3,218 results
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2. Ultrasensitive Detection of Tetracycline Using Boron and Nitrogen Co-Doped Graphene Quantum Dots from Natural Carbon Source as the Paper-Based Nanosensing Probe in Difference Matrices
- Author
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Hai Linh Tran, Win Darmanto, and Ruey-An Doong
- Subjects
boron ,nitrogen co-doped graphene quantum dots (B,N-GQDs) ,passion fruit juice ,microwave-assisted ,paper strip sensor ,tetracycline ,Chemistry ,QD1-999 - Abstract
Herein, the boron and nitrogen co-doped 0-dimensional graphene quantum dots (B,N-GQDs) with high quantum yield (QY) were synthesized via microwave-assisted hydrothermal method at 170 °C for 20 min using fresh passion fruit juice and boric acid as the starting materials. The 3–6 layers of B,N-GQDs with mean particle size of 9 ± 1 nm were then used for ultra-sensitive and selective detection of tetracycline in aqueous and biological media. The hybridization of boron and nitrogen atoms into the GQD structures increases the intensity of electronegative, resulting in the enhancement of QY to 50 ± 1%. The B,N-GQDs show their excellent analytical performance on tetracycline determination after 2 min of reaction under an optimal condition at pH 5. The linear range of 0.04–70 µM and with limits of detection (LOD) of 1 nM in phosphate buffer saline (PBS), 1.9 nM in urine and 2.2 nM in human serum are obtained. Moreover, the high selectivity of tetracycline by B,N-GQDs over the other 23 interferences is observed. The π-π interaction and electron donor-acceptor principle play pivotal roles in enhancing the ultra-sensitivity and selectivity of B,N-GQDs toward TC detection. Moreover, the B, N-GQD based paper nanosensor exhibits an excellent analytical performance on visual detection of 0.1–30 µM TC in human serum. Results of this study clearly indicate the feasibility of synthesis of B,N-GQDs derived from passion fruit juice for ultrasensitive tetracycline detection, which can open an avenue to use natural products for the preparation of environmentally benign and biocompatible carbon nanomaterials for highly sensitive detection of drugs, antibiotics, organic compounds and biomarkers.
- Published
- 2020
- Full Text
- View/download PDF
3. Catalytic graphitization of boron on the fabrication of high-performance carbon papers for gas diffusion layers in PEMFCs
- Author
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Chenying Song, Hailong Li, Li Chen, Tao Fang, and Jian Hu
- Subjects
inorganic chemicals ,Fabrication ,Materials science ,chemistry.chemical_element ,complex mixtures ,Catalysis ,stomatognathic system ,Gaseous diffusion ,Boron ,Dissolution ,QD1-999 ,Carbon paper ,Catalytic graphitization ,Precipitation (chemistry) ,Process Chemistry and Technology ,General Chemistry ,Resin-derived carbon ,carbohydrates (lipids) ,stomatognathic diseases ,Chemistry ,chemistry ,Chemical engineering ,Carbon ,Solid solution - Abstract
Boron was introduced into carbon papers (CPs) to catalyze their graphitization in this paper. The results showed the graphitization of CPs was moved from 2400 °C to 2100 °C. At 2100 °C, boron substituted carbon atoms in the hexagonal carbon lattices to form a solid solution, and the catalytic mechanism was dissolution and precipitation. CPs with excellent electrical conductivity and good permeability were prepared at lower temperature. Thus, the boron-doping method provides a new way to prepare high performance CPs at lower costs.
- Published
- 2021
4. Facile synthesis of amorphous nickel iron borate grown on carbon paper as stable electrode materials for promoted electrocatalytic urea oxidation
- Author
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Abdulaziz M. Alsalman, Abdullah M. Al-Mayouf, Mahmoud Hezam, Saba A. Aladeemy, Zeyad Almutairi, Prabhakarn Arunachalam, and Mabrook S. Amer
- Subjects
Tafel equation ,Materials science ,chemistry.chemical_element ,General Chemistry ,Catalysis ,Amorphous solid ,Nickel ,chemistry.chemical_compound ,chemistry ,X-ray photoelectron spectroscopy ,Transmission electron microscopy ,Urea ,Boron ,Nuclear chemistry - Abstract
The development of greatly stable and cost-effective electrocatalysts for urea electro-oxidation reactions (UERs) is urgent and challenging for promoting urea removal in the wastewater and advanced energy conversion devices. We demonstrated that nickel-iron borate (NiFe-B) electrocatalysts supported on carbon paper (CP) for UERs through a one-pot solvothermal method. NiFe-B electrocatalysts were obtained with numerous Ni/Fe molar ratios in the precursors, and the physicochemical features of the NiFe-B were examined by X-ray diffraction, scanning and transmission electron microscope, and X-ray photoelectron spectroscopy. The optimized NiFe-B/CP exhibited a low onset potential (Eonset = 0.287 V vs. SCE) with a Tafel slope of 27.9 mV/dec on CP, demonstrating much greater performance UERs. Furthermore, the NiFe-B/CP catalysts have shown a superior activity for the UERs in alkaline solution and exhibit more than two-fold enhancement in activity than Ni-B. Facile, cost-effective fabrication and highly efficient urea oxidation create the NiFe-B electrodes as attractive materials for UERs.
