Boron-containing Species Research Articles

Comprehensive analysis of boron-induced modification in LiNi0.8Mn0.1Co0.1O2 positive electrode material for lithium-ion batteries

Ni-rich layered oxides (Ni-rich NMCs) are attractive cathodes for LIBs demonstrating remarkable specific capacity. Still, their commercial deployment is hindered by insufficient cycle life. To address this issue, both doping with boron and coating with boron-containing species are known to work effectively, however, the exact nature of stability improvement along with the precise effect of boron on the crystal structure and morphology of Ni-rich NMCs are not comprehensively understood. Herein, we scrutinized B-modified LiNi0.8Mn0.1Co0.1O2 (NMC811) with a combination of bulk and local experimental techniques supported with DFT calculations, both of which exclude insertion of boron into the crystal lattice of NMC811 and indicate that it is present as Li3BO3. We have visualized ∼2 nm Li3BO3 coating at the surface of NMC811 primary particles using electron-energy loss spectroscopy. This coating induces plate-shaped morphology of the primary particles instead of suggested earlier rod- and needle-like shapes and provides enhancement of capacity retention mainly due to improved reversibility of the H2→H3 phase transition upon charge/discharge. This study covers a plethora of boron modification aspects that have remained unclear or controversial so far, eliminating common misconceptions and contributing to understanding of boron impact on the electrochemical properties of Ni-rich NMCs.

Story of Hydroboration: Experimentally Generated Mechanistic Insights

Reduction of various unsaturated organic substrates via hydroboration represents one of the most commonly used procedures. Nevertheless, controversial information about the mechanistic insights regarding this particular transformation still exists in the literature. In this work, we show that three-coordinate mono-aminoboranes do not act as effective hydroboration reagents as recently reported unless these boron-containing species are able to form four-coordinate analogues either through dimerization or addition of a base. Furthermore, we also demonstrate that imine-BH3 adduct(s) and mono-amino boranes do not represent key intermediates during Me2S-BH3 catalyzed hydroboration of imines using HBpin as recently reported. In fact, we believe that in both of these reported studies, the Clark mechanism is mainly, if not solely, responsible for the observed/examined hydroboration reactions.

Trimetallic Chalcogenide Species: Synthesis, Structures, and Bonding.

In an attempt to isolate boron-containing tri-niobium polychalcogenide species, we have carried out prolonged thermolysis reactions of [Cp*NbCl4] (Cp* = ɳ5-C5Me5) with four equivalents of Li[BH2E3] (E = Se or S). In the case of the heavier chalcogen (Se), the reaction led to the isolation of the tri-niobium cubane-like cluster [(NbCp*)3(μ3-Se)3(BH)(μ-Se)3] (1) and the homocubane-like cluster [(NbCp*)3(μ3-Se)3(μ-Se)3(BH)(μ-Se)] (2). Interestingly, the tri-niobium framework of 1 stabilizes a selenaborate {Se3BH}- ligand. A selenium atom is further introduced between boron and one of the selenium atoms of 1 to yield cluster 2. On the other hand, the reaction with the sulfur-containing borate adduct [LiBH2S3] afforded the trimetallic clusters [(NbCp*)3(μ-S)4{μ-S2(BH)}] (3) and [(NbCp*)3(μ-S)4{μ-S2(S)}] (4). Both clusters 3 and 4 have an Nb3S6 core, which further stabilizes {BH} and mono-sulfur units, respectively, through bi-chalcogen coordination. All of these species were characterized by 11B{1H}, 1H, and 13C{1H} NMR spectroscopy, mass spectrometry, infrared (IR) spectroscopy, and single-crystal X-ray crystallography. Moreover, theoretical investigations revealed that the triangular Nb3 framework is aromatic in nature and plays a vital role in the stabilization of the borate, borane, and chalcogen units.

