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Raw material is one of the most decisive factors for the quality of sintered boron carbide (B4C) products, in the past, there were relatively successful efforts for the synthesis of B4C powders via carbothermal reduction approaches. To prepare high-quality powder, a deeper understanding of the relationship between technological manufacturing parameters and resulting powder properties is required. In this paper, pure B4C powders were synthesized by rapid carbothermal reduction (RCR) under B2O3 excess conditions using boric acid and a carbonizing binder as B2O3 and carbon source, respectively. The molar ratio of B2O3/C of starting mixtures was varied from 0.75:1 to 4:1. The effects of heat-treating temperature and starting composition on phase constitution, morphology as well as stoichiometry of the prepared powders were investigated. The studies show that the starting composition has no effect on the stoichiometry of the powders, all boron carbides synthesized at 1900 °C have a stoichiometric composition of B4C. With increasing heating temperature and B2O3 content in the starting composition, the particle size of B4C was reduced. Uniform B4C powders with an average grain size of 300 nm were synthesized at 1900 °C from a starting powder mixture with a molar ratio of B2O3/C = 4. A formation mechanism is proposed under large B2O3 excess conditions. For the starting powder mixtures with a molar ratio of B2O3/C < 2, the formation of boron carbide occurs through both liquid–solid reaction and gas–solid reaction. Accordingly, the synthesized powders exhibit a morphology with mixed elongated platelets and small polyhedral particles. For the starting powder mixtures with a molar ratio of B2O3/C ≥ 2, fine-sized B4C particles were formed by a liquid–solid reaction. [ABSTRACT FROM AUTHOR]

So far, no boron fullerenes were synthesized: more compact sp3-bonded clusters are energetically preferred. To circumvent this, metallic clusters have been suggested by Pochet et al. [Phys. Rev. B 83, 081403(R) (2011)] as 'seeds' for a possible synthesis which would topologically protect the sp2 sector of the configuration space. In this paper, we identify a basic pentagonal unit which allows a balance between the release of strain and the self-doping rule. We formulate a guiding principle for the stability of boron fullerenes, which takes the form of an isolated filled pentagon rule (IFPR). The role of metallic clusters is then reexamined. It is shown that the interplay of the IFPR and the seed-induced doping breaks polymorphism and its related problems: it can effectively select between different isomers and reduce the reactivity of the boron shells. The balance between self and exterior doping represents the best strategy for boron buckyball synthesis. [ABSTRACT FROM AUTHOR]

Purpose: To define the actions of boron on normal neurophysiology and glioblastoma growth. Materials and Methods: PubMed and other relevant databases were searched. Results: Discovery of novel boron compounds in treatment of glioblastoma is being actively investigated, but the majority of such studies is focused on the synthesis of boron compounds as sensitizers to Boron Neutron Capture Therapy (BNCT). Nonetheless, the translational functionality of boron compounds is not limited to BNCT as many boron compounds possess direct tumoricidal activity and there is substantial evidence that certain boron compounds can cross the blood-brain barrier. Moreover, boron-containing compounds interfere with several tumorigenic pathways including intratumoral IGF-I levels, molybdenum Fe–S containing flavin hydroxylases, glycolysis, Transient Receptor Potential (TRP) and Store Operated Calcium Entry (SOCE) channels. Conclusions: Boron compounds deserve to be studied further in treatment of systemic cancers and glioblastoma due to their versatile antineoplastic functions. [ABSTRACT FROM AUTHOR]

Cyanoborate chemistry has emerged to an important topic during the last two decades, beginning with two independent reports on the successful synthesis of the tetracyanoborate anion [B(CN)4]– in 2000. A wealth of cyanoborate anions with different substituents in addition to CN group(s) bonded to boron, i.e. hydrogen, halogen, aryl, alkenyl, alkyl, perfluoroalkyl, and alkoxy, have been developed, which enable the tuning of properties of compounds and materials based on them. The readily accessible alkali metal cyanoborates are convenient starting materials for the preparation of cyanoborates with various organic, inorganic, and metal cations as well as cyanoborate coordination compounds. A focus has been on low‐viscosity room temperature cyanoborate‐ionic liquids that are of interest for various applications, especially for electrochemical devices such as dye sensitized solar cells (DSSC) and supercapacitors. Many other potential applications of these novel substances in chemistry and materials science have been studied. Furthermore, cyanoborates are promising starting compounds for the synthesis of other boron species, for example the weakly coordinating tetrakis(trifluoromethyl)borate anion [B(CF3)4]– and the boron‐centered nucleophile B(CN)32–. In this review the syntheses, chemical and physicochemical properties, and selected applications of cyanoborates are presented and discussed. [ABSTRACT FROM AUTHOR]

Abstract The development of stimuli-responsive difluoroboron β-diketonate materials has attracted more and more attention for their potential application in optoelectronics and functional bio-materials. In this study, we have designed and synthesized a novel photoresponsive dithienylethene-containing difluoroboron β-diketonate complex 1 by Knoevenagel condensation reaction. Its structure have been confirmed by 1H NMR, 13C NMR and HRMS (ESI). And it exhibited solvent-dependent photophysical properties in solution before visible light irradiation. Subsequently, photochromism of 1 was investigated in solution, and it was found that 1 revealed solvent-dependent and visible light-triggered NIR photochromic behaviors. Moreover, it also displayed excellent fluorescence switching behavior and photochromism in the film state upon visible light irradiation. Accordingly, the dithienylethene 1 may be acted as a novel visible light-responsive fluorescence dyes in optoelectronic materials. Graphical abstract Image 1 Highlights • Photoresponsive difluoroboron β-diketonate complex was synthesized. • It exhibited solvent-dependent and visible light-triggered NIR photochromism. • Fluorescence switching behavior and photochromism in film state were observed. [ABSTRACT FROM AUTHOR]