- Published
- 2022
5. Borate-Modified, Flame-Retardant Paper Packaging Materials for Archive Conservation
- Author
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Yuhu Li, Jing Cao, Kaiyuan Li, Bingjie Mai, Xiaolian Chao, Ming Cao, Juanli Wang, and Jiaxin Li
- Subjects
Materials science ,Chemical engineering ,chemistry ,Materials Science (miscellaneous) ,chemistry.chemical_element ,Environmental Science (miscellaneous) ,Boron ,Fire retardant - Published
- 2022
6. Catalytic graphitization of boron on the fabrication of high-performance carbon papers for gas diffusion layers in PEMFCs.
- Author
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Chen, Li, Fang, Tao, Song, Chenying, Li, Hailong, and Hu, Jian
- Subjects
- *
CARBON paper , *GRAPHITIZATION , *DIFFUSION , *BORON , *ELECTRIC conductivity , *SOLID solutions , *LOW temperatures - Abstract
Boron was introduced into carbon papers (CPs) to catalyze their graphitization in this paper. The results showed the graphitization of CPs was moved from 2400 °C to 2100 °C. At 2100 °C, boron substituted carbon atoms in the hexagonal carbon lattices to form a solid solution, and the catalytic mechanism was dissolution and precipitation. CPs with excellent electrical conductivity and good permeability were prepared at lower temperature. Thus, the boron-doping method provides a new way to prepare high performance CPs at lower costs. [Display omitted] • The graphitization degree of 88.1% for CPs is reached at 2100 °C by boron-doping, whereas the value for the undoped CPs 2100 °C is only 34.3%; • The highly conductive CPs are achieved at lower graphitization temperatures without scarifying their gas permeability. • The graphitization temperature of CPs can be lowered as much as 300 °C. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
7. Preparation and flame-retardant mechanism of flame-retardant air filter paper
- Author
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Cheng Huang, Huifang Zhao, Yan Li, and Lizheng Sha
- Subjects
Thermogravimetric analysis ,Spectrum analyzer ,Environmental Engineering ,Materials science ,Scanning electron microscope ,chemistry.chemical_element ,Bioengineering ,humanities ,Limiting oxygen index ,fluids and secretions ,chemistry ,Fourier transform infrared spectroscopy ,Composite material ,Boron ,Waste Management and Disposal ,reproductive and urinary physiology ,Fire retardant ,Air filter - Abstract
Four flame retardants and styrene-acrylic latex were used to make flame-retardant air filter paper via emulsion impregnation. The compositions and flame retardant mechanism of the flame retardants were investigated by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The flame retardance of air filter paper was evaluated using TGA and limiting oxygen index (LOI) meter, and the physical properties and pore structure of the flame-retardant air filter paper were measured using stiffness tester, burst tester, and aperture analyzer. The results showed that the optimal ratio of flame retardant to styrene-acrylic latex was 1:1.4. The synergistic effect of boron, phosphorus and nitrogen made FR3 have good flame-retardant effect on air filter paper. Air filter paper with FR3 also had good physical strength and suitable pore size distribution.
- Published
- 2019
8. Screening for boron tolerance in wheat (T. aestivum) by solution culture in filter paper
- Author
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Chantachume, Y., Smith, D., Hollamby, G.J., Paull, J.G., and Rathjen, A.J.
- Published
- 1995
9. Efficient and reversible removal of boric acid by chitosan/tannic acid functional paper
- Author
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Shoujuan Wang, Cheng Wu, Nannan Xia, Fangong Kong, Qin Wu, Keyin Liu, and Sun Haodong
- Subjects
Environmental Engineering ,Langmuir adsorption model ,chemistry.chemical_element ,Bioengineering ,macromolecular substances ,Dissociation (chemistry) ,Boric acid ,symbols.namesake ,chemistry.chemical_compound ,Adsorption ,chemistry ,Desorption ,Tannic acid ,symbols ,Cellulose ,Boron ,Waste Management and Disposal ,Nuclear chemistry - Abstract
It is important to remove excessive concentrations of boric acid from water because it can lead to environmental problems. However, current adsorbents are limited in separating boric acid from water due to their low desorption capability and poor selectivity for boric acid. In this study, the authors developed a functional cellulosic paper via crosslinking cellulose and tannic acid with chitosan to efficiently and reversibly remove boric acid from water. The adsorption capacity reached 769 mg/m2 according to the Langmuir model. The corresponding desorption rate of the chitosan/tannic acid-modified paper exceeded 80% in the whole flow rate region ranging from 15 to 250 mL/h. The reversible adsorption and desorption of boric acid were attributed to the formation and dissociation of the borate bond between the tannic acid and boric acid, respectively, at different pH values. This study improved the selectivity, batch adsorption, expensive carriers, and desorption difficulties of existing boric acid adsorption materials. This approach offers a new way to design highly efficient adsorption/desorption materials by constructing reversible chemical bonds for removal of other pollutants.
