions of Mn(O2CMe)2·4H2O, hmpH, NaOCN and NEt3 in solvent MeOH or EtOH afford the isostructural complexes [Mn16O8(OR)4(OCN)4(O2CMe)12(hmp)6(ROH)2] (R = Me (1), Et (2)). The [Mn16(μ4-O)4(μ3-O)4(μ-OMe)4(μ3-OR)6(μ-OR)6]10+ core of representative complex 1 comprises a MnII4MnIII4 double-cubane subunit attached on either side to two symmetry-related MnIIMnIII3 defective dicubanes. A similar reaction of Mn(O2CR)2·4H2O, hmpH, NaOCN and NEt3, but in solvent MeCN, led instead to the formation of [Mn18O14(O2CR)18(hmp)4(hmpH)2(H2O)2] (R = Me (3), Et (4)). Compounds 3 and 4 are very similar to each other and can be described as a central [MnIII4(μ-O)6] rodlike subunit attached on either side to two symmetry-related [Mn7O9] subunits. Variable-temperature, solid-state dc and ac magnetic susceptibility studies revealed the presence of predominant antiferromagnetic exchange interactions in all compounds, and possible S = 2 or 1 (for 1 and 2) and S = 0 (for 3 and 4) ground state spin values. The combined results demonstrate the ability of cyanato groups to facilitate the formation of new polynuclear MnII/III complexes with structures different than these obtained from the use of the related azides.

Simple Summary: Subclinical mastitis is a common and economically significant disease that affects dairy sheep production. This study aims to develop and evaluate an advanced algorithmic approach that integrates thermal imaging, statistical texture analysis, and t-distributed stochastic neighbor embedding (t-SNE) to accurately detect subclinical mastitis in dairy sheep. This approach focuses on improving the accuracy and reliability of non-invasive subclinical mastitis detection by using more sophisticated algorithmic procedures than traditional temperature differential methods, thereby enhancing livestock management and animal health monitoring. Subclinical mastitis is a common and economically significant disease that affects dairy sheep production. Thermal imaging presents a promising avenue for non-invasive detection, but existing methodologies often rely on simplistic temperature differentials, potentially leading to inaccurate assessments. This study proposes an advanced algorithmic approach integrating thermal imaging processing with statistical texture analysis and t-distributed stochastic neighbor embedding (t-SNE). Our method achieves a high classification accuracy of 84% using the support vector machines (SVM) algorithm. Furthermore, we introduce another commonly employed evaluation metric, correlating thermal images with commercial California mastitis test (CMT) results after establishing threshold conditions on statistical features, yielding a sensitivity (the true positive rate) of 80% and a specificity (the true negative rate) of 92.5%. The evaluation metrics underscore the efficacy of our approach in detecting subclinical mastitis in dairy sheep, offering a robust tool for improved management practices. [ABSTRACT FROM AUTHOR]

Three new polynuclear clusters with the formulae [Mn10O4(OH)(OMe){(py)2C(O)2}2{(py)2C(OMe)(O)}4(MeCO2)6](ClO4)2 (1), Na[Mn12O2(OH)3(OMe){(py)2C(O)2}6{(py)2C(OH)(O)}2(MeCO2)2(H2O)10](ClO4)8 (2) and [Mn12O4(OH)2{(py)2C(O)2}6{(py)2C(OMe)(O)}(MeCO2)3(NO3)3(H2O)(DMF)2](NO3)2 (3) were prepared from the combination of di‐2‐pyridyl ketone, (py)2CO, with the aliphatic diols (1,3‐propanediol (pdH2) or 1,4‐butanediol (1,4‐bdH2)) in Mn carboxylate chemistry. The reported compounds do not include the aliphatic diols employed in this reaction scheme; however, their use is essential for the formation of 1–3. The crystal structures of 1–3 are based on multilayer cores which, to our knowledge, are reported for the first time in Mn cluster chemistry. Direct current (dc) magnetic susceptibility studies showed the presence of dominant antiferromagnetic exchange interactions within 1–3. Alternating current (ac) magnetic susceptibility studies revealed the presence of out‐of‐phase signals below 3.0 K for 2 and 3 indicating the slow relaxation of the magnetization vector, characteristic of single‐molecule magnets; the Ueff value of 2 was found to be 23 K and the preexponential factor τ0 ~7.6×10−9 s. [ABSTRACT FROM AUTHOR]