Abstract: 5,20‐Dibenzoyl [28]hexaphyrin(1.1.1.1.1.1) was synthesized as the first hexaphyrin bearing meso‐aroyl substituents. The meso‐dibenzoyl substituents are hydrogen‐bonded with the pyrrolic protons to stabilize an antiaromatic dumbbell conformer. Core metalation of this hexaphyrin with AuIII afforded rectangular and aromatic [26]hexaphyrin bis‐AuIII complexes, the major isomer of which was reduced with NaBH4 to give its antiaromatic 28π bis‐AuIII complex. This complex allowed facile peripheral metalation with BIII owing to the peripheral benzoyl substituents. [ABSTRACT FROM AUTHOR]

In this paper, we report the synthesis and characterization of new boron compounds derived from dithiooxamides. The compounds were characterized by NMR (1H and 13C), UV-vis, fluorescence spectroscopy, and high resolution mass spectrometry. The crystal structure of the mononuclear boron compound was determined by single-crystal X-ray diffraction analysis. The photophysical properties of the boron compounds were investigated, and we found moderate fluorescence emission (compound 2 ΦF: 4.07% and compound 4 ΦF: 2.89%). We also observed that the mononuclear complex presented greater stability. Compound 4 showed interesting luminescent properties; in solid state, it exhibited an increase in fluorescence by mechanostimuli by changing to a bright red color, and also in solution, it showed a decrease in fluorescence intensity when oxygen and air were supplied to the solution. [ABSTRACT FROM AUTHOR]

Crossed aldol reactions of the CF3-containing pseudo C2 symmetric cyclic imide 3 were carried out by way of the corresponding boron bisenolate to stereoselectively furnish the desired products 4 and this procedure allowed the preferential construction of the diastereomers of the compounds previously obtained from the acyclic counterpart 1. [ABSTRACT FROM AUTHOR]

The synthesis and properties of a variety of substituted BODIPY diesters is presented. We find that certain substitution patterns afford appreciable yields of the target compounds and that electronic effects result in predicable differential fluorescent behavior. Challenges to further water solubilize these dyes and/or provide new points of attachment for biological tagging remain, these strategies are discussed. [ABSTRACT FROM AUTHOR]

Wood is an ideal building material as it is renewable and green. However, low dimensional stability and durability might restrict its usage in structural application. Therefore, modification is needed to improve the aforementioned issues. As an environmentally friendly wood modification method, heat treatment of wood using oil as a heating medium has brought to researcher’s attention to the fact that it might serve as an excellent treatment procedure in treating wood. This paper presents a review about the effects of oil heat treatment on the properties of wood such as colour stability, dimensional stability, mechanical strength and durability against termites and fungi as well as its potential to be used as construction and building materials. The pros and cons of using oil as a heating medium in wood treatment are discussed. This review shows discrepancies between the treatment methods or procedures and its resultant findings. Moreover, the effectiveness of the treatment is governed by several factors such as the type of oils used and wood species. The objective of the present paper is to conduct a review of the published literatures regarding the properties of wood modified by oil heat treatment and the results obtained were compared systematically. [ABSTRACT FROM AUTHOR]

The density functional theory (DFT) has been used to study the surface interactions of pristine, Ni- and Pt-doped (4,4), (5,5), (7,7) and (8,8) boron nitride nanotubes (BNNTs) with ammonia (NH 3 ) molecules. To verify the impact of external electric field (EF) on the surface interactions between the nanotubes and adsorbed NH 3 molecules, in this work, the NH 3 /(4,4) BNNTs adsorbed complex system under an applied EF with strength of 3 × 10 −2  a.u. and 4 × 10 −2  a.u., along the z axis (perpendicular to the tube axis) has been investigated. It was shown that after doping of Ni and Pt atoms, the primary symmetry of BNNTs was decreased, enhancing the chemical activity of BNNTs towards NH 3 molecules and subsequent resulting in dramatic changes of their electronic properties. Our overall results indicated that, in addition to the Ni and Pt doping, the applied external EF could enhance the sensitivity of BNNTs toward NH 3 molecule, which can be considered as a new strategy of sensor fabrication. [ABSTRACT FROM AUTHOR]

A novel route to the synthesis of boron carbonitride (BC 1.61 N 0.76 ) micro-nano structures called nanosheet-decorated submicrowires is demonstrated for the first time, by annealing amorphous boron powder, natural rubber latex and ferric chloride (FeCl 3 ) at 1200 °C in flowing ammonia atmosphere. The microwires have diameters of about 200–500 nm, while the nanosheets have an average thickness of less than 20 nm. The nanosheets are mostly separated with a bending and crumpling morphology. This micro-nano structure shows good visible-light emission property at 501.2 and 592.6 nm. A combination growth mechanism of vapor-liquid-solid (VLS) and vapor-solid (VS) model is proposed to be responsible for the formation of this BC 1.61 N 0.76 micro-nano structure. [ABSTRACT FROM AUTHOR]