- Published
- 2019
10. Abstracts of Papers Presented to the 2nd Annual Research Group Meeting of the Irish Tillage and Land Use Society (ITLUS) 24 March, 1994
- Published
- 1994
11. Examination of the Alkali Impregnated Filter Paper for the Measurement of Gas Phase Boron Compounds used in the Inside Stack Sampler
- Author
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Akie Matsui, Takahisa Yamazaki, Mizuka Kido, Seiichi Toriyama, Tokuhiro Nakamura, Toshiaki Mizoguchi, Makoto Shimabayashi, Masataka Nishikawa, Kyohei Yoneda, Noriyuki Nakatani, and Atsushi Tanaka
- Subjects
Restricted range ,Filter paper ,Stack (abstract data type) ,Chemistry ,Filter (video) ,Analytical chemistry ,chemistry.chemical_element ,Gas concentration ,Alkali metal ,Boron ,Gas phase - Abstract
For the emission gas concentration measurement of sublimable gas phase boron compounds, the optimal collector material applied to the inside stack sampler (the type-I stack sampler developed in our previous article) was examined. The collection efficiency of alkali impregnated filter paper of K2CO3, Na2CO3, LiOH and Ba(OH)2 was investigated by using artificial stack.It was revealed that K2CO3 and Na2CO3 filter papers have a high collection efficiency and fully applicable to the type-I stack sampler. However, LiOH and Ba(OH)2 filter papers have a restricted range of applicable condition.
- Published
- 2007
12. Enhancing Mechanical Properties of Ceramic Papers Loaded with Zeolites using Borate Compounds as Binders
- Author
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Miguel Angel Mario Zanuttini, Ramiro Marcelo Serra, Maria Alicia del H. Ulla, Viviana Guadalupe Milt, and Juan Pablo Cecchini
- Subjects
Environmental Engineering ,Materials science ,lcsh:Biotechnology ,chemistry.chemical_element ,Bioengineering ,engineering.material ,Colemanite ,law.invention ,Zeolitic fibrous catalysts ,law ,lcsh:TP248.13-248.65 ,Flexible structured catalysts ,Calcination ,Ceramic ,Composite material ,Boron ,Zeolite ,Waste Management and Disposal ,Faujasite ,Polyelectrolyte ,Ulexite ,Borate binders ,chemistry ,Chemical engineering ,Ceramic papers ,visual_art ,engineering ,visual_art.visual_art_medium - Abstract
NaY zeolite-containing ceramic papers were prepared by a papermaking technique with a dual polyelectrolyte retention system that implied the use of cationic and anionic polymers. To improve their mechanical properties, we found that some borate compounds could be successfully used as ceramic binders. Three types of sodium and/or calcium borates were tested as binders: colemanite, nobleite, and anhydrous ulexite. The improvement in the mechanical properties depends both on the borate used and on the calcination temperature. By XRD it was determined that the faujasite structure collapsed after calcination at 700°C, which limited the final calcination temperature of zeolitic ceramic papers. Different amounts of NaY zeolite were added to ceramic papers and, as observed by SEM, faujasite particles were well distributed throughout the ceramic paper structure. Ceramic papers containing 1.2 wt.% zeolite after calcination at 650°C resulted in structured catalysts that were easy-to-handle, and which can be adapted to different conformations.
- Published
- 2012
13. Screening for boron tolerance in wheat (T. aestivum) by solution culture in filter paper
- Author
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A. J. Rathjen, G. J. Hollamby, David J. Smith, Y. Chantachume, and Jeffrey G. Paull
- Subjects
inorganic chemicals ,Filter paper ,Chemistry ,Soil Science ,chemistry.chemical_element ,Plant physiology ,Plant Science ,Horticulture ,Dry weight ,Botany ,Shoot ,Poaceae ,Phytotoxicity ,Genetic variability ,Boron - Abstract
A new screening technique for tolerance to high concentrations of boron, namely a filter paper technique, and a soil experiment were compared to investigate the response of wheat genotypes known to differ in tolerance to high concentrations of boron. Under high boron concentrations in filter papers, the more tolerant genotypes had significantly longer roots than those of the more sensitive genotypes. There was no significant correlation between the root lengths at the control treatment and the other three boron treatments (50, 100, 150 mg B L-1). Thus, the differences in root lengths at the high boron treatments could not be attributed to inherent differences in root growth but to the genetic variation in response to high boron concentrations among varieties. Root lengths at the three boron treatments in filter papers were highly significantly correlated with the three characters determined for plants grown in soil containing high levels of boron, namely the concentrations of boron in the shoots, plant dry weight and plant symptoms, indicating that root length could be used as a selection criterion in a genetic study or breeding program for boron tolerance.