The first use of the Schiff base chelate N‐naphthalidene‐o‐aminophenol (naphH2) in Co/Ln chemistry has afforded a family of isostructural [CoIII2LnIII(OMe)2(naph)2(O2CMe)3(MeOH)2] (Ln=Tb, Dy and Er) complexes, revealing a rare {CoIII2Ln(μ3‐OMe)}8+ triangular core composed of two diamagnetic CoIII ions and a 4f‐ion with slightly distorted square antiprismatic geometry. Alternating current (ac) magnetic susceptibility studies revealed that {Co2Dy}, and its magnetic diluted analogue {Co2Dy0.05Y0.95}, behave as mononuclear single‐molecule magnets (SMMs) with similar energy barriers for the magnetization reversal, Ueff, of ~85‐90 K. SMM properties were also detected for {Co2Er}, with the compound exhibiting a Ueff of 18.7 K under an applied magnetic field of 800 Oe. To interpret the experimental magnetic results, ab initio CASSCF/RASSI‐SO and DFT calculations were performed as a means of exploring the single‐ion characteristics of LnIII ions and comprehend the role of the diamagnetic CoIII ions in the magnetization relaxation of the three heterometallic compounds. [ABSTRACT FROM AUTHOR]

The first use of the organic chelate N-hydroxy-1,8-naphthalimide (hynadH) in DyIII chemistry has unveiled access to a synthetic 'playground' composed of four new dinuclear complexes, all of which possess the same planar {Dy2(µ-OR)2}4+ diamond-shaped core, resulting from the bridging and chelating capacity of the hynad-groups. The structural stability of the central {Dy2} core has allowed for the modulation of the peripheral coordination sites of the metal ions, and specifically the NO3 -/hynad-ratio of capping groups, thus affording the compounds [Dy2(hynad)2(NO3)4(DMF)2] (1), (Me4N)2[Dy2(hynad)2(NO3)6] (2), [Dy2(hynad)4(NO3)2(H2O)2] (3), and [Dy2(hynad)6(H2O)2] (4). Because of the chemical and structural modifications in the series 1-4, the DyIII coordination polyhedra are also dissimilar, comprising the muffin (1 and 3), tetradecahedral (2), and spherical tricapped trigonal prismatic (4) geometries. Complexes 1, 2, and 4 exhibit a ferromagnetic response at low temperatures, while 3 is antiferromagnetically coupled. All compounds exhibit out-of-phase (?''M) ac signals as a function of ac frequency and temperature, thus behaving as single-molecule magnets (SMMs), in the absence or presence of applied dc fields. Interestingly, the hynad--rich and nitrato-free complex 4, demonstrates the largest energy barrier (Ueff = 69.62(1) K) for the magnetization reversal which is attributed to the presence of the two axial triangular faces of the spherical tricapped trigonal prism by the negatively charged O-atoms of the hynad-ligands. [ABSTRACT FROM AUTHOR]

