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The quantum nuclear kinematic interactions with electrons (or nonadiabatic interactions) are the inherent driving force that possibly causes a mixture of the adiabatic electronic states in molecules. Particularly in systems whose electron wavepackets lie in a densely quasi-degenerate electronic-state manifold where many-dimensional and many-state nonadiabatic interactions last continually, we have found before that those extensive mixings can lead to a quantum electronic-state chaos [K. Takatsuka and Y. Arasaki, J. Chem. Phys. 159, 074110 (2023)]. This chaos of electron dynamics is a new kind yet generic. This Communication identifies the mathematical/physical mechanism of this class of chaos by means of the collective coordinate analysis of the nonadiabatic interactions, along with the numerical applications to excited states of boron clusters. Some physical consequences of the present chaos are also discussed. [ABSTRACT FROM AUTHOR]

Synthetic antiferromagnetic (SAF) nanoplatelets (NPs) with perpendicular magnetic anisotropy based on archetype SAF structures, e.g., Pt/Co/Ru/Co/Pt are of particular interest for torque-related bio-applications due to their large uniaxial magnetic anisotropy. However, when the diameter of the NPs is reduced, the magnetic properties change. For instance, the coercive field increases and starts to vary strongly from NP to NP in a batch due to an increased variation in the reversal probability dominated by local defects. In this study, we investigate how the concentration of boron (B) in Co 1 − x B x affects the switching properties of NPs, because the addition of B renders the Co layer amorphous and hence introduces more defects. Moreover, it reduces variations in local crystalline anisotropy making the magnetic properties of the NPs more soft. Specifically, we show that the coercivity of the NPs decreases with higher B concentration. This decrease is explained by two mechanisms: (i) the loss of interfacial anisotropy due to less Co–Pt hybridization at the Pt–Co interface and (ii) an increase in the surface's magnetic domain nucleation site density leading to a narrower distribution of the coercivity of an ensemble of NPs. This understanding will greatly help the field of NP-torque related applications as the spread in applied torque from the NPs to their surroundings can be homogenized. [ABSTRACT FROM AUTHOR]

Excess minority carriers create boron-related recombination centers that degrade the efficiency of the non-particle-irradiated silicon solar cells. However, the carrier-induced reactions among the radiation-induced defects are poorly understood for devices exposed to particle radiation. This study investigates the structure, electronic properties, formation and annihilation mechanisms, and diffusion dynamics of the carrier-induced defects in particle-irradiated boron-doped silicon using density-functional modeling and junction spectroscopy. By revisiting the ground-state structures of the boron-di-interstitial clusters (B I 2), we find that the calculated acceptor and donor levels of such defects agree well quantitatively with the carrier-induced deep-level transient spectroscopy (DLTS) hole emission signatures at 0.43 and 0.53 eV above the valence band edge (E v), respectively. We also find that the formation of B I 2 is thermally activated by an energy of 0.50 eV, which we explain theoretically by the reduction of the migration barrier of mono-interstitials to 0.53 eV in the presence of excess minority carriers. Moreover, we discover that the B I 2 are potentially mobile with a migration barrier of 1.18 eV, contrary to the present understanding. [ABSTRACT FROM AUTHOR]

Boron-based compounds have triggered substantial attention due to their multifunctional properties, incorporating excellent hardness and superconductivity. While tetragonal metal borides LiB4 and NaB4 with BaAl4-type structure and striking clathrate boron motif have been induced under compression, there is still a lack of deep understanding of their potential properties at ambient pressure. We herein conduct a comprehensive study on I4/mmm-structured LiB4 and NaB4 under ambient pressure via first-principles calculations. Remarkably, both LiB4 and NaB4 are found to possess high Vickers hardness of 39 GPa, which is ascribed to the robust boron framework with strong covalency. Furthermore, their high hardness values together with distinguished stability make them highly potential superhard materials. Meanwhile, electron–phonon coupling analysis reveals that both LiB4 and NaB4 are conventional phonon-mediated superconductors, with critical temperatures of 6 and 8 K at 1 atmosphere pressure (atm), respectively, mainly arising from the coupling of B 2p electronic states and the low-frequency phonon modes associated with Li-, Na-, and B-derived vibrations. This work provides valuable insights into the mechanical and superconducting behaviors of metal borides and will boost further studies of emergent borides with multiple functionalities. [ABSTRACT FROM AUTHOR]

Boron-based compounds have triggered substantial attention due to their multifunctional properties, incorporating excellent hardness and superconductivity. While tetragonal metal borides LiB4 and NaB4 with BaAl4-type structure and striking clathrate boron motif have been induced under compression, there is still a lack of deep understanding of their potential properties at ambient pressure. We herein conduct a comprehensive study on I4/mmm-structured LiB4 and NaB4 under ambient pressure via first-principles calculations. Remarkably, both LiB4 and NaB4 are found to possess high Vickers hardness of 39 GPa, which is ascribed to the robust boron framework with strong covalency. Furthermore, their high hardness values together with distinguished stability make them highly potential superhard materials. Meanwhile, electron–phonon coupling analysis reveals that both LiB4 and NaB4 are conventional phonon-mediated superconductors, with critical temperatures of 6 and 8 K at 1 atmosphere pressure (atm), respectively, mainly arising from the coupling of B 2p electronic states and the low-frequency phonon modes associated with Li-, Na-, and B-derived vibrations. This work provides valuable insights into the mechanical and superconducting behaviors of metal borides and will boost further studies of emergent borides with multiple functionalities. [ABSTRACT FROM AUTHOR]

An anion-responsive boron-containing π-conjugated polymer was synthesized via the Sonogashira coupling polymerization. The 11B NMR, UV/vis absorption, and fluorescence spectra confirmed the formation of an anion complex between the polymer and tetrabutylammonium fluoride (TBAF). Thin films were then prepared either by the pre-addition method, where the thin film was prepared using a solution of the polymer and TBAF, or by the post-addition method, where the polymer thin film was treated with an aqueous TBAF solution. The contact angle measurements revealed an enhancement in wettability with both methods. Consequently, wettability can be controlled via anion-complex formation at the surface. [ABSTRACT FROM AUTHOR]

Weather and climate uncertainties significantly impact crop and food production, particularly in the Bihar region of India. Crop cultivation in this region faces significant risks due to several climatic challenges: rising minimum temperatures in the winter (rabi), extreme temperatures in the spring, intense rainfall, and extended dry spells during the kharif ;(monsoon) season. The growth and development of the plants majorly depend on the climatic and nutrient factors. The plant uptake and utilization of nutrients are surprisingly reliant on the weather conditions. Therefore, understanding the interaction of climatic factors and nutrient application methods is crucial for achieving higher growth and yield stewardship. A two-year field experiment was conducted from 2019 to 2021 in the riverine area (Diara) of Bihar, India, to evaluate the relationship between weather parameters and application methods of Molybdenum and Boron on the dry matter production (DMP) and grain yield of chickpea. Six different application methods of Boron and Molybdenum were tested. The study aimed to identify the ideal micronutrient application methods for chickpea production in the rabi season under the Diara ;(riverine) area. Results indicated that the combination of boron basal + molybdenum seed treatment produced the highest grain yield (1740 kg ha−1) and dry matter production (5.81 g plant−1) at all phenological phases, performing on par with boron basal + molybdenum foliar application for both years. Concerning the weather parameters, the correlation studies showed that all the direct weather parameters and agrometeorological indices showed positive and negative effects (p =.05) on DMP and grain yield of chickpea during both years. This study contributes to the development of site-specific application methods for molybdenum and boron, identifies optimal sowing times, minimizes the negative impacts of climate change, and maximizes chickpea production in the riverine (Diara) area of Bihar. [ABSTRACT FROM AUTHOR]