- Published
- 1995
14. Boron accumulation and tolerance of hybrid poplars grown on a B-laden mixed paper mill waste landfill
- Author
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Rainer Schulin, Christopher J. Rog, Rainer Rees, Brett Robinson, and Andreas Papritz
- Subjects
Limiting factor ,Environmental Engineering ,engineering.material ,Plant Roots ,Nutrient imbalance ,Wisconsin ,Environmental Chemistry ,Soil Pollutants ,Revegetation ,Waste Management and Disposal ,Phytomanagement ,Boron ,Hemiboreal ,Hybrid poplars ,Trace element contamination ,Root traits ,business.industry ,Chimera ,Pulp (paper) ,Soil classification ,Paper mill ,Pollution ,Refuse Disposal ,Cinder ,Plant Leaves ,Populus ,Agronomy ,engineering ,Environmental science ,Regression Analysis ,business ,Woody plant - Abstract
Science of The Total Environment, 447, ISSN:0048-9697, ISSN:1879-1026
- Published
- 2012
- Full Text
- View/download PDF
15. Performance of p+layer formed by B diffusion using boron paper
- Author
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Lei Jin, Chunzhi Ni, Qingzhu Wei, Wangyang Yang, Ye Jiang, Nannan Yang, and Honglie Shen
- Subjects
010302 applied physics ,Materials science ,Polymers and Plastics ,Silicon ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Semimetal ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Ion ,Biomaterials ,chemistry ,0103 physical sciences ,Wafer ,Diffusion (business) ,0210 nano-technology ,Boron ,Layer (electronics) ,Sheet resistance - Abstract
This paper presents a novel boron diffusion process using boron paper as the boron source to form a p+ layer. It was found that sheet resistance was invariable with changing the distance between boron paper and Si wafers, and diffusion uniformity was the best at a distance of 0.3 cm. Sheet resistance (Rs) decreased with increasing diffusion temperature, showing a value of 6.9 ?/ at 1050 ?C with a high diffusion uniformity of 99.173%. The junction depth increased from 195 nm to 517 nm with diffusion temperature raised from 900 ?C to 1050 ?C. The influence of diffusion time on the performance of B diffusion from boron paper was similar with that of temperature.
- Published
- 2018
16. Millennial Special Leading Papers on Ceramics in the 20th Century: the Best of JCerSJ Studies on the Conditions of Glass Formation
- Author
-
Minoru Imaoka
- Subjects
Glass structure ,Materials science ,Polymer science ,chemistry.chemical_element ,Mineralogy ,General Chemistry ,Material Design ,Condensed Matter Physics ,Glass forming ,Research objectives ,chemistry ,visual_art ,Materials Chemistry ,Ceramics and Composites ,visual_art.visual_art_medium ,Germanate ,Ceramic ,Boron ,Ternary operation - Abstract
This paper has the following key features. Systematic research on the many types of multicomponent (mainly ternary components) glass formation ranges, such as borate, silicate, germanate, vanadate and tellurite systems, revealed the conditions for multicomponent glass formation. Although the conditions for monocomponent glass formation identified by Zachariasen have been acknowledged since 1932, the conditions for multicomponent glass formation were not proposed at that time. Imaoka introduced general rules for the conditions of multicomponent glass formation on the basis of Zachariasen's rule. The adaptability of these conditions was confirmed by later research. Preciously, the glass formation probability of arbitrary compositions had only been judged by the melting method, but the application of general rules by Imaoka allowed predictions for glass formation possible without experimentation, and this allowed tremendous time savings during the planning of glass compositions.The establishment of multicomponent glass forming conditions clarified, to a certain extent, the relationship between the glass compositions and the glass structure. Therefore, the multicomponent glass forming conditions have been extremely useful in research on material design to predict the relationship between physical properties and the glass structure. Thus, it is now possible to target the research objectives more precisely and save considerable research time. Although not all commercial glass components can be judged by the conditions examined in this study, it is considered to be a reasonable reference for the discussion of commercial glass components.The above-mentioned features have contributed enormously to the research and technological development of glass.
- Published
- 2000
17. Macropolyhedral boron-containing cluster chemistry: A novel triple-cluster structural motif. Isolation and characterisation of contiguous twenty-vertex [(PPh3)4ClPd4B16H17(PPh3)2]1<fn id="fn1"><no>1</no>A cursive IUPAC nomenclature for compound 1 is μ-8,9-chloro-9″,5,7,9-tetrakis(triphenylphosphine)-arachno-6″,9″-dipalladadecaborano-{5″,6″,2″: 4′,1′,5′}-nido-1′,2′-dipalladapentaborano-{1′,2′,3′: 8,7,3}-nido-7,8,9-tripalladaundecaborane, and, for compound 2, 4,4-bis(triphenylphosphine)-arachno-4-palladanonaborane. This article was freely submitted for publication without royalty. By acceptance of this paper, the publisher and/or recipient acknowledges the right of the authors to retain non-exclusive, royalty-free license in and to any copyright covering this paper, along with the right to reproduce all or part of the copyrighted paper.</fn>
- Author
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Londesborough, Michael G.S., Kilner, Colin A., Thornton-Pett, Mark, and Kennedy, John D.