Abstract: In this work, CeO2−xNx materials have been prepared by the solution combustion method. All the prepared materials were characterized by powder-XRD, TEM, ICP-AES, RAMAN and XPS techniques. XRD and TEM confirmed 6-18 nm particles of CeO2−xNx materials (UC10, UC7, UC4 and UC1). Among different materials, UC10 showed the highest number of oxygen vacancies (Raman). With increase in U/C (fuel/oxidizer) ratio, the particle size decreased, whereas the specific surface area and oxygen vacancies increased. The oxygen vacancies are created because of charge imbalance and lattice distortion in ceria. The presence of N in ceria causes smaller crystallites and large specific surface area. XPS indicates N-Ce-O environment in CeO2−xNx materials. It is observed that oxygen vacancies created by nitrogen doping play an important role in cerium oxynitrides for CO oxidation reaction. The catalytic order of CeO2−xNx materials is as follows: UC10 > UC7 > UC4 > UC1. This is due to the larger number of oxygen vacancies possessed by UC10 material as compared to others. UC10 also showed an excellent 24 h time-on-stream stability for CO oxidation. The apparent activation energy of UC10 is found to be 51.1 kJ mol−1. This shows that CeO2−xNx materials are highly active and stable for CO oxidation.Graphical Abstract: [ABSTRACT FROM AUTHOR]

A facile and rapid access to a wide range of novel 1,2,3-triazoles bearing closo -decahydrodecaborate anion [B 10 H 10 ] 2− has been developed through an efficient general synthetic approach. It is based on the nucleophilic cleavage of 2-tetrahydrofuranium decaborate with sodium azide to form the known [B 10 H 9 O(CH 2 ) 4 N 3 ] 2− . This azide derivative obtained reacted with various linear alkynes (phenylacetylene, 5-chloro-1-pentyne, heptyne, octyne, N -Boc-propargylamine and diethyl acetylenedicarboxylate) by the copper(I) catalyzed [3 + 2] azide-alkyne cycloaddition reaction (CuAAC) to form click-decaborate derivatives. In absence of copper and with strained cycloalkynes, the reaction is a strain-promoted cycloalkyne-azide cycloaddition (SPAAC). All click-decaborate derivatives were obtained in pure form with high yields and characterized by 11 B, 1 H and 13 C NMR, MS-ESI, and Atomic Absorption. [ABSTRACT FROM AUTHOR]

Novel imidazole based diboron complex ( 2 ) was synthesized and characterized by multinuclear NMR and single crystal X-ray analysis. The diboron complex showed red-shifted absorption and fluorescence with significantly higher molar absorption coefficient over our recently reported imidazole based monoboron complex ( 3 ). [ABSTRACT FROM AUTHOR]

A number of heterometallic boride clusters have been synthesized and structurally characterized using various spectroscopic and crystallographic analyses. Thermolysis of [Ru3(CO)12] with [Cp*WH3(B4H8)] (1) yielded [{Cp*W(CO)2}2(μ4-B){Ru(CO)3}2(μ-H)] (2), [{Cp*W(CO)2}2(μ5-B){Ru(CO)3}2{Ru(CO)2}(μ-H)] (3), [{Cp*W(CO)2}(μ5-B){Ru(CO)3}4] (4) and a ditungstaborane cluster [(Cp*W)2B4H8Ru(CO)3] (5) (Cp*=η5-C5Me5). Compound 2 contains 62 cluster valence-electrons, in which the boron atom occupies the semi-interstitial position of a M4-butterfly core, composed of two tungsten and two ruthenium atoms. Compounds 3 and 4 can be described as hetero-metallic boride clusters that contain 74-cluster valence electrons (cve), in which the boron atom is at the basal position of the M5-square pyramidal geometry. Cluster 5 is analogous to known [(Cp*W)2B5H9] where one of the BH vertices has been replaced by isolobal {Ru(CO)3} fragment. Computational studies with density functional theory (DFT) methods at the B3LYP level have been used to analyze the bonding of the synthesized molecules. The optimized geometries and computed 11B NMR chemical shifts satisfactorily corroborate with the experimental data. All the compounds have been characterized by mass spectrometry, IR, 1H, 11B and 13C NMR spectroscopy, and the structural architectures were unequivocally established by crystallographic analyses of clusters 2-5. [ABSTRACT FROM AUTHOR]

A general and facile method to prepare unquaternized C-bound boron enolates by a ligandcontrolled O-to-C isomerization is reported. Using this protocol, C-bound pinacolboron enolates have been isolated in pure form for the first time, and have been fully characterized by NMR spectroscopy and X-ray crystallography. In contrast to the general perception, such C-boron enolates are stable without coordinative saturation at the boron. Moreover, C-boron enolates present reactivities that are distinct from the O-boron enolates, and their applications in C-O and C-C bond formations are demonstrated. [ABSTRACT FROM AUTHOR]

BODIPY (boron dipyrromethene) derivatives and iron complexes are two types of functional compounds that have found wide applications in the fields of biology and medicine. The new class of cyclometalated Fe(II) complex with NCN pincer and meso‐phenyl‐4'‐ethynyl‐2,2':6',2”‐terpyridine BODIPY ligands of formula [Fe(L)(tpy‐BODIPY)], 1, in which HL:5‐methoxy‐1,3‐bis (1‐methyl‐1H‐benzo[d]imidazol‐2‐yl)benzene, tpy‐BODIPY: 8‐(4‐phenyl‐4'‐ethynyl‐2,2':6',2”‐terpyridine) BODIPY, has been synthesized and studied as mitochondria‐targeted photodynamic therapy (PDT). Complex 1 showed photocytotoxicity in HeLa cells at 500 nm with low dark toxicity. The phototoxicity of complex 1 on the nontumorigenic MRC‐5 cell line showed the same trend observed for HeLa cells, that is moderately photocytotoxic against the nontumorigenic MRC‐5 cell line (IC50 = 36.21 μM). Moreover, complex 1 selectively localizes into mitochondria of the HeLa cells. The photophysical properties, cellular uptake, reactive oxygen species (ROS) generation, and cellular apoptosis of complex 1 have also been studied.Overall, the new Fe(II) complex with BODIPY moiety is significantly photocytotoxic in HeLa cells when irradiated with visible light of 500 nm giving as mitochondria targeting. Therefore, we present cyclometalated Fe(II) pincer complex induced mitochondria‐targeted PDT involving the BODIPY moiety that develops persuasively designed photoactivatable Fe(II) complexes. [ABSTRACT FROM AUTHOR]