Acenes are attractive as building blocks for low gap organic materials with applications, for example, in organic light emitting diodes, solar cells, bioimaging and diagnostics. Previously, we have shown that modification of dipyridylanthracene via B–N Lewis pair fusion (BDPA) strongly redshifts the emission, while facilitating self‐sensitized reactivity toward O2 to reversibly generate the corresponding endoperoxides. Herein, we report on the further expansion of the π‐system of BDPA to a vinyl‐substituted monomer, vinylene‐bridged dimer, and a polymer with an average of 20 chromophores. The extension of π‐conjugation results in largely reduced band gaps of 1.8 eV for the dimer and 1.7 eV for the polymer, the latter giving rise to NIR emission with a maximum at 731 nm and an appreciable quantum yield of 7 %. Electrochemical and computational studies reveal efficient delocalization of the lowest unoccupied molecular orbital (LUMO) along the pyridyl‐anthracene‐pyridyl axis, which results in effective electronic communication between BDPA units, selectively lowers the LUMO, and ultimately narrows the band gap. Time‐resolved emission and transient absorption (TA) measurements offer insights into the pertinent photophysical processes. Extension of π‐conjugation also slows down the self‐sensitized formation of endoperoxides, while significantly accelerating the thermal release of singlet oxygen to regenerate the parent acenes. [ABSTRACT FROM AUTHOR]

Based on the EAST equilibrium, the effects of boron (B) and neon (Ne) injected at different locations on the target heat load, and the distributions of B and Ne particles were investigated by transport code SOLPS-ITER. It was found that the B injection was more sensitive to the injection location for heat flux control than impurity Ne. The high electron and ion densities near the inner target in the discharge with impurity B injected from over X -point (R 1) led to plasma detachment only at the inner target, and the localized B ions in the cases with injection from outer target location (R 2) and upstream location (R 3) led to far-SOL detachment at the outer target, but not at the inner target. In contrast, for Ne, the spatial distributions of Ne ions and electrons were found to be similar in all the cases at the three injection locations, and the detached plasma was achieved at the inner target and the electron temperature was reduced at the outer target. For locations R 2 and R 3, impurity B showed a more pronounced effect on the heat flux at the far-SOL of the outer target. Further analysis indicated that Ne atoms came mainly from the recycling sources, whereas B atoms came mainly from injection, and that their distinct atomic distributions resulted from the difference in the ionization threshold and ionization mean free path. In addition, the radiation proportion of B in the divertor region was larger than that of Ne when the total radiation power was similar, which suggests that B has less influence on the core region. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Previous studies have demonstrated linear polymers embedded with B←N units display efficient photocatalytic hydrogen evolution performance, but their limited structural tunability restricts photogenerated carrier dynamics modulation. Current researches mainly focus on linear polymers, while the study of B←N units in the field of two‐dimension conjugated polymers (2DCPs) photocatalytic hydrogen evolution remains an uncultivated ground. Herein, three 2DCPs containing B←N units were synthesized and their photocatalytic hydrogen production performance was investigated. Among them, the BN‐Tz exhibited the best property with a hydrogen production rate of 89.5 μmol·h–1, while BN‐Ph and BN‐TPB were only 26.4 and 8.5 μmol·h–1, respectively. Comprehensive analyses showed that the remarkable photocatalytic ability of BN‐Tz catalyst was mainly attributed to its superior transport and separation of photogenerated carriers, as well as the ability to construct a stronger built‐in electric field and better planarity. Meanwhile, it was found that the manipulation of the electronic properties of the structures connected to the B←N unit could effectively regulate the molecular polarity, thus achieving the control of the electronic structure of the materials. This work extends the application of materials containing B←N units in photocatalysis and lays a good foundation for the subsequent design of photocatalysts containing B←N units. [ABSTRACT FROM AUTHOR]

The regulatory role of estrogen receptor beta (ERβ) and the JNK signaling pathway in the effect of high-dose boron on rat splenic lymphocytes has been examined by measuring proliferation, apoptosis, and immune function. The results showed that, compared with the control group, the addition of high-dose boron (40 mmol/L) reduced the proportion of CD3+, CD4+, and CD8+ T lymphocytes, the concentrations of IgG, IL-2, IFN-γ, and IL-4, the proliferation rate of splenic lymphocytes, and the expression levels of PCNA and Bcl-2 mRNA (P < 0.01 or P < 0.05), and increased the apoptosis rate of splenic lymphocytes, caspase-3, and BAX mRNA expression levels (P < 0.01 or P < 0.05). After specific blocking of ERβ, the addition of high-dose boron could not reduce the proportion of CD8+ T lymphocytes, the concentrations of IgG and cytokines IL-2, IFN-γ, and IL-4, the lymphocyte proliferation rate, or PCNA mRNA expression levels, nor could it increase BAX mRNA expression levels. After specific blocking of JNK, the addition of high-dose boron could not increase BAX mRNA expression levels. However, after specific blocking of ERβ and JNK, the addition of high-dose boron could neither reduce the proportion of CD4+ and CD8+ T lymphocytes, the concentrations of IgG and IL-2 (P > 0.05), nor increase caspase-3 and BAX mRNA expression levels (P < 0.01). The results suggest that the ERβ-mediated JNK signaling pathway participates in regulating the effects of high-dose boron on the expression of genes related to the proliferation and apoptosis of rat splenic lymphocytes. [ABSTRACT FROM AUTHOR]

In this paper, boron (B)‐doped biphasic calcium phosphate (BCP)/poly(vinylidene fluoride) (PVDF) membrane scaffolds were developed by the combination of non‐solvent induced phase separation and lyophilization processes. In addition, the effects of the synthesized B‐incorporated BCP powders on the properties of the fabricated scaffolds were investigated. The physicochemical and morphological properties of the scaffolds were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy. The physical properties were evaluated by surface wettability and swelling measurements, whereas the mechanical properties were investigated by tensile strength measurements. The thermal behavior was determined by differential scanning calorimetry, the β‐crystallization ratio was calculated by FTIR, and the β‐phase structure was characterized by X‐ray diffraction. The bioactivity was evaluated in the simulated body fluid, and the cytotoxicity of the scaffolds was also investigated by performing in vitro cell culture experiments. The results showed that the incorporation of B into the PVDF matrix improved the hydrophilicity while reducing the degree of swelling of the scaffolds. Tensile strength was slightly reduced by the powder content, but yet the strength of all scaffolds was mechanically compatible with native bone. Increasing the B content up to 0.5 and 1 wt.% was improved the thermal properties, the β‐crystalline phase fraction, and thus the piezoelectricity. Furthermore, B‐doped BCP/PVDF‐based scaffolds significantly promoted bioactivity, cell viability, and proliferation without cytotoxicity, compared to the PVDF scaffold, depending on the B content. In conclusion, our results indicate that the PVDF‐based composites in the form of membrane scaffolds that support bone growth have the potential to be highly sought‐after candidates in the field of biomedical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Preparation of interconnected hollow carbon spheres functionalized with B and Tb single atoms. • B doping increases the Lewis acidity of Tb, promoting the occurrence of rate-determining step of ring-opening reaction. • The prepared TbN 4 B 2 /C can adsorb full band light to achieve efficient photothermal conversion. • The CO 2 cycloaddition reaction with using TbN 4 B 2 /C as catalyst is a photothermal synergistic catalytic mechanism. Nowadays, it is becoming increasingly urgent to lower the escalating carbon dioxide (CO 2) to reduce greenhouse effect. Fortunately, it is an ideal strategy by using the inexhaustible solar energy as the driving force to manipulate the cycloaddition reaction, the atomic efficiency of which is 100 %. This work represents the first attempt on utilization of rare-earth metal Tb with atomic dispersion, and the structure of Tb coordinated with 4 N -atoms and 2B-atoms was constructed on interconnected carbon hollow spheres. The introduction of electron-deficient B reduces the electron density of Tb, thereby boosting Lewis acidity and promoting the occurrence of ring-opening reaction. The mechanism exploration enunciates that TbN 4 B 2 /C is a photothermal synergistic catalyst, the combined action of photogenerated electrons and strong Lewis acidic site of Tb reduces the free energy of the rate-determining step, and then improving the yield of cyclic carbonate up to 739 mmol g-1h−1. [ABSTRACT FROM AUTHOR]