- Subjects
- *
BORON , *TOLUENE - Abstract
Twenty-vertex [(PPh3)4ClPd4B16H17(PPh3)] (1),1 from the thermolysis of [(PPh3)2PdB8H12] (2)1 in refluxing toluene solution, followed by CH2Cl2 extraction, has a core nido five-vertex {Pd2B3} unit that has opposing triangular faces in common with an arachno ten-vertex {Pd2B8} unit and a nido eleven-vertex {Pd3B8} unit. [Copyright &y& Elsevier]
- Published
- 2002
- Full Text
- View/download PDF
18. B-frame supported bimetallics. [(PMe2ph)2PtB9H11Ru(η6-isoPrC6H4Me)] and [(PMe2ph)2PtB9H9Ru(η6-isoPrC6H4Me)]; an interesting pair of electron-deficient nido and closo geometries1We are pleased to be able to dedicate this paper to Ken Wade, whose Rules have been instrumental and inspirational in the development of boron-containing cluster chemistry over the quarter century since their original formulation.1
- Author
-
Robert Greatrex, John D. Kennedy, Paul Cooke, Young-hee Kim, and Mark Thornton-Pett
- Subjects
Inorganic Chemistry ,Crystallography ,Chemistry ,Organic Chemistry ,Materials Chemistry ,Cluster (physics) ,chemistry.chemical_element ,Electron ,Physical and Theoretical Chemistry ,Boron ,Biochemistry - Abstract
[7,7-(PMe 2 Ph) 2 -9-( η 6 - iso PrC 6 H 4 Me)-7,9-PtRuB 9 H 11 ] has a formal closo Wadian cluster-electron count, but a nido geometry, whereas [1-( η 6 - iso PrC 6 H 4 Me)-4,4-(PMe 2 Ph) 2 -1-4-RuPtB 9 H 9 ], which does have a closo geometry, has a formal sub- closo cluster electron count; both compounds are formed in the reaction between [6-( η 6 - iso PrC 6 H 4 Me)- nido -6 RuB 9 H 13 ], KH and [PtCl 2 (PMe 2 Ph) 2 ].
- Published
- 1998
19. Properties of Paper Treated with Starch-Borate Complex Colloidal Solution
- Author
-
Ryoichi Murakami
- Subjects
chemistry.chemical_compound ,Chemical engineering ,Chemistry ,Starch ,chemistry.chemical_element ,Boron ,Colloidal Solution - Published
- 1992
20. Ultrasensitive Detection of Tetracycline Using Boron and Nitrogen Co-Doped Graphene Quantum Dots from Natural Carbon Source as the Paper-Based Nanosensing Probe in Difference Matrices.
- Author
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Tran, Hai Linh, Darmanto, Win, and Doong, Ruey-An
- Subjects
- *
QUANTUM dots , *TETRACYCLINES , *TETRACYCLINE , *NITROGEN , *ORGANIC compounds , *GRAPHENE , *BORON , *PASSION fruit - Abstract
Herein, the boron and nitrogen co-doped 0-dimensional graphene quantum dots (B,N-GQDs) with high quantum yield (QY) were synthesized via microwave-assisted hydrothermal method at 170 °C for 20 min using fresh passion fruit juice and boric acid as the starting materials. The 3–6 layers of B,N-GQDs with mean particle size of 9 ± 1 nm were then used for ultra-sensitive and selective detection of tetracycline in aqueous and biological media. The hybridization of boron and nitrogen atoms into the GQD structures increases the intensity of electronegative, resulting in the enhancement of QY to 50 ± 1%. The B,N-GQDs show their excellent analytical performance on tetracycline determination after 2 min of reaction under an optimal condition at pH 5. The linear range of 0.04–70 µM and with limits of detection (LOD) of 1 nM in phosphate buffer saline (PBS), 1.9 nM in urine and 2.2 nM in human serum are obtained. Moreover, the high selectivity of tetracycline by B,N-GQDs over the other 23 interferences is observed. The π-π interaction and electron donor-acceptor principle play pivotal roles in enhancing the ultra-sensitivity and selectivity of B,N-GQDs toward TC detection. Moreover, the B, N-GQD based paper nanosensor exhibits an excellent analytical performance on visual detection of 0.1–30 µM TC in human serum. Results of this study clearly indicate the feasibility of synthesis of B,N-GQDs derived from passion fruit juice for ultrasensitive tetracycline detection, which can open an avenue to use natural products for the preparation of environmentally benign and biocompatible carbon nanomaterials for highly sensitive detection of drugs, antibiotics, organic compounds and biomarkers. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
21. Boron Compounds-Added Kraft Pulping from Scots Pine; [Kraft celuloza od borovine s dodatkom spojeva bora]
- Author
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Kuştaş, Süleyman and Gülsoy, Sezgin Koray
- Subjects
Additives ,Boron Compounds ,Kraft Pulping ,Paper Properties ,Pinus Sylvestris ,Pulp Properties ,Sodium Borohydride ,Yield ,Paper properties ,Pinus sylvestris ,Pinus sylvestris (L.) ,Pinus sylvestris L ,Pulp and paper ,Pulp properties ,Pulp strength ,Pulp yields ,Scots pine ,Total yield ,additive ,boron ,colemanite ,pine ,pulp and paper industry ,wood ,Kraft pulp - Abstract
In this study, effects of KBH4 (PB), NaBH4 (SB), Etibor-48 (E48), Etidot-67 (E67), and colemanite (Col) on kraft pulp and paper properties of Scots pine (Pinus sylvestris L.) wood were evaluated. The control and boron compound-added kraft pulps were obtained under constant cooking conditions. The boron compounds were used as digester additives in different ratios (2 % and 4 %). The addition of boron compounds to kraft cooking liquor resulted in increases screened and total yield of pulps. The highest screened yield (52.05 %) and total yield (55.09 %) were obtained from PB-4 pulp. The lowest reject ratio (0.61 %) and kappa number (34.60) were determined from PB-2 pulp. Furthermore, the highest tensile properties of handsheets were obtained from E67-4 pulp. Also, E48-4 pulp had the highest burst index and tear index values. E48, E67, and Col are cheaper than PB and SB. From these boron compounds, pulps with relatively low pulp yield but stronger can be obtained. © 2023 by the author(s).