A formal N-heterocyclic carbene insertion into the B–H bond of 9-BBN followed by a ring expansion reaction is reported. NHC-9-BBN adducts were reacted in one or two steps to give the corresponding di- or triazaborines. Hydride abstraction of selected species with [Ph3C]+ is facile, giving rise to 6π-aromatic cations with Lewis acidity comparable to Lewis acids commonly employed in frustrated Lewis pairs. [ABSTRACT FROM AUTHOR]

Six novel diacetoxyboron complexes of bis-β-diketones linked thienothiophene moiety were synthesized from acetoacetone by cyclization, Claisen condensation and chelation reaction. The obtained complexes were confirmed by means of 1 H NMR, FTIR, MS and elemental analysis and their electrochemical and photoluminescent properties were investigated by cyclic voltammetry, UV–vis absorption and fluorescence spectroscopy. The results showed that these diacetoxyboron complexes yielded a blue emission in DMF solution and emitted a greenish-yellow emission in powders and PMMA films. Especially, diacetoxyboron bis-β-diketonate with tert-butylphenyl thienothiophene exhibited the most intense photoluminescent intensity, highest quantum efficiency ( Φ u = 0.95) in solution and longest lifetime value ( τ = 38.42 μs) in PMMA film among these complexes. In addition, these diacetoxyboron complexes showed the low-lying LUMO energy levels (2.71–2.75 eV), which was suitable for electron transfer. [ABSTRACT FROM AUTHOR]

We reported a synthesis of quaternary B-C-N-O alloys containing boron, carbon, nitrogen, and oxygen atoms by using melamine-boric acid adduct colloidal solutions (C 3 N 6 H 6 ·2H 3 BO 3 ) as a precursor via chemical reactions. The nanocrystalline BCNO was observed by scanning electron microscope. Results from X-ray diffraction show a prominent peak at 28.13° for BCNO, indicating the interlayer distance of 0.317 nm. Elemental compositions and chemical bonds of BCNO were verified by X-ray photoemission spectroscopy. Electrical measurement of BCNO-based field effect transistors gave 0.3 cm 2 V −1 s −1 of charge mobility, 0.77 eV of band gap with 10 5 of on/off ratio. [ABSTRACT FROM AUTHOR]

Borophene, a new kind of two-dimensional materials, were successfully synthesized in experiment recently with potential applications. In this study, we have investigated the hydrogen storage performances of alkali-metal (Li, Na and K) doped three types of borophene polytypes synthesized on Ag substrate. It is found that strong binding strength exists between alkali-metal atoms and borophene, where metal atoms on borophene with separated distribution are energy more favorable than the formation of metal clusters, avoiding the aggregation problems. Polarization mechanism plays a dominant role in H 2 adsorption and the obtained storage capacities are closely related with the configurations of borophene, types of foreign atoms and the electronic interactions therein. The effects of temperature and pressure have also been taken into consideration through modified van’t Hoff equation. Our results demonstrate that Na-doped S2 and S3 and Li-doped three types of borophene could be severed as promising candidates for hydrogen storage. [ABSTRACT FROM AUTHOR]

A series of boron-nitrogen polymers (PEIPAs) were synthesized to provide a green alternative for flame retardant finishing on cotton fabrics. An organic boron compound, phenylboronic acid (PA) was successfully bonded to the branched polyethylenimine, which was confirmed by H NMR and FTIR analysis. Thermogravimetric analysis showed that the polymer with molar ratio 1:1 of ethylenimine:PA (PEIPA 1:1), presented the optimal thermal-oxidative stability. PEIPA 1:1 was easily applied on cotton fabrics through a simple dipping method with high uptake in acetone medium. The fabric with 33.8 wt% add-on got self-extinguishing ability. SEM analysis on the char morphology of the treated fabrics revealed the fire protection by the coating through intumescent flame retardant mechanism. TGIR analysis showed the coated fabric has significant reduction in the flammable volatiles production. Further improvement of the coating washing durability was achieved by a novel formaldehyde-free cross-linking treatment. The new washing stable coating achieved LOI values 29.6 and 23.2% before and after repeated launderings respectively with 30 wt% add-on. Cone calorimetry analysis showed that the total heat releases of PEIPA 1:1 treated sample and cross-linked sample (PEIPA 3:1/NeoFR treated) were decreased by 30.3 and 45.5% respectively. Smoke analysis revealed that the treated fabrics have significant decrease in CO/CO ratio, indicating an effective flame inhibition in gas phase. The novel coatings, simple to synthesize and easy to apply with low waste, are suitable alternative to toxic halogenated flame retardants for cellulosic products. [ABSTRACT FROM AUTHOR]

In this report, the enantioselective, copper-catalyzed borylation of ß-amidoacrylates is disclosed. A broad variety of biologically important a-aminoboronates has been prepared with consistently high levels of enantiocontrol using an inexpensive copper catalyst and a commercially available chiral ligand. The method can be applied to the synthesis of novel boron-containing dipeptides and hemiboronates. [ABSTRACT FROM AUTHOR]