Energy conservation and emission reduction are the general trend of the present world. In this study, a catalyst of 3WSH based on the waste recycle of waterworks sludge (WS) and Chinese herbs was prepared using one-step calcination treatment and then characterized by SEM, XRD, XPS, FTIR and BET. The catalytic performance of 3WSHB for activating potassium persulfate (PDS) was evaluated through the degradation of Safranine T (ST) in the presence of boron powder (B). The effects of vital parameters on ST removal were systematically studied, including PDS concentration, 3WSHB dosage, initial solution pH, B dosage, temperature and coexisting cations. The highest efficiency of ST removal was up to 93.0% under the optimal condition with 1.85 mM of PDS, 0.3 g/L of 3WSHB, 0.35g/L of B, 7 of pH. EPR and free radical quenching experiments demonstrated that •OH was the dominant reactive oxygen species for ST degradation in the PDS/3WSHB/B system. Moreover, the intermediates determined by HPLC-MS indicated that the oxidization of benzene ring substituents in ST and a hydrogen abstraction by electron transfer might occur during ST degradation. The dissatisfied reuse performance of 3WSHB might be attributed to its low Fe content and simple reusing way. The results demonstrate the effectiveness of WS recycling and reuse in the field of pollutant remediation. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Previous studies have demonstrated linear polymers embedded with B←N units display efficient photocatalytic hydrogen evolution performance, but their limited structural tunability restricts photogenerated carrier dynamics modulation. Current researches mainly focus on linear polymers, while the study of B←N units in the field of two‐dimension conjugated polymers (2DCPs) photocatalytic hydrogen evolution remains an uncultivated ground. Herein, three 2DCPs containing B←N units were synthesized and their photocatalytic hydrogen production performance was investigated. Among them, the BN‐Tz exhibited the best property with a hydrogen production rate of 89.5 μmol·h–1, while BN‐Ph and BN‐TPB were only 26.4 and 8.5 μmol·h–1, respectively. Comprehensive analyses showed that the remarkable photocatalytic ability of BN‐Tz catalyst was mainly attributed to its superior transport and separation of photogenerated carriers, as well as the ability to construct a stronger built‐in electric field and better planarity. Meanwhile, it was found that the manipulation of the electronic properties of the structures connected to the B←N unit could effectively regulate the molecular polarity, thus achieving the control of the electronic structure of the materials. This work extends the application of materials containing B←N units in photocatalysis and lays a good foundation for the subsequent design of photocatalysts containing B←N units. [ABSTRACT FROM AUTHOR]

Background and aims Methods Results Conclusion Low boron (B) availability is associated with strongly weathered, coarse‐textured, and low organic matter soils, widespread in sub‐Saharan Africa (SSA). It is unknown to what extent B fertilization can increase maize yields in SSA. This study aims to understand the soil properties controlling B availability to field‐grown maize.Boron fertilizer omission trials with maize were executed at 15 sites in Kenya, Zambia, and Zimbabwe. Yield, B uptake, and soil parameters potentially relevant for B availability, including extractable soil B (hot water, 0.01 M CaCl2, and 0.43 M HNO3), were determined.Soil B pools were strongly intercorrelated and were positively correlated with organic carbon, suggesting the relevance of organic matter for soil B availability. Soil parameters described limited variation in B uptake and the yield response to B fertilization. Boron fertilization did not increase yields in any of the 15 sites but increased uptake in 11 sites. Yields were reduced through B fertilization in five sites, likely because B application induced toxicity. No clear critical soil or plant B concentrations indicating deficiency could be derived, but positive yield responses to B fertilization were absent with hot water B levels above 0.69 mg kg−1.Assessing B fertilizer needs in maize grown in tropical soils based on soil or plant tissue concentrations remains challenging. Improving soil organic matter status could potentially alleviate B deficiency in crops when present. Recommendations are given to overcome the identified challenges associated with studying B availability in tropical soils. [ABSTRACT FROM AUTHOR]

SUMMARY Boron (B) is an important limiting factor for plant growth and yield in saline soils, but the underlying molecular mechanisms remain poorly understood. In this study, we found that appropriate B supply obviously complemented rapeseed (Brassica napus L.) growth under salinity accompanied by higher biomass production and less reactive oxygen species accumulation. Determination of Na+ content in shoots and roots indicated that B significantly repressed root‐to‐shoot Na+ translocation, and non‐invasive micro‐tests of root xylem sap demonstrated that B increased xylem Na+ unloading in the roots of rapeseed plants under salinity. Comparative transcriptomic profiling revealed that B strongly upregulated BnaHKT1s expression, especially BnaA2.HKT1, in rapeseed roots exposed to salinity. In situ hybridizations analysis showed that BnaA2.HKT1 was significantly induced in root stelar tissues by high B (HB) under salinity. Green fluorescent protein and yeast heterologous expression showed that BnaA2.HKT1 functioned as a plasma membrane‐localized Na+ transporter. Knockout of BnaA2.HKT1 by CRISPR/Cas9 resulted in hypersensitive of rapeseed plants to salinity even under HB condition, with higher shoot Na+ accumulation and lower biomass production. By contrast, overexpression of BnaA2.HKT1 ameliorated salinity‐induced growth inhibition under B deficiency and salinity. Overall, our results proposed that B functioned as a positive regulator for the rapeseed growth and seed production under salt stress through facilitating BnaA2.HKT1‐mediated root xylem Na+ unloading. This study may also provide an alternative strategy for the improvement of crop growth and development in saline soils. [ABSTRACT FROM AUTHOR]

Herein, the electronic and piezoelectric properties of different types of (chair form and boat form) H/F‐functionalized boron phosphide (BP) sheets are examined by density‐functional theory calculations. After H/F atoms adsorb on both sides of pristine hexagonal boron phosphide (h‐BP) cell, the functionalized BP structure undergoes significant flatness distortion. The H/F‐functionalized BP sheets are predicted to be thermodynamically and dynamically stable. According to the calculations, it is demonstrated that chemical functionalization is an effective method to modulate the bandgap of h‐BP in a wide range (0.80–3.63 eV). The chair form F–BP–H shows large e31 (−0.7 × 10−10 C m−1) and d31 (−0.68 pm V−1). The d11 of boat form F–BP–H is 4.32 pm V−1, which is 95.5% higher than the pristine h‐BP monolayer (2.21 pm V−1). The study provides a possible way to modulate the intrinsic characteristics of the pristine h‐BP sheet, which would broaden its potential applications in the future for wider range of applications. [ABSTRACT FROM AUTHOR]