- Published
- 2023
22. Enhanced boron removal via seed-induced crystal growth of barium perborate in sequential fluidized-bed crystallization.
- Author
-
Lin JY and Huang YH
- Subjects
- Borates chemistry, Chemical Precipitation, Water Pollutants, Chemical chemistry, Boron chemistry, Crystallization, Barium chemistry
- Abstract
Chemical oxo-precipitation (COP) is an enhanced precipitation method for boron removal with the conversion of boric acid to perborate anions. When using barium-based precipitant, the boron can be effectively precipitated as barium perborates (BaPBs). The phase transformation of BaPBs from amorphous (A-BaPB, Ba(B(OH)
3 OOH)2 ) to crystalline (C-BaPB, BaB2 (OO)2 (OH)4 ) form is crucial for effective boron removal. However, scaling up this phase transformation of BaPBs is hindered by poor diffusion. This study aims to promote the growth of C-BaPB through seed-induced crystal growth, eliminating the need for phase transformation. By examining the relationship between crystal growth rate and supersaturation, surface spiral growth was identified as the rate-limiting step of the growth of micron-sized seeds near pHpzc . To enable continuous crystal growth, granular seeds of C-BaPB were prepared and employed as the medium for fluidized-bed crystallization (FBC). The system reached steady state 3 hydraulic retention times, achieving 90% boron removal. The effect of surface loading, ionic strength, and dosages on steady-state crystal growth rate was studied, revealing a shift of the rate-limiting step in FBC to diffusion. Lastly, the system that constituted of two FBCs in-series for sequential crystallization of A-BaPB and C-BaPB was demonstrated. The integrated system provided 97.8% of boron removal from synthetic wastewater containing 500 mg-B/L, with 92.3% of boron crystallized on the granular seeds of BaPBs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)- Published
- 2024
- Full Text
- View/download PDF
23. Comprehensive risk assessment and interactions of fluoride and boron ions in the water-sediments interface: The Red Sea, Egypt.
- Author
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El-Said GF, El Zokm GM, El-Sayed AAM, and Soliman NF
- Subjects
- Risk Assessment, Egypt, Humans, Indian Ocean, Ions, Adult, Boron analysis, Boron chemistry, Water Pollutants, Chemical analysis, Seawater chemistry, Fluorides analysis, Geologic Sediments chemistry, Environmental Monitoring
- Abstract
This study presents a baseline evaluation of the distribution, human and ecotoxicological risk, and the potential interactions of fluoride and boron in the water-sediment interface in 25 locations from incredible Red Sea tourist destinations. Results showed comparable levels of B and F in the water and sediments with previous literature. Significant positive correlation was found between B and F (r = 0.57; P<0.01). Based on the sediment/liquid partition coefficient (K
d ), F is more likely to be released from the sediment into seawater (logKd < 3) than B (3< logKd < 4). pH and alkalinity may affect water-sediment interactions of B and F, respectively, while SO4 2- and Cl- ions had no significant effect on adsorption ability of F and B. The majority of minerals had average saturation Index (SI) > 1 referring to the over saturation of seawater with these minerals and their inability to dissolve. The formation of CF, FAP, and CFAP may be related to the high correlation between Fw (r = 0.928, P< 0.01; r = 0.527, P< 0.01; r = 0.608, P< 0.01) and Bw (r = 0.38, P< 0.05; r = 0.38, P< 0.05; r = 0.397, P< 0.05). Total hazard quotient (THQ) for children and adults were <1, revealing no health risks from exposure to B and F through ingestion and skin contact while swimming. The risk characterization ratio; RCRmix(MEC/PNEC) showed high short-term risks to aquatic organisms. Further investigations might emphasis on emerging mitigation strategies to address these concerns., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)- Published
- 2024
- Full Text
- View/download PDF
24. Driving the Emission Towards Blue by Controlling the HOMO‐LUMO Energy Gap in BF 2 ‐Functionalized 2‐(Imidazo[1,5‐ a ]pyridin‐3‐yl)phenols
- Author
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Colombo, Gioele, Attilio Ardizzoia, G., Furrer, Julien, Therrien, Bruno, and Brenna, Stefano
- Subjects
Boron Compounds ,Models, Molecular ,Band gap ,Substituent ,Catalysis ,chemistry.chemical_compound ,symbols.namesake ,Phenols ,Stokes shift ,540 Chemistry ,HOMO/LUMO ,Density Functional Theory ,blue emission ,Full Paper ,HOMO-LUMO gap ,Ligand ,Chemistry ,Organic Chemistry ,boron ,fluorescence ,TD-DFT ,General Chemistry ,Full Papers ,Fluorescence ,Crystallography ,Atomic electron transition ,symbols ,Quantum Theory ,Density functional theory - Abstract
Several boron compounds with 2‐(imidazo[1,5‐a]pyridin‐3‐yl)phenols, differentiated by the nature of the substituent (R) in the para position of the hydroxy group, have been synthesized and thoroughly characterized both in solution (1H, 13C, 11B, 19F NMR) and in the solid state (X‐ray). All derivatives displayed attractive photophysical properties like very high Stokes shift, high fluorescence quantum yields and a good photostability in solution. Time‐Dependent Density Functional Theory (TD‐DFT) calculations allowed to define the main electronic transitions as intra ligand transitions (1ILT), which was corroborated by the Natural Transition Orbitals (NTOs) shapes. The homo‐lumo energy gap was correlated to the electronic properties of the substituent R on the phenolic ring, as quantified by its σp Hammett constant., Blue emissive materials: boron containing fluorescent compounds have been prepared starting from imidazo[1,5‐a]pyridine phenols. Large Stokes shift, high absolute quantum yields and good photostability are observed in solution. TD‐DFT calculations allowed to find a linear correlation between the HOMO‐LUMO energy gap of these compounds and the Hammett constants of substituents R para to the hydroxyl group of the phenols.