Selective oxidation of methane to CO on Ni@BOx via reaction-induced vapor migration of boron-containing species onto Ni

Dynamic migration of support-derived species and subsequent encapsulation of supported metal nanoparticles (NPs) are the well-known features of the Strong Metal-Support Interaction (SMSI) effect. Here, we report occurrence of the classical SMSI state in physical mixture of Ni NPs and porous hexagonal boron nitride powder (Ni|pBN) during methane oxidation reaction at 600 ℃, in which Ni NPs are encapsulated by BOx overlayers derived from the pBN component. The SMSI state can switch the methane oxidation selectivity from CO2 on the fresh Ni|pBN catalyst to CO on the used catalyst. The encapsulation of Ni NPs by BOx overlayers has also been observed in Ni/Al2O3 catalyst which is physically mixed with pBN. Comprehensive characterizations confirm that the SMSI state is induced by vapor migration of boron-containing species e.g. BOxHy from pBN to metal surfaces, in which both high reaction temperature and water product play an important role.

Solubility Isotherm Determinations at T = (273.15, 298.15, 323.15, 348.15 and 363.15) K and Thermodynamic Modeling of the H3BO3 + SrCl2 + H2O System

Boron abundantly exists in salt lake brine system as various boron-containing aqueous species or minerals. The phase behavior of boron and other substances (Li, Na, K, Rb, Cs, Mg, Ca, Sr, Cl, S etc.) in the complicated salt brine system during the solar pool process needs to be simulated and predicted by models. Basic experimental data (e.g. solubility, etc.) of simple binary and ternary system are necessary for the model parameterizations. At present, the unavailability of solubility data in the H3BO3 + SrCl2 + H2O ternary system makes the model parameterization difficult. In this paper, we determined the solubility isotherms in the H3BO3 + SrCl2 + H2O ternary system at 273.15 K, 298.15 K, 323.15 K, 348.15 K and 363.15 K. The result show that the isotherms all consisted of the solubility branches H3BO3(cr) and SrCl2⋅nH2O(cr) (n = 6 and 2), and no new phase has been found. Then, a Pitzer–Simonson–Clegg (PSC) model in the ISLEC software package was used to simulate the thermodynamic properties of the H3BO3 + H2O, SrCl2 + H2O, and H3BO3 + SrCl2 + H2O systems, including solubility, water activity, activity coefficients, heat capacity and enthalpy of dilution. With the obtained model parameters, a complete polythermal phase diagram of the H3BO3 + SrCl2 + H2O system was predicted at temperatures from 255 to 373 K. The present work lays the foundation for the future simulations of complicated salt lake brine systems containing H3BO3 and SrCl2.

Nonclassical cooperative mechanism in Suzuki-Miyaura reaction – Is it possible?

Herein, the independent differential selectivity in the Suzuki-Miyaura reaction of two competing arylboronic acids with regard to the nature of the aryl halide (both halide and aryl moieties) was established. This pattern cannot be realized via the “textbook” mechanism of the reaction, which suggests the interaction of boron-containing species with an ArPdX intermediate (product of the aryl halide catalytic activation). The data obtained indicate the participation of two distinct palladium species in the aryl halide and arylboronic acid activations in the catalytic cycle of biaryl formation, which are in accordance with the so-called cooperative mechanism.

Photoelectron spectroscopy of boron-containing reactive intermediates using synchrotron radiation: BH2, BH, and BF.

Mass selected slow photoelectron spectra (SPES) of three boron-containing reactive species, BH2, BH, and BF were recorded by double imaging photoion-photoelectron coincidence spectroscopy (i2PEPICO) using synchrotron radiation. All species were generated in a flow reactor from the H-abstraction of B2H6 by F atoms created in a F2 microwave discharge. The spectrum of BH2+ exhibits a long bending mode progression with a 970 cm-1 spacing due to the large geometry change from bent to linear upon ionization. Its ionization energy was determined as 8.12 ± 0.02 eV. For BH, photoionisation from both X1Σ+ singlet and a3Π triplet state was observed, permitting the experimental determination of the singlet/triplet gap (ΔEST) from the observed IE's of 9.82 eV and 8.48 eV. In addition, a threshold photoelectron spectrum of BF was recorded, which leads to an IE of 11.11 eV and an improved value for νBF+ of 1690 cm-1. All spectra were simulated by calculating Franck-Condon factors from optimised structures based on quantum chemical calculations.