First-principles simulations are conducted to explore the structural stability, electronic properties, and optical responses of pristine and boron- or nitrogen-doped monolayers graphene. The computed electronic density of states revealed that the substitutional doping of boron impurity atoms on monolayer graphene (MLG) shifts the Dirac point upward, although the substitution of nitrogen impurity atoms in graphene pushes the Dirac point downward the Fermi level. This could exhibit that upon the doping of MLG with boron or nitrogen, respectively, p-type or n-type semimetal is acquired. The overall optical spectral properties of the substituted graphene with boron or nitrogen atoms are simulated and compared with the optical spectra results of pure graphene. The optical features of pristine and doped MLG are determined by taking the interband and intra-band transitions into account ranging from the far-infrared to the ultraviolet regime of the electromagnetic radiation. A remarkable red shift in the optical spectra of the doped MLG towards the visible regime of radiation is established. An enhanced reflectivity illustrated that concentration-dependent optical properties of boron and nitrogen-doped MLG happen at lower electromagnetic radiation regimes. In addition, we explored the thermoelectric behaviors of the pristine/doped graphene monolayers with 4 × 4 supercells. We found a significant improvement in the electrical conductivity of graphene when doped with boron or nitrogen impurities. However, an increase in the electrical conductivity has textured a decrease in the Seebeck coefficients. Improvement in the electrical conductivity is attributed to an interesting effect on the graphene monolayers' power factor (PF). These findings indicate a positive impact of the dopants on the thermoelectric properties of graphene monolayers and reveal that they are potential materials for thermoelectric applications and nanodevices. [ABSTRACT FROM AUTHOR]

Boron, essential for plant growth, necessitates precise regulation due to its potential toxicity. This regulation is achieved by borate transporters (BORs), which are homologous to the SLC4 family. The Arabidopsis thaliana Bor1 (AtBor1) transporter from clade I undergoes slow regulation through degradation and translational suppression, but its potential for fast regulation via direct activity modulation was unclear. Here, we combine cryo-electron microscopy, mutagenesis, and functional characterization to study AtBor1, revealing high-resolution structures of the dimer in one inactive and three active states. Our findings show that AtBor1 is regulated by two distinct mechanisms: an autoinhibitory domain at the carboxyl terminus obstructs the substrate pathway via conserved salt bridges, and phosphorylation of Thr410 allows interaction with a positively charged pocket at the cytosolic face, essential for borate transport. These results elucidate the molecular basis of AtBor1's activity regulation and highlight its role in fast boron level regulation in plants. Boron is essential for plant growth, and its transport is tightly regulated. Here, the authors present structures of the borate transporter AtBor1 in both inactive and active states, revealing how its C-terminal domain mediates autoinhibition. [ABSTRACT FROM AUTHOR]

Closo-Hexaborate (closo-B6H62−) can engage in nucleophilic substitution reactions with a wide variety of alkyl electrophiles. The resulting functionalized boron clusters undergo oxidative electrochemical deconstruction, selectively cleaving B–B bonds while preserving B–C bonds in these species. This approach allows the conversion of multinuclear boron clusters into single boron site organoboranes. Trapped boron-based fragments were isolated from the electrochemical cluster deconstruction process, providing further mechanistic insights into the developed reaction. [ABSTRACT FROM AUTHOR]

Skeletal editing of single-atom insertion to basic chemicals has been demonstrated as an efficient strategy for the discovery of structurally diversified compounds. Previous endeavors in skeletal editing have successfully facilitated the insertion of boron, nitrogen, and carbon atoms. Given the prevalence of oxygen atoms in biologically active molecules, the direct oxygenation of C-C bonds through single-oxygen-atom insertion like Baeyer-Villiger reaction is of particular significance. Herein, we present an approach for the skeletal modification of styrenes using O2 via oxygen insertion, resulting in the formation of aryl ether frameworks under mild reaction conditions. The broad functional-group tolerance and the excellent chemo- and regioselectivity are demonstrated in this protocol. A preliminary mechanistic study indicates the potential involvement of 1,2-aryl radical migration in this reaction. The direct oxygenation of C–C bonds through single-oxygen-atom insertion like the Baeyer-Villiger reaction is of particular significance. Herein, the authors present an approach for the skeletal modification of styrene using O2 via oxygen insertion, resulting in the formation of aryl ether frameworks under mild reaction conditions. [ABSTRACT FROM AUTHOR]

The carbon-based metal-free catalyst was prepared by the hydrothermal method. The boron functionalized carbon dots modified g-C3N4 (BCDs/g-C3N4) photoelectrode showed excellent photoelectrocatalysis performance. Due to boron doping, the agglomeration of the complex is effectively inhibited, the specific surface area is increased and the number of active sites is increased. In addition, the boron atoms in BCDs interact closely with the nitrogen atoms of g-C3N4, which accelerates the electron transfer rate between the carbon dots and g-C3N4. Compared with g-C3N4, the photocurrent intensity of BCDs/g-C3N4 increases by 2.26 times. Finally, the photoelectrocatalytic (PEC) degradation efficiency of phenol by BCDs/g-C3N4 reached about 100% within 180 min. The BCDs/g-C3N4 photoelectrode has good acid and alkali corrosion resistance, universal applicability and cyclic stability. [ABSTRACT FROM AUTHOR]

This study aimed to quantitatively analyze the combustion process of a boron/ethanol nanofuel droplet through optical and spectroscopic observations. Boron nanoparticles were added to ethanol at concentrations of 0 %, 2 %, 4 %, and 6 % by weight. Experiments were conducted under atmospheric pressure, and the droplet diameter was controlled at 1.1 ± 0.1 mm. Results indicated that the combustion of the boron nanofuel droplet was similar to that of the 0 wt.% boron nanofuel droplets at the beginning of the experiment, but the former actively combusted as the experiment progressed. Mass ejections, such as puffing and microexplosions, were observed at the late stage of combustion. Spectroscopic measurements revealed that boron oxide emissions were predominant at the late stage of droplet combustion, and this emission trend varied with changes in the boron concentration. Photomultiplier tube data obtained through a bandpass filter of 550 nm demonstrated temporal intensity fluctuations during combustion. The overall signal intensity was enhanced by high boron concentrations. [ABSTRACT FROM AUTHOR]

As a neighbor of carbon in the periodic table, boron exhibits versatile structural and electronic configurations, with its allotropes predicted to possess intriguing structures and properties. Since the experimental realization of two‐dimensional (2D) boron sheets (borophene) on Ag(111) substrates in 2015, the experimental study of the realization and characteristics of borophene has drawn increasing interest. In this review, we summarize the synthesis and properties of borophene, which are mainly based on experimental results. First, the synthesis of borophene on different substrates, as well as borophane and bilayer borophene, featuring unique phases and properties, are discussed. Next, the chemistry of borophene, such as oxidation, hydrogenation, and its integration into heterostructures with other materials, is summarized. We also mention a few works focused on the physical properties of borophene, specifically its electronic properties. Lastly, the brief outlook addresses challenges toward practical applications of borophene and possible solutions. [ABSTRACT FROM AUTHOR]