Heteroatom-rich organoboron compounds have attracted attention as modulators of enzyme function. Driven by the unmet need to develop chemoselective access to boron chemotypes, we report herein the synthesis of α- and β-aminocyano(MIDA)boronates from borylated carbonyl compounds. Activity-based protein profiling of the resulting β-aminoboronic acids furnishes selective and cell-active inhibitors of the (ox)lipid-metabolizing enzyme α/β- hydrolase domain 3 (ABHD3). The most potent compound displays nanomolar in vitro and in situ IC50 values and fully inhibits ABHD3 activity in human cells with no detectable crossreactivity against other serine hydrolases. These findings demonstrate that synthetic methods that enhance the heteroatom diversity of boron-containing molecules within a limited set of scaffolds accelerate the discovery of chemical probes of human enzymes. [ABSTRACT FROM AUTHOR]

Novel boron-containing drugs have recently been suggested as a new class of pharmaceuticals. However, the majority of current boron-detection techniques require expensive facilities and/or tedious pretreatment methods. Thus, to develop a novel and convenient detection method for boron-based pharmaceuticals, imine-type boron-chelating-ligands were previously synthesized for use in a fluorescent sensor for boronic acid containing compounds. However, the fluorescence quantum yield of the imine-type sensor was particularly low, and the sensor was easily decomposed in aqueous media. Thus, in this paper, we report the development of a novel, convenient, and stable fluorescent boron-sensor based on O- and N-chelation (i.e., 2-(pyridine-2yl)phenol), and a corresponding method for the quantitative and qualitative detection of boronic acid-containing compounds using this commercially available sensor is presented. [ABSTRACT FROM AUTHOR]

Inspired by the fascinating finding of all-boron fullerene B 40 ( Nat Chem , 2014, 6, 727), we propose a new and effective strategy to construct a series of typical Donor-Acceptor (D-A) frameworks via linking the superalkali M 3 O (M = Li and K) unit with the low ionization potential to the B 40 nanocage with large electron affinity. By means of the density functional theory computations, we have systematically investigated the structures, electronic properties, the first and second hyperpolarizabilities of these modified B 40 nanocage systems. Owing to the formation of a B–O chemical bond, these composite systems (M 3 O) n -B 40 (M = Li and K, n = 1 and 2) can possess the considerably large binding energy ranging from 57.0 to 99.8 kcal/mol, indicating their high structure stabilities. Compared with the pristine B 40 nanocage, linking the superalkali M 3 O can effectively narrow the wide energy gap from the original 2.86 eV to 0.61–1.11 eV, and significantly increase the first and second hyperpolarizabilities to as large as 5.00 × 10 4 –2.46 × 10 5 au and 1.48 × 10 7 –4.85 × 10 8 au, respectively, owing to the occurrence of evident electron transfer process in this kind of typical D-A framework. These fascinating findings will be advantageous for promoting the potential applications of the inorganic boron-based nanosystems in the new type of electronic nanodevices and high-performance nonlinear optical materials. [ABSTRACT FROM AUTHOR]

Conspectus: Due to the complexity of biological systems and samples, specific capture and targeting of certain biomolecules is critical in much biological research and many applications. cis-Diol-containing biomolecules, a large family of important compounds including glycoproteins, saccharides, nucleosides, nucleotides, and so on, play essential roles in biological systems. As boronic acids can reversibly bind with cis-diols, boronate affinity materials (BAMs) have gained increasing attention in recent years. However, real-world applications of BAMs are often severely hampered by three bottleneck issues, including nonbiocompatible binding pH, weak affinity, and difficulty in selectivity manipulation. Therefore, solutions to these issues and knowledge about the factors that influence the binding properties are of significant importance. These issues have been well solved by our group in past years. Our solutions started from the synthesis and screening of boronic acid ligands with chemical moieties favorable for binding at neutral and acidic pH. To avoid tedious synthesis routes, we proposed a straightforward strategy called teamed boronate affinity, which permitted facile preparation of BAMs with strong binding at neutral pH. To enhance the affinity, we confirmed that multivalent binding could significantly enhance the affinity toward glycoproteins. More interestingly, we observed that molecular interactions could be significantly enhanced by confinement within nanoscale spaces. To improve the selectivity, we investigated interactions that govern the selectivity and their interplays. We then proposed a set of strategies for selectivity manipulation, which proved to be useful guidelines for not only the design of new BAMs but also the selection of binding conditions. Applications in metabolomic analysis, glycoproteomic analysis, and aptamer selection well demonstrated the great potential of the prepared BAMs. Molecular imprinting is an important methodology for creating affinity materials with antibody-like binding properties. Boronate affinity-based covalent imprinting is a pioneering approach in molecular imprinting, but only a few cases of successful imprinting of glycoproteins by this method were reported. With sound understanding of boronate affinity, we developed two facile and generally applicable boronate affinity-based molecular imprinting approaches. The resulting boronate affinity molecularly imprinted polymers (MIPs) exhibited dramatically improved binding properties, including biocompatible binding pH range, enhanced affinity, improved specificity, and superb tolerance to interference. In terms of nanoconfinement effect, we explained why the binding pH range was widened and why the affinity was enhanced. The excellent binding properties made boronate affinity MIPs appealing alternatives to antibodies in promising applications such as disease diagnosis, cancer-cell targeting, and single-cell analysis. In this Account, we survey the key aspects of BAMs, the efforts we made to solve these issues, and the connections between imprinted and nonimprinted BAMs. Through this survey, we wish to pave a sound fundamental basis of the dependence of binding properties of BAMs on the nature and structure of the ligands and the supporting materials, which can facilitate the development and applications of BAMs. We also briefly sketch remaining challenges and directions for future development. [ABSTRACT FROM AUTHOR]