Substitution of the laser borane anti-B18H22 with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides.

Reaction of anti-B18H221 with pyridine in neutral solvents gives sparingly soluble B16H18-3',8'-Py23a as the major product (ca. 53%) and B18H20-6',9'-Py22 (ca. 15%) as the minor product, with small quantities of B18H20-8'-Py 4 (ca. 1%) also being formed. The three new compounds 2, 3a and 4 are characterized by single-crystal X-ray diffraction analyses and by multinuclear multiple-resonance NMR spectroscopy. Compound 2 is of ten-vertex nido:ten-vertex arachno two-atoms-in-common architecture, long postulated for a species with borons-only cluster constitution, but previously elusive. Compound 3a is of unprecedented ten-vertex nido:eight-vertex arachno two-atoms-in-common architecture. The single-crystal X-ray diffraction analysis for the picoline derivative B16H18(NC5H4Me)23b, similarly obtained, is also presented. B18H20Py 4 is also previously unreported but is of known ten-vertex nido:ten-vertex nido two-atoms-in-common architecture of anti configuration, but now with the pyridine ligand positioned differently to other reported examples of B18H20L compounds. Factors behind the remarkably low solubility of 3a and 3b are elucidated in terms of electrostatic potential (ESP) calculations, polarity, and van der Waals complementarities. In view of contemporary developing high interest in the fluorescent properties of macropolyhedral boron-containing species, a detailed assessment of the photophysical characteristics of 3a and 4 is also presented. In contrast to the thermochromic fluorescence of 2 (from 620 nm brick-red at room temperature to 585 nm yellow at 8 K, quantum yield 0.15), compound 3a is only weakly phosphorescent in the yellow region (590 nm, quantum yield 0.01), whereas compound 4 exhibits no luminescence. The far more photoactive nature of compound 2 is associated with S1 excited-state minima structures that differ from each other only by the relative rotational positions of the pyridine substituents on its disubstituted ten-vertex {arachno-B10Py2}-subcluster. The wavelength and relative intensity of fluorescence from these structures depends on the rotational positions of the pyridine ligands, which in turn are influenced by temperature and/or rotational inhibition in the solid-state.

Raman Spectroscopic and ab Initio Investigation of Aqueous Boric Acid, Borate, and Polyborate Speciation from 25 to 80 °C

Temperature-dependent Raman studies of the aqueous speciation of boric acid and sodium borate have been carried out at 25 and 80 °C. Normalized solvent-corrected reduced isotropic Raman spectra were obtained from perpendicular and parallel polarization measurements using perchlorate anion, [ClO4]−, as an internal standard. The intensity variations of these bands with concentration and temperature provided strong evidence that these arise from boric acid B(OH)3, borate [B(OH)4]−, and the polyborate species [B3O3(OH)4]−, [B4O5(OH)4]2–, and [B5O6(OH)4]−. A very weak high frequency shoulder on the borate band may indicate the presence of the diborate species [B2O(OH)5]−. Temperature- and concentration-independent quantitative Raman molar scattering coefficients (S) for the symmetric vibrational bands of boron-containing species were calculated, consistent with the mixed solvent electrolyte model reported by Wang et al. (Pure Appl. Chem. 2013, 85, 2117–2144) up to approximately 100 °C. The band assignments and...