Boron is a naturally occurring trace chemical element. High concentrations of boron in nature can adversely affect biological systems and cause severe pollution to the ecological environment. We examined a method to effectively remove boron ions from water systems using sugarcane bagasse biochar from agricultural waste with NH3 nanobubbles (10% NH3 and 90% N2). We studied the effects of the boron solution concentration, pH, and adsorption time on the adsorption of boron by the modified biochar. At the same time, the possibility of using magnesium chloride and NH3 nanobubbles to enhance the adsorption capacity of the biochar was explored. The carbonization temperature of sugarcane bagasse was investigated using thermogravimetric analysis. It was characterized using XRD, SEM, and BET analysis. The boron adsorption results showed that, under alkaline conditions above pH 9, the adsorption capacity of the positively charged modified biochar was improved under the double-layer effect of magnesium ions and NH3 nanobubbles, because the boron existed in the form of negatively charged borate B(OH)4− anion groups. Moreover, cations on the NH3 nanobubble could adsorb the boron. When the NH3 nanobubbles with boron and the modified biochar with boron could coagulate each other, the boron was removed to a significant extent. Extended DLVO theory was adopted to model the interaction between the NH3 nanobubble and modified biochar. The boron adsorption capacity was 36 mg/g at room temperature according to a Langmuir adsorption isotherm. The adsorbed boron was investigated using FT-IR and XPS analysis. The ammonia could be removed using zeolite molecular sieves and heating. Boron in an aqueous solution can be removed via adsorption with modified biochar with NH3 nanobubbles and MgCl2 addition. [ABSTRACT FROM AUTHOR]

Maize production and quality are affected by infection with plant pathogens. One of the maize's essential and main diseases is downy mildew caused by Peronosclerospora spp. Downy mildew is a limiting factor in increasing production and can reduce production by 80-100%. It is because the affected plant cannot produce cobs. Pathogens obtain nutrients from the host cell, which can kill the cell and damage the surrounding tissues, resulting in visible downy mildew symptoms. Boron (B) plays a role in forming phloem, increasing the fruit's number, weight, bunch weight, and diameter. The primary function of B at the molecular level is the cross-linking of pectin in the plant cell wall. Ramnogalacturonan II (RG II) is a pectic polysaccharide that contributes to the mechanical strength and properties of the primary wall cross-linked by borate diesters. Phosphorus (P) controls the downsides in the greenhouse and field conditions. This study aims to measure changes in chlorophyll index, P and B uptakes in downy mildew affected plants. The field experiment used a group randomized design with six natural phosphate (FA) application treatments and four groups of borax doses as replicates. The results showed that the downy mildew decreased the chlorophyll index of the leaves at different levels of attack. The results of P concentration according to the position of healthy plant leaves were significantly different due to P treatment. In contrast to concentration B, there is no real difference. P and B uptake results in downy mildew-infested plants showed a significant difference only in P uptake in leaves with 1 FA treatment. [ABSTRACT FROM AUTHOR]

The history of grain refinement with AlB2 in Al–Si and Al–Si–Cu casting alloys is reconsidered in light of findings published recently by Zheng and co-workers. When using boron as a grain refiner, some problems may be encountered. These are considered briefly. Fundamental aspects of grain refinement are also discussed and useful future experiments proposed. [ABSTRACT FROM AUTHOR]

The crystal structures of 16 boron subphthalocyanines (BsubPcs) with structurally diverse axial groups were analyzed and compared to elucidate the impact of the axial group on the intermolecular π–π interactions, axial‐group interactions, axial bond length and BsubPc bowl depth. π–π interactions between the isoindole units of adjacent BsubPc molecules most often involve concave–concave packing, whereas axial‐group interactions with adjacent BsubPc molecules tend to favour the convex side of the BsubPc bowl. Furthermore, axial groups that contain O and/or F atoms tend to have significant hydrogen‐bonding interactions, while axial groups containing arene site(s) can participate in π–π interactions with the BsubPc bowl, both of which can strongly influence the crystal packing. Bulky axial groups did tend to disrupt the π–π interactions and/or axial‐group interactions, preventing some of the close packing that is seen in BsubPcs with less bulky axial groups. The atomic radius of the heteroatom bonded to boron directly influences the axial bond length, whereas the axial group has minimal impact on the BsubPc bowl depth. Finally, the crystal growth method did not generally appear to have a significant impact on the solid‐state arrangement, with the exception of water occasionally being incorporated into crystal structures when hygroscopic solvents were used. These insights can help with the design and fine‐tuning of the solid‐state structures of BsubPcs as they continue to be developed as functional materials in organic electronics. [ABSTRACT FROM AUTHOR]

The copper‐catalyzed azide alkyne [3+2]‐cycloaddition (CuAAC) reaction of organoboranes represents an attractive area of research within the field of click chemistry, with diverse applications in organic synthesis, medicinal chemistry, or materials science. Despite the potential issues caused by the copper insertion into the carbon‐boron bond, significant progress has been made to harness the reactivity of organoboron compounds in CuAAC. This review provides an overview of the catalytic methods reported for CuAAC with various organoboranes, discussing the stability of the boron group and highlighting recent advancements in this area. [ABSTRACT FROM AUTHOR]

m‐Pyripentaphyrins(1.0.0.0.0) were synthesized by Suzuki‐Miyaura coupling of 3,5‐bis(5‐borylpyrrol‐2‐yl)‐BODIPY with 2,6‐dibromopyridine. Upon treatment with PhBCl2, pyripentaphyrin 1 provided mono‐ and bis‐BIII complexes sequentially. The Mono‐BIII complex shows a distorted tetrahedral coordinated BIII with a σ‐phenyl ligand on the BIII and the bis‐BIII complex shows an additional distorted tetrahedral coordinated BIII with a B−H bond. Bromination of the pyripentaphyrins with N‐bromosuccinimide (NBS) resulted in regioselective formation of 8‐bromopyripentaphyrins, which were dimerized to 8,8'‐linked dimers by reductive coupling with Ni(cod)2. While all these pyripentaphyrins are nonaromatic, they exhibit characteristic broad absorption bands at long wavelength near the NIR region, indicating the presence of effective macrocyclic conjugation. [ABSTRACT FROM AUTHOR]

Key message: Boron is essential for plants, but excess can induce toxicity. Boron (B) is a vital micronutrient for plants, but excess B can induce toxicity symptoms and reduce crop yields. B bioavailability depends on soil properties, including clay type, pH, and organic matter content. Symptoms of B toxicity include reduced shoot and root growth, leaf chlorosis and necrosis, impaired photosynthesis, and disrupted pollen development. This review paper examines the current knowledge on B toxicity mechanisms, tolerance strategies, and management approaches in plants. This review covers (1) factors affecting B bioavailability; (2) toxicity symptoms in plants; (3) uptake, transport, and detoxification mechanisms; and (4) strategies. To mitigate toxicity, plants reduce B uptake, activate efflux transporters, compartmentalize B, and enhance antioxidant systems. On the basis of this review, future research should focus on identifying novel tolerance mechanisms, exploring genetic strategies for improved B management, and developing innovative agronomic interventions. These insights will facilitate the breeding and management of crops for enhanced productivity under B toxicity stress. [ABSTRACT FROM AUTHOR]

Compared to modifications at the molecular periphery, skeletal adjustments present greater challenges. Within this context, skeletal rearrangement technology stands out for its significant advantages in rapidly achieving structural diversity. Yet, the development of this technology for ring contraction of saturated cyclic amines remains exceedingly rare. While most existing methods rely on specific substitution patterns to achieve ring contraction, there is a persistent demand for a more general strategy for substitution‐free cyclic amines. To address this issue, we report a B(C6F5)3‐catalyzed skeletal rearrangement of hydroxylamines with hydrosilanes. This methodology, when combined with the N‐hydroxylation of amines, enables the regioselective ring contraction of cyclic amines and proves equally effective for rapid reorganization of acyclic amine skeletons. By this, the direct scaffold hopping of drug molecules and the strategic deletion of carbon atoms are achieved in a mild manner. Based on mechanistic experiments and density functional theory calculations, a possible mechanism for this process is proposed. [ABSTRACT FROM AUTHOR]