- Published
- 2021
25. Rethinking Borole Cycloaddition Reactivity
- Author
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Krzysztof Radacki, Theresa Dellermann, Ivo Krummenacher, Todd B. Marder, Guillaume Bélanger-Chabot, Tom E. Stennett, Anna Rempel, Anna Lamprecht, Florian Rauch, Valerie Paprocki, Tobias Brückner, Xueying Guo, Felix Lindl, Holger Braunschweig, and Zhenyang Lin
- Subjects
Pericyclic reaction ,Substituent ,010402 general chemistry ,01 natural sciences ,Catalysis ,isomerization ,chemistry.chemical_compound ,pericyclic reaction ,Computational chemistry ,Reactivity (chemistry) ,Borole ,Boron ,Bicyclic molecule ,Full Paper ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,General Chemistry ,Full Papers ,Small molecule ,computational chemistry ,Cycloaddition ,0104 chemical sciences ,isomer ,ddc:546 ,Isomerization - Abstract
Boroles are attracting broad interest for their myriad and diverse applications, including in synthesis, small molecule activation and functional materials. Their properties and reactivity are closely linked to the cyclic conjugated diene system, which has been shown to participate in cycloaddition reactions, such as the Diels‐Alder reaction with alkynes. The reaction steps leading to boranorbornadienes, borepins and tricyclic boracyclohexenes from the thermal reaction of boroles with alkynes are seemingly well understood as judged from the literature. Herein, we question the long‐established mechanistic picture of pericyclic rearrangements by demonstrating that seven‐membered borepins (i. e., heptaphenylborepin and two derivatives substituted with a thienyl and chloride substituent on boron) exist in a dynamic equilibrium with the corresponding bicyclic boranorbornadienes, the direct Diels‐Alder products, but are not isolable products from the reactions. Heating gradually converts the isomeric mixtures into fluorescent tricyclic boracyclohexenes, the most stable isomers in the series. Results from mechanistic DFT calculations reveal that the tricyclic compounds derive from the boranorbornadienes and not the borepins, which were previously believed to be intermediates in purely pericyclic processes., New insights into the reactivity of perarylated boroles toward alkynes have been derived from both experimental and computational studies. It is shown that borepins (the formal alkyne insertion products) can readily isomerize to the thermodynamically more favorable boranorbornadienes (the formal Diels‐Alder products), thus obscuring the mechanism of product formation (see Figure). In addition, the fluorescent nature of the tricyclic boracyclohexenes, the most stable isomers of the addition reactions, has been investigated by absorption and emission spectroscopy.
- Published
- 2021
26. Ni‐Catalyzed Borylation of Aryl Sulfoxides
- Author
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Mingming Huang, Todd B. Marder, Zhu Wu, Udo Radius, Alexandra Friedrich, Xiaoling Luo, Johannes Krebs, and Stephen A. Westcott
- Subjects
Substituent ,010402 general chemistry ,01 natural sciences ,Medicinal chemistry ,Borylation ,Catalysis ,chemistry.chemical_compound ,nickel ,borylation ,cross-coupling ,N-heterocyclic carbenes ,Boron ,Trifluoromethyl ,Full Paper ,010405 organic chemistry ,Aryl ,Organic Chemistry ,Regioselectivity ,Sulfoxide ,General Chemistry ,Full Papers ,Oxidative addition ,0104 chemical sciences ,chemistry ,ddc:546 ,Carbene - Abstract
A nickel/N‐heterocyclic carbene (NHC) catalytic system has been developed for the borylation of aryl sulfoxides with B2(neop)2 (neop=neopentyl glycolato). A wide range of aryl sulfoxides with different electronic and steric properties were converted into the corresponding arylboronic esters in good yields. The regioselective borylation of unsymmetric diaryl sulfoxides was also feasible leading to borylation of the sterically less encumbered aryl substituent. Competition experiments demonstrated that an electron‐deficient aryl moiety reacts preferentially. The origin of the selectivity in the Ni‐catalyzed borylation of electronically biased unsymmetrical diaryl sulfoxide lies in the oxidative addition step of the catalytic cycle, as oxidative addition of methoxyphenyl 4‐(trifluoromethyl)phenyl sulfoxide to the Ni(0) complex occurs selectively to give the structurally characterized complex trans‐[Ni(ICy)2(4‐CF3‐C6H4){(SO)‐4‐MeO‐C6H4}] 4. For complex 5, the isomer trans‐[Ni(ICy)2(C6H5)(OSC6H5)] 5‐I was structurally characterized in which the phenyl sulfinyl ligand is bound via the oxygen atom to nickel. In solution, the complex trans‐[Ni(ICy)2(C6H5)(OSC6H5)] 5‐I is in equilibrium with the S‐bonded isomer trans‐[Ni(ICy)2(C6H5)(SOC6H5)] 5, as shown by NMR spectroscopy. DFT calculations reveal that these isomers are separated by a mere 0.3 kJ/mol (M06/def2‐TZVP‐level of theory) and connected via a transition state trans‐[Ni(ICy)2(C6H5)(η2‐{SO}‐C6H5)], which lies only 10.8 kcal/mol above 5., A nickel/N‐heterocyclic carbene (NHC) catalytic system has been developed for the borylation of aryl sulfoxides with B2(neop)2 (neop=neopentyl glycolato). A wide range of aryl sulfoxides with different electronic and steric properties were converted into the corresponding arylboronic esters in good yields. Elucidation of key mechanistic features of this newly developed reaction led to the identification of fully characterized nickel intermediates.