Synergistic effect between organic borate esters and phosphorus-based additives on tribological performances as lubricant additives in mineral oil

Nowadays, looking for environment-friendly lubricant additives to replace phosphorus-based derivatives in automotive lubricating system is one of the main objectives. Organic borate ester is one kind of potential substitutes for phosphorus-based derivatives. In this paper, the interactions of organic borate esters and dioctylphosphite ester on tribological performances were studied. Results showed that they had a synergistic effect on antiwear performance and friction-reducing property as lubricant additives in mineral oil. The chemical nature of worn surface was explored by X-ray absorption near-edge structure spectroscopy. Borate ester could facilitate the decomposition of phosphorus-based additive and the formation of phosphate. What is more, boron-containing species could react with phosphate to form boron–phosphorus-based thin film on the surface. Boron mainly forms B2O3 on the surface. In the near surface of tribofilm, nitrogen-containing borate ester reduced the polyphosphate chain length due to the formation of ammonium cation. The polyphosphate chain length of the tribofilm generated from dioctylphosphite ester mixed with nitrogen-containing alkyl borate ester is shorter compared to that of the tribofilm generated from dioctylphosphite ester mixed with nitrogen-containing heterocyclic borate ester.

Carbon Nanotubes as Support in the Platinum‐Catalyzed Hydrolytic Dehydrogenation of Ammonia Borane

We report remarkable support effects for carbon nanotubes (CNTs) in the Pt/CNT-catalyzed hydrolytic dehydrogenation of ammonia borane. The origin of the support-dependent activity and durability is elucidated by combining the catalytic and durability testing with characterization by a range of spectroscopy and high-angle annular dark-field scanning transmission electron microscopy techniques and ICP analysis. The effects mainly arise from different electronic properties and different abilities for the adsorption of boron-containing species on platinum surfaces and changes in size and shape of the platinum particles during the reaction. Defect-rich CNTs in particular are a promising support material, as it not only enhances the platinum binding energy, leading to the highest hydrogen generation rate, but also inhibits the adsorption of boron-containing species and stabilizes the platinum nanoparticles to resist the agglomeration during the reaction, leading to the highest durability. The insights revealed herein may pave the way for the rational design of highly active and durable metal/carbon catalysts for the hydrolytic dehydrogenation of ammonia borane.

Low temperature boron doping into crystalline silicon by boron-containing species generated in Cat-CVD apparatus

We have discovered that phosphorus (P) atoms can be doped into crystalline silicon (c-Si) at temperatures below 350°C or even at 80°C by using species generated by catalytic cracking reaction of phosphine (PH3) molecules with heated tungsten (W) catalyzer in Cat-CVD apparatus. As further investigation, here, we study the feasibility of low temperature doping of boron (B) atoms into c-Si by using decomposed species generated similarly from diborane (B2H6) molecules. Dependency of properties of doped layers on catalyzer temperature (Tcat) and substrate temperature (Ts) is studied by both the Van der Pauw method based on the Hall-effect measurements and secondary ion mass spectroscopy (SIMS) for B doping in addition to P doping. It is found that, similarly to P doping, the surface of n-type c-Si is converted to p-type even at Ts=80°C for Tcat over 800°C when c-Si is exposed to B2H6 cracked species for a few minutes, and that the heat of substrate over 300°C is likely to help for B doping contrary to P doping.

Characterization of Fast Pyrolysis Products Generated from Several Western USA Woody Species

Woody biomass has the potential to be utilized at an alternative fuel source through its pyrolytic conversion. Here, fast pyrolysis bio-oils derived from several western USA woody species are characterized by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) to determine molecular-level composition. The composition and properties (pH, electrical conductivity, and elemental analyses) of the biochar byproduct were also determined. The bio-oils are comprised mainly of Ox species. Oak (Quercus garryana Douglas ex Hook), mixed conifer (Pseudotsuga menziesii Mirb. Franco, Tsuga heterophylla (Raf.) Sarg, Abies concolor (Gord. & Glend.) Lindl. ex Hildebr.), and scotch broom (Cytisus scoparius (L.) Link) bio-oils contain lower Ox (O1–O7) species that exhibit bimodal distributions whereas mixed conifer feedstock from a fire salvage harvest contains a larger range of Ox species (O2–O13) that exhibit a mainly monomodal distribution. Boron-containing species in the pyrolysis oils were also identified for the first time by FT-ICR MS. Biochar analysis revealed that all biochars had similar pH values (∼7–8); however, the electrical conductivity and elemental analyses varied across the samples. Understanding the composition of pyrolysis byproducts will help direct their uses to the most appropriate locations.