Borate was regarded as an interesting material for a broad range of applications. Here, we had prepared a novel borate-based controlled-release inhibitor to improve the anticorrosion performance of Q235-b in 1 M HCl. The effective components released by the inhibitor were boron and sodium, and its anticorrosion performance was investigated by various electrochemical methods The potentiodynamic polarization curve results indicated that the borate-based inhibitor showed a clear anodic-type inhibitor characteristic, and a great improvement of the resistance was obtained from the electrochemical impedance spectroscopy, resulting from the formation of a passive film with Fe O B structure on the Q235-b surface. The formation process followed the Langmuir isotherm well, and the passive film showed a self-healing capability, which confirmed by the electrochemical noise. Further, the anticorrosion capability of the inhibitor gradually increased with the increasing release time. After 21 days of release, the boron concentration reached 125 mg L −1 , the anticorrosion efficiency was over 97%, and a smooth surface was observed on the Q235-b surface from electron microscopy. According to these results, we believed that the borate-based controlled-release inhibitor displayed a satisfactory capability to suppress corrosion on the Q235-b surface in 1 M HCl. The present work provided a novel concept for the development of corrosion inhibitor. [ABSTRACT FROM AUTHOR]

We describe an unusual net [2+2] cycloaddition reaction between boron alkylidenes and unactivated alkenes. This reaction provides a new method for the construction of carbocyclic ring systems bearing versatile organoboronic esters. Aside from surveying the scope of this reaction, we provide details about the mechanistic underpinnings of this process, and examine its application to the synthesis of the natural product aphanamal. [ABSTRACT FROM AUTHOR]

Very recently, borophene (atomic-thin two-dimensional boron sheet) has been successfully synthesized on the Ag(111) surface by deposition. Two kinds of structures were found. However, the identification of the monolayer boron sheets grown on the metal substrate, as well as the stability of different 2D boron sheets, is controversial. By performing the first-principles calculations, present study investigates the atomic structure, stability, and electronic properties of the most possible boron sheets grown on metal surface, namely, buckled triangular, β, and χ types of crystal lattice. Our result shows that all the three freestanding sheets are thermodynamically unstable and all are metallic. On the other hand, our result indicates the Ag(111) substrate stabilize these sheets. Additionally, our simulated STM images of these monoatomic-thin boron sheets on Ag(111) surface reproduce the experiment observations well and clearly identify the as-grown boron sheets. [ABSTRACT FROM AUTHOR]

Two unusual organic templated borates, [Al(C 3 H 12 N 2 )(C 2 H 7 N)]·[B 5 O 10 ] ( 1 ) and [Zn(HCOO)(1,2-dap) 2 ]·[B 5 O 7 (OH) 4 ] ( 2 ) were synthesized under solvothermal conditions ([HCOO] − = formic ion; 1,2-dap = 1,2-diaminopropane). The obtained 1 and 2 borates were characterized by using elemental analysis, FTIR, PXRD, TG, and single-crystal X-ray diffraction. 1 crystallizes in the Pbca space group and shows a 3D anionic framework based on AlO 4 and B 5 O 10 clusters. Interestingly, there are two kinds of organic amines in the structure: one was 1, 2-dap, while the other was ethylamine from the in situ reaction of 1,2-dap. 2 crystallizes in the P -1 space group, and consists of a [Zn(HCOO)(1,2-dap) 2 ] + cation and [B 5 O 6 (OH) 4 ] − polyanion, the presence of [HCOO] − suggests the in situ decomposition of DMF (DMF = N, N-Dimethylformamide). [ABSTRACT FROM AUTHOR]

In this study, diamond crystals co-doped with boron and nitrogen were synthesized via a temperature gradient method at 5.3–5.8 GPa and 1300–1550 °C by adding B and N dopants to a system of carbon and an Fe-based solvent catalyst. The obtained co-doped diamond crystals were characterized via optical microscopy (OM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. Our results indicated that the obtained B/N-co-doped diamond crystals were green in color and nearly transparent. The surface characteristics were different for the (100) and (111) crystal faces. In the B/N-co-doped diamonds, B, C, and N combined with each other and formed stable chemical bonds. The nitrogen concentration of the co-doped diamond crystals was much higher than that of the single doped crystals, and the form of nitrogen atoms was also different. The Raman characteristic peak of the co-doped diamond crystals almost did not shift as compared to that of the undoped or single doped crystals. [ABSTRACT FROM AUTHOR]

We report the synthesis and characterization of a novel series of main-chain boron-containing conjugated polymers (CPs), boron "doped" polyacetylenes (BPAs), which represent the first examples of main-chain boron-containing CPs without aromatic moieties within the polymer backbone, potentially enhancing electronic delocalization along the main-chain. These polymers are characterized by NMR, absorption and emission spectroscopy, cyclic voltammetry, theoretical calculation, and fluoride titration experiments, providing detailed understanding of the effects from different cross-conjugated side-chains on the physical and electronic properties of this new class of boron-containing polymers. [ABSTRACT FROM AUTHOR]