This manuscript describes a new strategy for prodrug synthesis in which a relatively inert ether group is introduced at an early stage in a synthetic sequence and functionalized in the final step to introduce a prodrug‐activating group through a chemoselective process. Boryl allyloxy (BAO) ether groups are synthesized through several metal‐mediated processes to form entities that are readily cleaved under oxidative conditions commonly found in cancer cells. The high cleavage propensity of the BAO group allows for ether cleavage, making these compounds substantially more hydrolytically stable in comparison to acyl‐linked prodrugs while retaining the ability to release alcohols. We report the preparation of prodrug analogues of the natural products camptothecin and pederin from acetal precursors that serve as protecting groups in their synthetic sequences. The BAO acetal groups cleave in the presence of hydrogen peroxide to release the cytotoxic agents. The pederin‐based prodrug shows dramatically greater cytotoxicity than negative controls and outstanding selectivity and potency toward cancer cell lines in comparison to non‐cancerous cell lines. This late‐stage functionalization approach to prodrug synthesis should be applicable to numerous systems that can be accessed through chemoselective processes. [ABSTRACT FROM AUTHOR]

Boron geochemistry from biogenic carbonates offer valuable information about ocean pH and CO2 chemistry. However, application to geological carbonate deposits suffers from analytical difficulties in obtaining geochemical signals exclusively from the carbonate phase. Sequential leaching with reagents and acids has the potential to overcome such an issue. There is, however, little systematic investigation about the efficiency of sequential leaching in isolating carbonate‐associated boron from siliciclastic matrix. Here, we developed a sequential leaching protocol and applied it to methane‐derived‐authigenic‐carbonate samples. Using the leachate δ11B signatures, elemental composition, and mineral composition of residues, we show that the sequential leaching is able to improve the separation of boron from different phases. Buffered hydrogen peroxide removes organic matter and also some silicate phases resulting low δ11B values. Leaching with NH4Ac removes adsorbed boron though may also partially leach some carbonate phases. The first few leaching steps with diluted acetic acid dissolve carbonate phases. Depending on the sample type, these may also capture some remaining adsorbed boron from the preceding NH4Ac leaching. Once the adsorbed boron is completely removed, as indicated by the progressively higher δ11B values during the following acid leaching steps, representative carbonate composition can be derived. The accuracy of this protocol is demonstrated with leaching experiments using artificial deep sea coral carbonate and clay mixtures that give the representative carbonate‐associated δ11B within error of the pure coral value. Our results provide insights into characteristic signatures derived from silicates and organic matter that need to be considered in boron isotope analyses of impure marine carbonates. Key Points: Boron signals from geological carbonate deposits are difficult to isolate from siliciclastic components of mixed matrix samplesA calibrated sequential leaching protocol was developed to extract boron from the carbonate phase of mixed carbonate‐silicate limestonesSuccessful separation is possible in samples with only 25% carbonate, provided the protocol is adjusted for carbonate content [ABSTRACT FROM AUTHOR]

In China, high copper (Cu) and low organic matter often occur in some citrus orchard soils. However, the underlying mechanisms by which humic acid (HA) stimulates growth and mitigates Cu toxicity of citrus seedlings are unclear. After being treated with 0, 0.1, or 0.5 mM sodium humate and 0.5 or 400 μM CuCl2 (Cu excess) for 24 weeks, sweet orange [Citrus sinensis (L.) Osbeck cv. Xuegan] seedlings were used to examine the impacts of HA-Cu interactions on seedling growth, nutrient uptake, leaf pigments, and photosynthetic performance that was revealed by chlorophyll a fluorescence transient. Copper excess reduced root, stem, and leaf dry weight (DW) by 42.4%, 65.4%, and 61.6%, respectively at 0 mM HA, and by 17.3%, 25.4%, and 31.4%, respectively at 0.5 mM HA; and that the levels of Cu in leaves, stems, and roots declined with elevating HA supply. Copper excess caused some rotten and dead fibrous roots at 0 mM HA, but not at 0.5 mM HA. Adding HA lowered Cu uptake per root DW (UPR), the levels of Cu in leaves, stems, and roots, and the competition of Cu2+ with Mg2+ and Fe2+, and therefore mitigated root impairment caused by Cu excess. The HA-mediated alleviation of root damage caused by Cu excess increased the uptake per plant and UPR of nitrogen, potassium, magnesium, phosphorus, calcium, sulfur, boron, and manganese, and therefore alleviated Cu excess-induced decline in seedling growth, impairment to leaf photosynthetic electron transport chains, and decrease in leaf pigments. For 0.5 μM Cu-treated seedlings, adding HA promoted seedling growth by improving root nutrient uptake and leaf photosynthetic performance. Cu excess aggravated the impacts of HA supplementation on seedling growth, leaf photosynthetic performance, and root nutrient uptake. [ABSTRACT FROM AUTHOR]

Rapeseed (Brassica napus L.) is a major oilseed crop with high boron (B) requirements. In hydroponic cultivation, B uptake is highly responsive to the media conditions (e.g., pH). Different N sources, such as NH4+ and NO3−, directly affect the media pH. To date, the underlying mechanisms, the role of the buffering at constant N-sources by separating the effects of pH and/or sources of N-form, for the uptake of B remain indistinct under hydroponic cultivation, particularly in rapeseed. Two identical experiments were conducted using (NH4)2SO4 and Ca(NO3)2 as sole N-sources each set were subjected to four treatments viz. non-buffered, buffered pH 5.0, 6.0, and 7.0 at low (1 µM) and high (100 µM) B for 5 days. The novelty of this study demonstrates that NH4+-fed plants prefer buffered pH (6 and 7) for promoting higher plant growth, which was in line with the B concentration, while NO3−-fed plants were not influenced. These aforesaid findings were further supported by the upregulation of BnaNIP5;1 and BnaBOR1;2 in the root and higher expression of BnaNIP5;1 in shoots with buffered pH in NH4+-fed plants. According to our findings, in NH4+-based buffering, B transport channel protein BnaNIP5;1 (through diffusion) facilitated B uptake and distribution from root to shoot while BnaBOR1;2 mediated active uptake of B was in root under low supply of B. In a nutshell, pH buffering in hydroponics is very important in NH4+-based but not in NO3−-based nutrition for the uptake of boron and growth of the rapeseed plants. [ABSTRACT FROM AUTHOR]