Insights into the Electrochemistry of the Deposition of Boron from KCl-KF-NaBF4 Melt

Electrochemical reduction of boron from boron containing fluoroborate species present in KCl (81.54 mol%)-KF (18.45 mol%)-NaBF 4 (1.67x10 -4 mol cm -4 ) melt on a platinum electrode was studied by cyclic voltammetry and chronoamperometry. These studies were carried out over the temperature range 1073 – 1123 K. Boron-containing electroactive species is shown to reduce quasi-reversibly at low scan rates ( � 0.1 V s -1 ) through a single-step three-electron

Chemical fingerprinting of naphthenic acids and oil sands process waters—A review of analytical methods for environmental samples

This article provides a review of the routine methods currently utilized for total naphthenic acid analyses. There is a growing need to develop chemical methods that can selectively distinguish compounds found within industrially derived oil sands process affected waters (OSPW) from those derived from the natural weathering of oil sands deposits. Attention is thus given to the characterization of other OSPW components such as oil sands polar organic compounds, PAHs, and heavy metals along with characterization of chemical additives such as polyacrylamide polymers and trace levels of boron species. Environmental samples discussed cover the following matrices: OSPW containments, on-lease interceptor well systems, on- and off-lease groundwater, and river and lake surface waters. There are diverse ranges of methods available for analyses of total naphthenic acids. However, there is a need for inter-laboratory studies to compare their accuracy and precision for routine analyses. Recent advances in high- and medium-resolution mass spectrometry, concomitant with comprehensive mass spectrometry techniques following multi-dimensional chromatography or ion-mobility separations, have allowed for the speciation of monocarboxylic naphthenic acids along with a wide range of other species including humics. The distributions of oil sands polar organic compounds, particularly the sulphur containing species (i.e., OxS and OxS2) may allow for distinguishing sources of OSPW. The ratios of oxygen- (i.e., Ox) and nitrogen-containing species (i.e., NOx, and N2Ox) are useful for differentiating organic components derived from OSPW from natural components found within receiving waters. Synchronous fluorescence spectroscopy also provides a powerful screening technique capable of quickly detecting the presence of aromatic organic acids contained within oil sands naphthenic acid mixtures. Synchronous fluorescence spectroscopy provides diagnostic profiles for OSPW and potentially impacted groundwater that can be compared against reference groundwater and surface water samples. Novel applications of X-ray absorption near edge spectroscopy (XANES) are emerging for speciation of sulphur-containing species (both organic and inorganic components) as well as industrially derived boron-containing species. There is strong potential for an environmental forensics application of XANES for chemical fingerprinting of weathered sulphur-containing species and industrial additives in OSPW.

Enhanced Growth of Diamond Grains in Ultrananocrystalline Diamond/Hydrogenated Amorphous Carbon Composite Films by Pulsed Laser Deposition with Boron-Blended Graphite Targets

Ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon composite films were prepared by pulsed laser deposition with boron-blended graphite targets and the effects of the boron-doping on the growth of UNCD grains were investigated. With an increase in the boron content, the grain size was increased from 5 to 23 nm accompanied by the lattice constant approaching that of bulk diamond. The sp3/(sp3+ sp2) ratio estimated from the X-ray photoemission spectra was enhanced by the boron-doping, which might be predominantly attributable to the enlarged grains. The near-edge X-ray absorption fine-structure spectroscopic measurement revealed that boron atoms are preferentially distributed into grain boundaries. On the basis of the results, the roles of the boron atoms in the enhanced crystalline growth are discussed. We consider that the crystalline growth posterior to the nucleation is facilitated by boron atoms neighboring UNCD grains or by boron-containing energetic species in plasma.