Boron suboxide (B6O)−based materials have shown good properties which make them good candidates for cutting tool and other applications where abrasive wear resistance is important. The objective of this study was to optimize the production of B6O at ambient pressure by varying reaction temperature and time. B6O powders were produced from the reaction between boric acid and amorphous boron powders at the reaction temperatures between 300°C and 1400°C for 6 h. The powders produced were characterized in terms of particle size, phase analysis and composition, product yield, as well as morphology. Increase in temperature increased both the yield as well as the particle size of the produced powders. X-ray diffraction (XRD) pattern obtained also showed improved crystallinity of the produced powder as the temperature increases. Scanning electron microscopy (SEM) images of the synthesized powder at higher temperature clearly showed improved crystallinity (star-like crystals) as the reaction temperature was increased. The B6O powders synthesized at 1300°C for 6 h had the optimum yield of over 95%. [ABSTRACT FROM PUBLISHER]

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The dissociation of O2and HO2are important reactions that occur at the cathode of fuel cells and require catalysts to proceed. There is a need to replace the presently used platinum catalyst with less expensive materials. Modelling has been used to identify potential two-dimensional catalysts such as boron- and nitrogen-doped graphene. Here, the possibility of boron nitride nano-ribbons and nano-tubes which do not require doping are considered. Density functional calculations are used to show that O2and HO2can bond to zig–zag and armchair boron nitride nano-ribbons and nano-tubes. The bond dissociation energies (BDEs) to remove an O and an OH from O2and HO2bonded to the boron nitride ribbons and tubes are calculated and are a measure of the catalytic effectiveness of the boron nitride structures. The results show that both the zig–zag and armchair boron nitride ribbons could be a catalyst for HO2dissociation but not O2dissociation. However, zig–zag boron nitride nano-tubes are shown not to be effective catalysts for the dissociation of O2or HO2.An armchair boron nitride nano-tube is shown to have a very low BDEs to remove OH from HO2bonded to it and could be an affective catalyst. [ABSTRACT FROM PUBLISHER]

Two BINOL based boronate esters, namely (S)-2 and (S)-3, were designed and synthesized. Fluorescent recognition studies of (S)-2 towards enantiomers of mandelic acid revealed that sensor (S)-2 exhibited high fluorescent enantioselective response towards mandelic acid. The other boronate ester (S)-3 which did not have hydroxyl group in the minor groove of BINOL did not show any fluorescent chiral discrimination. Their enantioselective recognition was also studied by means of 1 H NMR spectroscopy. The results indicated that the sensor (S)-2 was very promising as a chiral fluorescent sensor for the recognition of chiral carboxylic acid in THF solvent. Theoretically predicted hydrogen bonding interactions revealed a favorable chiral recognition between the receptor and l -mandelic acid, which is well correlated with experimentally observed enantioselective recognition phenomenon. [ABSTRACT FROM AUTHOR]

Until recently, the chemistry of boronyl (BO), a diatomic radical isolectronic with the cyano (CN) species, has remained unknown. The boronyl group is characterized by a boron-oxygen multiple bond, and because of the inherent electron deficiency of the boron atom, boronyls (RBO) are highly reactive and typically only exist in their cyclotrimeric form (RBO)3. Due to their invaluable role as reactants, the isolation of the monomers in gas phase experiments has been extensively sought after by the organic synthesis and physical organic chemistry communities but never achieved. Besides the interests from a physical organic and synthetic point of view, boronyls also play a role as reaction intermediates in boron-assisted rocket propulsion systems.In this Account, we review recent experimental work in which gas phase organo boronyl monomers (RBO) are formed via bimolecular reactions of the boronyl radical (BO) with C2-C6 unsaturated hydrocarbons. The investigated hydrocarbons are widely exploited as fuels, and their reactions with boronyl radicals under single collision conditions lead to the formation of organo boronyls. Our studies also elucidate the mechanisms of their formation reactions thus furnishing a comprehension at the molecular level of this reaction class. The variety of the employed hydrocarbon substrates has allowed us to systematically classify the chemical behavior of the boronyl radicals. With the exception of the case of the dimethylacetylene reaction, the boron monoxide radical versus atomic hydrogen exchange mechanisms were always open leading to the formation of highly unsaturated organo boronyl monomers (RBO), which could be easily identified because they cannot trimerize under single collision conditions.Besides the hydrogen displacement pathway, methylacetylene, dimethylacetylene, and propylene, carrying one or two methyl groups, were also found to eliminate a methyl group. In all systems, the reactions were barrierless, indirect, and initiated by addition of the boron monoxide radical to the π electron density of the hydrocarbon molecule, with the radical center located at the boron atom of the BO radical, thus leading to doublet radical intermediates. These intermediates either decompose via hydrogen or methyl loss or isomerize prior to their decomposition via atomic hydrogen or migration of the BO moiety. A consistent trend suggests that all exit transition states are rather tight with those involved in the hydrogen atom loss depicting exit barriers of typically 25 to 35 kJ mol-1, whereas the methyl loss pathways are associated with tighter exit transition states located about 30-50 kJ mol-1 above the separated products. Further, the overall energetics suggest that those bimolecular reactions are exoergic by 40-90 kJ mol-1. These findings confirm that this reaction class leads to the formation of highly unsaturated organo boronyl molecules. [ABSTRACT FROM AUTHOR]

A homogeneous series of well-defined butadiynylene-BODIPY oligomers containing up to four BODIPY moieties have been synthesized from a “one-pot” oxidative homocoupling reaction of 2,6-di((trimethylsilyl)ethynyl)BODIPY. Further derivation of the resultant BODIPY dimer generates a water-soluble, red-emitting butadiyne-linked BODIPY dimer with pyridinium ions, which can ratiometrically detect viscosity, based on the two fluorescent conformers with the two BODIPY cores twisted and planar to each other depending on the viscosity of the environment. [ABSTRACT FROM AUTHOR]