The 0106‐B1‐bioactive glass (BG) composition (in wt %: 37.5 SiO2, 22.6 CaO, 5.9 Na2O, 4.0 P2O5, 12.0 K2O, 5.5 MgO, and 12.5 B2O3) has demonstrated favorable processing properties and promising bone regeneration potential. The present study aimed to evaluate the biological effects of the incorporation of highly pro‐angiogenic copper (Cu) in 0106‐B1‐BG in vitro using human bone marrow‐derived mesenchymal stromal cells (BMSCs) as well as its in vivo potential for bone regeneration. CuO was added to 0106‐B1‐BG in exchange for CaO, resulting in Cu‐doped BG compositions containing 1.0, 2.5 and 5.0 wt % CuO (composition in wt %: 37.5 SiO2, 21.6/ 20.1/17.6 CaO, 5.9 Na2O, 4.0 P2O5, 12.0 K2O, 5.5 MgO, 12.5 B2O3, and 1.0/ 2.5/ 5.0 CuO). In vitro, the BGs' impact on the viability, proliferation, and growth patterns of BMSCs was evaluated. Analyses of protein secretion, matrix formation, and gene expression were used for the assessment of the BGs' influence on BMSCs regarding osteogenic differentiation and angiogenic stimulation. The presence of Cu improved cytocompatibility, osteogenic differentiation, and angiogenic response when compared with unmodified 0106‐B1‐BG in vitro. In vivo, a critical‐size femoral defect in rats was filled with scaffolds made from BGs. Bone regeneration was evaluated by micro‐computed tomography. Histological analysis was performed to assess bone maturation and angiogenesis. In vivo effects regarding defect closure, presence of osteoclastic cells or vascular structures in the defect were not significantly changed by the addition of Cu compared with undoped 0106‐B1‐BG scaffolds. Hence, while the in vitro properties of the 0106‐B1‐BG were significantly improved by the incorporation of Cu, further evaluation of the BG composition is necessary to transfer these effects to an in vivo setting. [ABSTRACT FROM AUTHOR]

The effect of boron doping on dielectric properties was examined using β-SrTa2O6:xEu3+ (x = 1.5 mol%, 3 mol%, 5 mol%, 10 mol%), β-SrTa2O6:xEu3+, yB3+ (x = 1.5 mol%, 3 mol%, 5 mol%, 10 mol%, y = 10 mol%) and BaTa2O6:xEu3+, yB3+ (x = 10 mol%, y = 0 mol%, 5 mol%, 15 mol%, 30 mol%, 50 mol%, 70 mol%, 100 mol%) tungsten bronze ceramics produced by the solid-state reaction method. X-ray diffraction (XRD) results of all the β-SrTa2O6 and BaTa2O6 samples showed that they retained a single-phase structure. In scanning electron microscopy (SEM) examinations, the presence of boron promoted grain growth and agglomeration in the β-SrTa2O6 grains, while the increased boron concentration led to grain elongation in addition to grain growth in the BaTa2O6 grains. The dielectric results for the β-SrTa2O6:xEu3+ and β-SrTa2O6:xEu3+, yB3+ series showed that increased Eu3+ caused a decrease in the dielectric constant (ε′) and dielectric loss (tan δ), whereas the increasing B3+ presence for the BaTa2O6:xEu3+, yB3+ series led to an increase in the dielectric constant and a decrease in dielectric loss. The increase in tetragonality for BaTa2O6:xEu3+, yB3+ ceramics was correlated with a higher ferroelectric Curie temperature. [ABSTRACT FROM AUTHOR]

Boron deficiency is a prevalent challenge for plant nutrition supply in many alkaline/calcareous soils. The current research aimed to examine the effects of boron supply to bell pepper plants through fertigation and foliar application. The experiment had seven treatments, comprising a control group, boric acid as fertigation (0.5, 1, and 2 g L-1), and foliar application (0.5, 1, and 2 g L-1) with three replications in controlled greenhouse conditions. The treatments were applied on Lorca bell peppers in a completely randomized design. The results showed that fertigation and foliar application increased all measured characteristics compared to the control group. Increasing the boric acid concentration in foliar application caused a decrease in fruit count per plant, fruit fresh weight, fruit yield per plant, and fruit width. Both fertigation and foliar boric acid applications at a low level (0.5 g L-1) and as separate treatments caused the highest fruit weight, length, width, and fruit count per plant. Higher boric acid concentrations increased chlorophyll a, b, total chlorophyll, leaf carotenoid content, soluble sugars, total soluble solids, titratable acidity, total phenols, and fruit ascorbic acid content. The highest chlorophyll a, b, total chlorophyll, leaf carotenoid content, and fruit ascorbic acid were observed in response to the high concentration of boric acid foliar application (2 g L-1). Overall, the boron supplement as a foliar application (0.5 to 1 g L-1) or fertigation (0.5 to 1 g L-1) improved quantitative and qualitative performance in bell peppers. [ABSTRACT FROM AUTHOR]

Electrofluorochromic (EFC) materials and devices with controllable fluorescence properties show great application potential in advanced anticounterfeiting, information storage and display. However, the low color purity caused by the broad emission spectra and underperforming switching time of the existing EFC materials limit their application. Through biomimetic exploration and the study of reversible electrochemical responsive coordination reactions, boron–nitrogen embedded polyaromatics (B,N‐PAHs) with narrow‐band emission and high color purity have been successfully integrated into EFC systems, which also help to better understand the role of boron in biological activity. The EFC device achieve good performance containing quenching efficiency greater than 90% within short switching time (ton: 0.6 s, toff: 2.4 s), and nearly no performance change after 200 cycles test. Three primary color (red, green, and blue) EFC devices are successfully prepared. In addition, new phenomena are obtained and discussed in this biomimetic exploration of related boron reactions. The success and harvest of this exploration are expected to provide new ideas for optimizing properties and broadening applications of EFC materials. Moreover, it may provide ideas and reference significance for further exploring and understanding the function of boron compounds in biological systems. [ABSTRACT FROM AUTHOR]

Using the structure-induced effect of KBH(mim)3 ligand, four 2-dimensional (2D) boron imidazolate frameworks with identical body framework and different dangling monocarboxylate ligands, have been synthesized. Electrocatalytic results indicate that the surrounding microenvironment regulation could effectively affect the activity and selectivity towards C2H4. BIF-151 showed the highest electrocatalytic performances with the Faraday efficiency (FE) of 25.94% for C2H4 at −1.4 V vs. RHE. [ABSTRACT FROM AUTHOR]

Boric acid and other impurities on the surface of boron (B) particles can interact with hydroxyl-terminated polybutadiene (HTPB), weakening the mechanical properties and energy release efficiency of boron-based solid rocket propellants. SA@B composite particles were created by coating stearic acid (SA) on the surface of B particles through solvent evaporation-induced self-assembly. The study investigated the impact of SA coating on the combustion performance of B particles and the mechanical properties of HTPB matrix composites. The results showed that the SA coating enhanced the oxidation efficiency of B particles in air. The combustion heat of SA@B composite particles is 30.29 MJ/g, about 50% higher than that of B particles. During the combustion of SA@B composite particles, fewer molten solid particles surround the flame, which enhances the stability of the combustion process of the B particles. Furthermore, the SA coating effectively enhanced the dispersion of B particles in HTPB. At a stretching speed of 100 mm/min, the tensile strength of the SA@B/HTPB composite materials is higher than that of the B/HTPB composite materials. Moreover, when the mass loading of the SA@B composite particles reaches 50 wt%, the tensile strength of SA@B/HTPB composite materials is 2.46 MPa. Activating the surface of boron particles with SA can significantly improve their compatibility with HTPB, which is crucial for the stable storage of boron-based solid rocket propellants. [ABSTRACT FROM AUTHOR]