The combined use of di-2-pyridyl ketone ((py)2CO) with various diols in Mn cluster chemistry has afforded five new compounds, namely, [Mn11O2(OH)2{(py)2CO2}5(pd)(MeCO2)3(N3)3(NO3)2(DMF)4](NO3)∙2DMF∙H2O (1∙2DMF∙H2O), [Mn11O2(OH)2{(py)2CO2}5(mpd)(MeCO2)3(N3)3(NO3)2(DMF)4](NO3) (2), [Mn12O4(OH)2{(py)2CO2}4(mpd)2(Me3CCO2)4(NO3)4(H2O)6](NO3)2∙2MeCN (3∙2MeCN), [Mn4(OMe)2{(py)2C(OMe)O}2(2-hp)2(NO3)2(DMF)2] (4), and [Mn7{(py)2CO2}4(2-hp)4(NO3)2(DMF)2](ClO4)∙DMF (5∙DMF) ((py)2CO22− and (py)2C(OMe)O− = gem-diol and hemiketal derivatives of di-2-pyridyl ketone, pdH2 = 1,3-propanediol, mpdH2 = 2-metly-1,3-propanediol, 2-hpH2 = 2-(hydroxymethyl)phenol). Complexes 1 and 2 are isostructural, possessing an asymmetric [MnIII5MnII6(μ4-O)(μ3-O)(μ3-OH)(μ-OH)(μ3-OR)2(μ-OR)10(μ-N3)]8+ core. Compound 3 is based on a multilayer [MnIII8MnII4(μ4-O)2(μ3-O)2(μ3-OH)2(μ-OR)12]10+ core, while complex 4 comprises a defective dicubane core. The crystal structure of 5 reveals that it is based on an unusual non-planar [MnIII5MnII2(μ-OR)12]7+ core with a serpentine-like topology. Direct current (dc) magnetic susceptibility studies revealed the presence of dominant antiferromagnetic exchange interactions in complex 3, while ferromagnetic coupling between the Mn ions was detected in the case of compound 5. Fitting of the magnetic data for complex 4 revealed weak antiferromagnetic interactions along the peripheral MnII∙∙∙MnIII ions (Jwb = −0.33 (1) cm−1) and ferromagnetic interactions between the central MnIII∙∙∙MnIII ions (Jbb = 6.28 (1) cm−1). [ABSTRACT FROM AUTHOR]

The synthesis, crystal structures, Mössbauer spectra and variable temperature dc and ac magnetic susceptibility studies of a new family of trinuclear heterometallic Fe3+/Ln3+ complexes, [Fe2Ln(PhCO2)3((py)2CO2)((py)2C(OMe)O)2(NO3)Cl] (Ln = Gd (1/Gd), Tb (1/Tb), Dy (1/Dy), and Ho (1/Ho)), where (py)2CO22− and (py)2C(OMe)O− are the anions of the gem-diol and hemiketal derivatives of di-2-pyridyl ketone, are reported. Compounds 1/Ln are based on an asymmetric "V-shaped" [Fe3+(μ-OR)Ln(μ-OR)2Fe3+]6+ structural core formed from the connection of the two terminal Fe3+ centers to the central Ln3+ ion either through one or two alkoxide groups originating from the alkoxide-type bridging ligands. Direct current magnetic susceptibility studies reveal the presence of weak antiferromagnetic interactions between the Fe3+ ions. Alternating current magnetic studies indicate the presence of a slow-magnetic relaxation process in 1/Dy with an energy barrier Ueff = 6.7 (±0.3) K and a pre-exponential factor, τ0 = 2.2 (±0.4) × 10−7 s. The electronic, magnetic and relaxation properties of the complexes were further monitored by variable temperature 57Fe Mössbauer spectroscopy. At T > 80 K the spectra from the complexes comprise two quadrupole doublets the hyperfine parameters of which reflect the distinct coordination environment of the two Fe3+ terminal sites. At T < 20 K, the Mössbauer spectra for 1/Dy are affected by magnetic relaxation effects. At 1.5 K, the spectrum of 1/Dy comprises well defined magnetic sextets indicating relaxation times slower than the characteristic time of the Mössbauer technique (10−7 s) in agreement with the dynamic magnetic measurements. 1/Gd exhibits broad unresolved magnetic sextets at 1.5 K indicating that the spin relaxation time is of the order of the Mössbauer characteristic time at this temperature. For 1/Tb, 1/Ho the Mössbauer spectra exhibit slight broadening even at the lowest available temperature consistent with magnetic relaxation times less than 10−7 s. [ABSTRACT FROM AUTHOR]

The continuously growing demand for functional plasmonic devices or systems urges the implementation of economical and accelerated nanostructuring techniques. Laser annealing represents a promising approach to address this challenge, given its widespread usage in industry and research, as well as its unique advantages. This study proposes a scalable, rapid, versatile, and cost-efficient method to grow self-assembled nanostructures on metallic ultrathin films and multilayers, with high precision and patterning freedom. By employing industrial-grade equipment, specifically a 1070 nm nanosecond fiber laser and magnetron sputtering system, we directly grew self-assembled nanoparticles on Ag ultrathin films and AgPd multilayers deposited on Corning glass, via laser annealing at ambient conditions. The self-assembled nanoparticles were formed in designated areas by varying several laser parameters and exhibited intense localized surface plasmon resonances. Optical and structural characterization were realized via UV–Vis spectroscopy and atomic force microscopy, respectively. The plasmonic characteristics were found to depend on the initial film thickness and laser annealing parameters. Laser-treated films exhibited remarkable plasmonic behavior, demonstrating that this method does not lack nanostructuring quality while offering scalability and practicality. Further optimization of the laser settings can refine the process and result in an even faster, cheaper, and more qualitative nanostructuring method. [ABSTRACT FROM AUTHOR]