The thickness and interfacial geometry of hexagonal boron nitride (hBN) films grown by chemical vapor deposition on polycrystalline nickel foils is studied using low-energy electron microscopy (LEEM). The reflectivity of the electrons, measured over an energy range of 0–20 eV, reveals distinct minima and maxima. The measured data is compared with simulations based on a first-principles description of the electronic structure of the material. From this comparison, the number of hBN layers and the separation between the lowest hBN layer and the nickel surface is deduced. The coupling of interlayer states of the hBN to both image-potential and Shockley-type surface states of the nickel is discussed, and the dependence of the reflectivity spectra on the surface orientation of nickel grains is examined. [ABSTRACT FROM AUTHOR]

Tin(IV) catalysis allows isolation of a boron dipyrromethene derivative bearing a solitary strap around the boron center. The conditions favor internal cyclization without contamination by side products and provide high yields of product in good purity. A phenolate-based strap imposes chirality and causes geometrical distortion of the dipyrrin. Relatively strong fluorescence is observed for single crystals, evaporated films, and adsorbed layers. Single-crystal absorption and emission spectra resemble those observed from solution with contributions from a dimer. [ABSTRACT FROM AUTHOR]

Catalytic amounts of B(C6F5)3 promote the ring opening and subsequent isomerization of a series of unactivated cyclopropanes to afford terminal olefins in good yields when a hydrosilane and 2,6-dibromopyridine are employed as additives. [ABSTRACT FROM AUTHOR]

We present the selective atom economical synthesis of borasiloxanes using a multi-component approach directly by the one-pot ruthenium catalysed reaction of boranes, silanes and water. [ABSTRACT FROM AUTHOR]

A pyrrole-cleaving modification to transform boron(III) meso-triphenylsubporphyrin into boron(III) meso-triphenylsubchlorophin has been developed. Boron(III) subchlorophins thus synthesized show absorption and fluorescence spectra that are roughly similar to those of boron(III) subchlorins, but B-methoxy boron(III) subchlorophin showed considerably intensified fluorescence and a small Stokes shift. Peripheral modification reactions of B-phenyl boron(III) subchlorophin such as regioselective nitration with Cu(NO3)2⋅3 H2O, ipso-substitution reactions of boron(III) α-nitrosubchlorophin with CsF and CsCl, and Pd-catalyzed cross-coupling reactions of boron(III) α-chlorosubchlorophin with arylacetylenes, have been also explored to tune the optical properties of subchlorophins. [ABSTRACT FROM AUTHOR]

A new multifunctional probe made up of boron dipyrromethene (BODIPY) and benzimidazole neighboring phenol was designed and synthesized. This probe displays a colorimetric recognition of Hg 2+ and a ‘turn off’ fluorescent response to Cr 3+ at physiological condition. The ‘in situ’ ensemble of host and Hg 2+ shows a selective and ratiometric detection of I − via the formation of three-component ensemble. These systems were further used to detect their corresponding targets in real water sample with acceptable recovery. Compared to the comprehensive report of the single-target responsive chemosensor, these results provided an approach to design the challenging multifunctional probe. [ABSTRACT FROM AUTHOR]

Both hypervalent organoiodine(III) compounds and boronic acids/esters are non-toxic and considered as environment-friendly compounds and have had a remarkable impact on the field of synthetic organic chemistry. Numerous transformations have been carried out using hypervalent organoiodine(III) or boronic acids/esters - taken separately - with other reactants, but transformations with these two reagents taken together are comparatively less well reported. In this mini-review, diverse reactions carried out with these two substrates in the presence of each other, have been discussed. Various functionalizations of boronic compounds, promoted by hypervalent organoiodine(III) reagents, both in the presence and absence of transition metals, have been reviewed. Different metal-free iodine(III)-boron exchange reactions providing iodonium salts, various ipso transformations of boronic acids/esters and metal-catalyzed cross-coupling reactions of boronic compounds with hypervalent organoiodine(III) reagents are the prime focal areas of this article. Mechanistic aspects for certain reactions have also been delineated. [ABSTRACT FROM AUTHOR]

We have synthesized a series of salicylaldimine difluoroboron complexes that contain carbazole moieties. Substituents on the carbazole and on the benzene rings of the salicylaldimine moiety influenced the intramolecular charge transfer (ICT) emissions of these complexes. Interestingly, the synthesized difluoroboron complexes emitted strong light in the solid state under UV irradiation and exhibited reversible mechanofluorochromism behavior. The emission of a pristine sample of 3-[4-(3,6-di- tert-butyl-9 H-carbazol-9-yl)phenyl]-2,2-difluoro-2 H-2λ4,3λ4-benzo[ e][1,3,2]oxazaborinine ( TCH) at 488 nm redshifted to 571 nm upon grinding, and the ground powder exhibited an orange emission. Fuming with dichloromethane (DCM) or heating at 200 °C for 2 min led to the recovery of the original solid state that emitted a bluish-green light. XRD patterns illustrate that the mechanofluorochromism features are reasonable for the transformation between the crystalline and amorphous states. [ABSTRACT FROM AUTHOR]

π-Conjugated boron complexes have been considered as excellent fluorescent dye system and utilized in various fields, such as organic electronics, photonics, nanoemitters and dyestuff industry. In this paper, we developed a fluoroboron coordination by employing in situ generated BF 3 ·H 2 O as fluoroboron souce and afforded a series of novel species of N,O π-conjugated boron complexes. Moreover, we achieved the Suzuki cross-coupling reaction of iodo-substituted complex with different boronic acids to further expand the structural diversity of N,O π-conjugated fluoroboron complexes. [ABSTRACT FROM AUTHOR]