Diamond films possess numerous extraordinary physical and chemical properties, but their high-temperature applications are limited by its poor thermal stability. Herein, we fabricated the undoped microcrystalline diamond (MCD) film and heavy boron-doped diamond (h-BDD-1, 2.94 × 1021 atoms·cm−3; h-BDD-2, 9.10 × 1021 atoms·cm−3) films to investigate the effect of boron doping on the thermal stability of diamond films. A series of evidences, including air annealing experiments, thermogravimetric-differential scanning calorimetry (TG-DSC) analysis, and in-situ ultra-high-temperature confocal laser-scanning microscope (CLSM), demonstrated that the thermal stability of diamond films was obviously enhanced by boron doping. Consequently, the h-BDD-2 film exhibited the best thermal stability with an initial oxidation temperature above 900 °C, which was much higher than that of MCD film (709 °C). By deconvolving the X-ray photoelectron spectra, we believed that the transition of B–C bonds to stable oxy-boron carbide complexes (B 4 O–C, B 3 O–C) is the key to improving the thermal stability. These results not only reveal a new antioxidant mechanism of boron-doped diamond films but also pave a way for the application of diamond in high-temperature environments. [ABSTRACT FROM AUTHOR]

The synthesis of strained carbocyclic building blocks is relevant for Medicinal Chemistry, and methylenecyclobutanes are particularly challenging with current synthetic technology. Careful inspection of the reactivity of [1.1.1]propellane and diboron reagents has revealed that bis(catecholato)diboron (B2cat2) can produce a bis(borylated) methylenecyclobutane in a few minutes at room temperature. This reaction constitutes the first example of B−B bond activation by a special apolar hydrocarbon and also the first time that propellane is electrophilically activated by boron. Mechanistic studies including in situ NMR kinetics and DFT calculations demonstrate that the diboron moiety can be directly activated through coordination with the inverted sigma bond of propellane, and reveal that DMF is involved in the stabilization of diboronate ylide intermediates rather than the activation of the B−B bond. These results enable new possibilities for both diboron and propellane chemistry, and for further developments in the synthesis of methylenecyclobutanes based on propellane strain release. [ABSTRACT FROM AUTHOR]

Piperidines are widely present in small molecule drugs and natural products. Despite many methods have been developed for their synthesis, new approaches to polysubstituted piperidines are highly desirable. This work presents a radical (4+2) cycloaddition reaction for synthesis of piperidines featuring dense substituents at 3,4,5‐positions that are not readily accessible by known methods. Using commercially available diboron(4) compounds and 4‐phenylpyridine as the catalyst precursors, the boronyl radical‐catalyzed cycloaddition between 3‐aroyl azetidines and various alkenes, including previously unreactive 1,2‐di‐, tri‐, and tetrasubstituted alkenes, has delivered the polysubstituted piperidines in generally high yield and diastereoselectivity. The reaction also features high modularity, atom economy, broad substrate scope, metal‐free conditions, simple catalysts and operation. The utilization of the products has been demonstrated by selective transformations. A plausible mechanism, with the ring‐opening of azetidine as the rate‐limiting step, has been proposed based on the experimental and computational results. [ABSTRACT FROM AUTHOR]

Boron- B is an essential element for the growth and development of plants. Its deficiency in hot, dry areas with calcareous soils can significantly reduce agricultural crop production. To study the impact of B fertilization, an experiment was conducted using a completely randomized design with seven treatments, including control, foliar spray (0.5, 1, and 2 g L−1 boric acid), and fertigation (0.5, 1, and 2 g L−1 boric acid). The experiment, with three replicates, was carried out in greenhouse conditions on pepper plants (Capsicum annuum cv. Lorca). The highest fruit yield was achieved with foliar spray at a concentration of 0.5 g L−1 and fertigation at 1 g L−1. Overall, the use of B fertilizer increased the concentration of macronutrients such as potassium-K (up to 27.79%), phosphorus-P (up to 59%), calcium-Ca (up to 49.61%), and magnesium-Mg (up to 158%), as well as micronutrients like iron-Fe (up to 59.55%), manganese-Mn (up to 29.03%), zinc-Zn (up to 81.81%), copper-Cu (up to 49.33%), B (up to 180%), and sodium-Na (up to 85.19%). It also decreased the concentration of nitrogen-N (up to 15%), sulfur-S (up to 21.36%), and chlorine-Cl (up to 48.02%) in the leaf tissue of pepper plants compared to the control treatment. These changes were influenced by the B concentration and type of fertilization. The results indicate that in calcareous soils with high pH, both fertigation and foliar spray methods can effectively address B deficiency in pepper plants by enhancing element absorption and increasing yield. [ABSTRACT FROM AUTHOR]

Boron doped MoSi 2 particles have been envisioned as sacrificial particles for self-healing thermal barrier coatings (TBCs) but their oxidation behaviour is yet not well understood. In this work, oxidation of MoSi 2 based particle is studied in the temperature range of 1050–1200 °C. The oxidation proceeds from a transient to a steady-state oxidation stage. The kinetics during steady-state oxidation is captured with a thermal diffusion-based model. As compared to the oxidation of pure MoSi 2 particles, the addition of boron strongly enhances the silica formation. Also, a finer dispersion of MoB x in the MoSi 2 matrix accelerates the formation of silica. The oxide growth rate constant increases proportional with the boron content of the MoSi 2 particles. This enhanced oxidation is related to the microstructure of the oxide scale. Upon oxidation, boron yields B 2 O 3 , which promptly merge with SiO 2 to form amorphous borosilicate, hindering the formation of crystalline SiO 2. Consequently, the migration of oxygen in the borosilicate oxide scale is faster than in the silica oxide scale on pure MoSi 2 particles. [ABSTRACT FROM AUTHOR]

Commercially available bioactive glasses (BAGs) are exclusively used in powder form, due to their tendency to crystallize. Silicate BAG 1393 was developed to allow fiber drawing and scaffold sintering, but its slow degradation limits its potential. To enable scaffold manufacturing while maintaining glass dissolution rate close to that of commercially available BAGs, the borosilicate glass 1393B20 was developed. This study investigates the potential of 1393B20 scaffolds to support bone regeneration and mineralization in vitro and in vivo , in comparison to silicate 1393. Both scaffolds supported human adipose stem cells proliferation, either in direct contact for the 1393, or mainly around for the 1393B20. Similarly, both BAGs induced osteogenesis and angiogenesis in vitro , with a better pro-angiogenic influence of the 1393B20. In addition, these scaffolds supported bone regeneration and osteoclast/osteoblast activity in vivo in critical-sized rat calvarial defect. Nevertheless, mineralization and collagen formation were significantly enhanced for the 1393B20, at 3-months post-implantation, assigned to faster and more complete dissolution of the scaffolds. Thus, 1393B20 demonstrates greater promise for bone tissue engineering certainly due to its time-controlled release of boron and silicon. Bioactive glasses (BAGs) show great promise in bone tissue engineering as they effectively bond with bone tissue, fostering integration and regeneration. Silicate BAG 1393 was developed to allow fiber drawing and scaffold sintering, but its slow degradation limits its potential. To enable scaffold manufacturing while maintaining glass dissolution rate close to that of commercially available BAGs, the borosilicate glass 1393B20 was developed. Both BAGs induced osteogenesis and angiogenesis in vitro , with a better pro-angiogenic influence of the 1393B20. The presence of boron in the 1393B20 enhanced mineralization and collagen formation in vivo compared to 1393, probably due to its faster dissolution rate. Here, 1393B20 demonstrated greater promise for bone tissue engineering compared to the well-known 1393 BAG. [Display omitted] [ABSTRACT FROM AUTHOR]

A series of boron difluoro bis(diiminate) complexes have been prepared and used to obtain triflate substituted fluoroborane complexes. The corresponding well-defined bis(borenium) cations were subsequently synthesized and structurally authenticated. We are also presenting the first experimental and theoretical study of bis(borenium) cations that are derivative of cationic borinic acid. [ABSTRACT FROM AUTHOR]