Roles of boron in growth of diamond grains in ultrananocrystalline diamond/hydrogenated amorphous carbon composite films prepared by pulsed laser deposition

ABSTRACTBoron doped ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon composite films prepared by pulsed laser deposition were structurally investigated. With an increase in the boron content, the grain size was increased from 5 to 23 nm accompanying by the lattice constant approaching to that of bulk diamond. The near-edge X-ray absorption fine-structure revealed that boron atoms are preferentially distributed into grain boundaries. On the basis of the results, the roles of the boron atoms in the enhanced crystalline growth are discussed. We consider that the crystalline growth posterior to the nucleation is facilitated by boron atoms existing neighbor to UNCD grains or by boron-containing energetic species in plasma.

Characteristics and mechanisms of accelerating pack boriding by direct current field at low and moderate temperatures

Direct current field (DCF) was employed in pack boriding at low and moderate temperatures. Samples were arranged in different positions in a sealed pack boriding container for studying characteristics of the DCF assisted pack boriding and mechanisms of accelerating pack boriding by DCF. The test results revealed that DCF enhanced pack boriding not only to samples as cathode but also to samples located between the cathode and anode. The extent of the enhancement varied with the location of the sample. The strongest enhancement was achieved on the cathode sample's side facing the anode. It is proposed that the DCF's physical effect of enhancing chemical reactions in the agent increases the activity and productivity of boron-containing species. The DCF makes the concentrations of active boron-containing species at and around the sample as cathode much higher than in any other position by forcing boron-containing species to diffuse fast toward the cathode. The electrically induced boron migration in the sample by DCF leads a faster growth of boriding case at the sample's side facing the anode. The DCF's electromagnetic effect might be helpful for forming more vacancies in the sample, which favors boron's diffusion in the substrate.

Alkoxide-Catalyzed Reduction of Ketones with Pinacolborane

The reduction of ketones with pinacolborane (4,4,5,5-tetramethyl-1,3,2-dioxaborolane) is catalyzed by 5 mol % NaOt-Bu at ambient temperature. The reaction is high yielding and general, providing complete conversion of aryl and dialkyl ketones. Although spectroscopic studies of the active hydride source in benzene-d(6) were complicated due to poor solubility, the data are consistent with the active hydride source being the trialkoxyborohydride, which is believed to be present in low concentration under the reaction conditions. Performing analogous studies in tetrahydrofuran resulted in a complex equilibrium between several different boron-containing species in which the trialkoxyborohydride compound was the major species.

Transmetalation of Unsaturated Carbon Nucleophiles from Boron-Containing Species to the Mid to Late d-Block Metals of Relevance to Catalytic C−X Coupling Reactions (X = C, F, N, O, Pb, S, Se, Te)

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTTransmetalation of Unsaturated Carbon Nucleophiles from Boron-Containing Species to the Mid to Late d-Block Metals of Relevance to Catalytic C−X Coupling Reactions (X = C, F, N, O, Pb, S, Se, Te)David V. Partyka*View Author Information Creative Chemistry LLC, 2074 Adelbert Road, Cleveland, Ohio 44106, United States*E-mail: [email protected]. Phone: (216) 392 1772.Cite this: Chem. Rev. 2011, 111, 3, 1529–1595Publication Date (Web):March 9, 2011Publication History Received19 July 2010Published online9 March 2011Published inissue 9 March 2011https://doi.org/10.1021/cr1002276Copyright © 2011 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views11602Altmetric-Citations250LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (10 MB) Get e-AlertsSUBJECTS:Chemical reactions,Cross coupling reaction,Ligands,Metals,Transmetalation Get e-Alerts