A novel scheme for polarization insensitive GaInNAs-based semiconductor optical amplifiers is proposed in which TE and TM polarization gain is almost equal for GaInNAs quantum wells with GaInAs barriers. The TE and TM amplifiers gain of GaInNAs-based semiconductor optical amplifiers with GaInAs barriers is analyzed.

The theoretical potential of GaInNAs-based semiconductor optical amplifers (SOA) are examined and discussed.

Open‐shell non‐alternant polycyclic hydrocarbons (PHs) are attracting increasing attention due to their promising applications in organic spintronics and quantum computing. Herein we report the synthesis of three cyclohepta[def]fluorene‐based diradicaloids (1–3), by fusion of benzo rings on its periphery for the thermodynamic stabilization, as evidenced by multiple characterization techniques. Remarkably, all of them display a very narrow optical energy gap (Egopt=0.52–0.69 eV) and persistent stability under ambient conditions (t1/2=11.7–33.3 h). More importantly, this new type of diradicaloids possess a low‐lying triplet state with an extremely small singlet–triplet energy gap, as low as 0.002 kcal mol−1, with a clear dependence on the molecular size. This family of compounds thus offers a new route to create non‐alternant open‐shell PHs with high‐spin ground states, and opens up novel possibilities and insights into understanding the structure–property relationships. [ABSTRACT FROM AUTHOR]

Quantum‐dot spin vertical‐cavity surface‐emitting lasers (VCSELs) are a relatively new addition to the spin‐VCSELs literature. The quantum‐dot active region, apart from the usual advantages carried by the quantum confinement in all three directions, offers additional degrees of freedom for the manipulation of the polarization of the emitted light. In, the present contribution, a detailed analysis on the key parameter optimization of optically pumped quantum‐dot spin‐VCSELs is presented. The influence of the spin polarization of the carriers on the polarization control is investigated over a large range of birefringence rate and spin‐relaxation rate values. Precise polarization control is shown in the results, as represented on maps in the plane of pump ellipticity versus birefringence rate. The trajectories on Poincaré sphere reveal a rich polarization behavior ranging from spin amplification to polarization chaos. [ABSTRACT FROM AUTHOR]

A high‐nuclearity {Ni18} complex (1) with a unique ‘flying saucer’ motif has been prepared from the organic chelate, α‐methyl‐2‐pyridine‐methanol (mpmH), in conjunction with bridging azido (N3−) and peroxido (O22−) ligands. Magnetic susceptibility measurements revealed the presence of both ferro‐ and antiferromagnetic exchange interactions between the metal centres in 1, and the stabilization of spin states with appreciable S values at two different temperature regimes. The end‐on bridging azido and alkoxido groups are in all likelihood the ferromagnetic mediators, while the η3:η3:μ6‐bridging peroxides most likely promote the antiparallel alignment of the metals’ spin vectors, yielding an overall non‐zero spin ground state for the centrosymmetric compound 1. Furthermore, the {Ni18} nanosized cluster behaves as a single‐molecule magnet, exhibiting magnetic hysteresis at low temperatures and two relaxation processes at 15 K and 1.3 K, a very rare phenomenon in polynuclear magnetic 3d‐metal clusters. [ABSTRACT FROM AUTHOR]

A new family of radical-bridged compounds, (Cp*2Co)[M2Cl4(dpq)] (M = Fe (1), Co (2), Zn (3)), (dpq = 2,3-di(2-pyridyl)-quinoxaline) is reported. Magnetic studies, DFT and ab initio calculations reveal strong antiferromagnetic metal–radical interactions with coupling constants of J = −213.1 and −218.8 cm−1 for 1 and 2, respectively. [ABSTRACT FROM AUTHOR]

Structural, magnetic and theoretical studies of three octahedral mononuclear DyIII complexes with triphenylphosphine oxide and halide ligands are reported. The Cl− and Br− analogues exhibit SMM behavior with energy barriers of 49.1 K and 70.9 K, respectively under a small dc field. Ab initio calculations were performed, the results of which predict higher energy barriers for iodide containing SMMs. [ABSTRACT FROM AUTHOR]

Self-assembly reactions of CoII ions in the presence of the 2,2-bipyrimidine (bpym) ligand produced both a dinuclear and an octanuclear cation with the nuclearity being governed by hydrogen-bonding versus anion–π interactions between the anions and the ligands. [ABSTRACT FROM AUTHOR]

Two new homoleptic DyIII compounds [Dy(TpMe2)2][DyCl3(TpMe2)]·CH2Cl2 (1) and [Dy(TpMe2)2]I (3) as well as a heteroleptic (NMe4)[DyCl3(TpMe2)] (2) (TpMe2 = tris(3,5-dimethylpyrazolyl)borate) species are reported. Magnetic studies revealed that 1 is a single-molecule magnet (SMM) with an energy barrier of Ueff = 80.7 K with τ0 = 6.2 × 10−7 s under a zero applied field. Compound 3 exhibits a Ueff of 13.5 K with τ0 = 1.6 × 10−6 s under a 0.08 T applied field. Ab initio CASSCF + RASSI-SO calculations were performed to further investigate the magnetic behavior of complexes 1–3. The results support experimental magnetic data for 1 and 3 and indicate that an intermolecular dipolar interaction of (zJ = −0.1 cm−1) is responsible for the SMM behavior of 1. [ABSTRACT FROM AUTHOR]

Two dinuclear lanthanide complexes (Gd and Dy) were prepared and characterized by X-ray, magnetic and computational methods. The Dy analogue shows SMM behavior with an energy barrier of 98.4 K in the absence of an applied dc field. Theoretical calculations were performed on model complexes which support the hypothesis that the energy barrier will increase if the soft-donor atoms S and Se are used in lieu of an O donor. [ABSTRACT FROM AUTHOR]

A new {Dy5} cluster compound has been synthesized and structurally characterized from the initial use of the Schiff base ligand N-naphthalidene-2-amino-5-chlorophenol (nacpH2) in coordination chemistry. The 1:1 reaction between Dy(hpd)3·2H2O and nacpH2, in a solvent mixture comprising CH2Cl2 and MeOH, afforded orange crystals of [Dy5(OH)2(hpd)3(nacp)5(MeOH)5] (1) in 70% yield, where hpd is the anion of 3,5-heptadione. The {Dy5} complex can be described as two vertical {Dy3(3-OH)}8+ triangles sharing a common vertex; such a metal topology is unprecedented in 4f -metal cluster chemistry. Direct current (dc) magnetic susceptibility studies revealed the presence of some weak ferromagnetic exchange interactions between the five DyIII ions at low temperatures. Alternating current (ac) magnetic susceptibility measurements at zero applied dc field showed that complex 1·3MeOH·CH2Cl2 exhibits temperature- and frequency-dependent out-of-phase signals below ~20 K, characteristics of a single-molecule magnet (SMM). The resulting relaxation times were used to construct an Arrhenius-type plot and determine an effective energy barrier, Ueff, of 100 K for the magnetization reversal. The application of a small dc field of 200 Oe resulted in the surpassing of the quantum tunneling process and subsequently the increase of the Ueff to a value of 170 K. The reported results are part of a long-term program aiming at the preparation of structurally and magnetically interesting lanthanide complexes bearing various Schiff base chelating/bridging ligands. [ABSTRACT FROM AUTHOR]

The synthesis of a new family of ferromagnetically-coupled {Ni10} clusters counterbalanced by various [Ln(NO3)5]2− ions is herein described. The resulting compounds are organic chelate-free and the metal ions are exclusively bridged by end-on azido ligands to stabilize a beautiful disk-like topology reminiscent of the structure of the brucite mineral. [ABSTRACT FROM AUTHOR]