- Published
- 2021
27. Preclinical and histological study of boron-containing compounds hydrogels on experimental model of periodontal disease
- Author
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Melania Olimpia Cojocaru, Horia Octavian Manolea, Mihai Popescu, Ion Romulus Scorei, Daniel Alin Olimid, Ioana Mitruţ, Andrei Biţă, and George Dan Mogoşanu
- Subjects
Embryology ,Pathology ,medicine.medical_specialty ,experimental model ,periodontal disease ,Alveolar Bone Loss ,Inflammation ,Pathology and Forensic Medicine ,Periodontal disease ,Boron containing ,Calcium Fructoborate ,medicine ,Animals ,Rats, Wistar ,Boron ,Periodontitis ,Original Paper ,Experimental model ,business.industry ,Soft tissue ,Hydrogels ,Cell Biology ,General Medicine ,Models, Theoretical ,medicine.disease ,Oral tissue ,Rats ,inflammation ,Self-healing hydrogels ,ligature ,Boric Acid ,medicine.symptom ,business ,Developmental Biology - Abstract
Periodontitis is a disease that affects a wide group of people, and there has been an increased interest in the research of finding useful materials that help reduce inflammation and the further loss of tissue. In this study, we have tested a boron-containing compound (BCC) Calcium Fructoborate (CaFB) and Boric Acid (BA) hydrogels on the gingival level on Wistar rats. First, we have induced the periodontal disease at the lower incisors, we have applied the hydrogels and after a week, we have euthanized the rats. Next, the oral soft tissue reaction was clinically and then histologically investigated. Our study has shown good clinical response of the oral tissue, and we have noticed lower levels of inflammation on the experimental groups treated with the BCCs hydrogels. Despite the generally good response of the biological structures to the presence of BA and CaFB on periodontal level, more scientifically proved information is needed to obtain the desired biological responses in all clinical situations.
- Published
- 2021
28. CO‐Induced Dinitrogen Fixation and Cleavage Mediated by Boron
- Author
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Guanjun Wang, Sudip Pan, Mingfei Zhou, Guohai Deng, Lili Zhao, Gernot Frenking, and Xuelin Dong
- Subjects
chemistry.chemical_element ,Infrared spectroscopy ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Catalysis ,bonding analysis ,chemistry.chemical_compound ,Neon ,Molecule ,Boron ,Full Paper ,010405 organic chemistry ,Ligand ,Organic Chemistry ,Matrix isolation ,matrix isolation ,N2 fixation and activation ,General Chemistry ,Full Papers ,N2 Fixation ,Nitrogen ,0104 chemical sciences ,chemistry ,IR spectroscopy ,boron ,Carbon monoxide - Abstract
The boron atoms react with carbon monoxide and dinitrogen forming the end‐on bonded NNBCO complex in solid neon or in nitrogen matrices. The NNBCO complex rearranges to the (η 2‐N2)BCO isomer with a more activated side‐on bonded dinitrogen ligand upon visible light excitation. (η 2‐N2)BCO and its weakly CO‐coordinated complexes further isomerize to the NBNCO and B(NCO)2 molecules with N−N bond being completely cleaved under UV light irradiation. The geometries, energies and vibrational spectra of the molecules are calculated with quantum chemical methods and the electronic structures are analyzed with charge‐ and energy‐partitioning methods., CO‐induced dinitrogen fixation and cleavage mediated by boron atoms is reported. The experimental and theoretical results show that the N≡N activation processes proceed with the initial formation of an end‐on bonded NNBCO complex, which rearranges to the NBNCO and B(NCO)2 isocyanate complexes via a side‐on bonded (η2‐N2)BCO intermediate. The geometries, energies and vibrational spectra of the molecules are calculated with quantum chemical methods and the electronic structures are analyzed with charge‐ and energy‐partitioning methods.
- Published
- 2020
29. Synthesis and Coordination Behavior of a New Hybrid Bidentate Ligand with Phosphine and Silylene Donors
- Author
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Herbert W. Roesky, Regine Herbst-Irmer, Annika Münch, Christina M. Legendre, Mohd Nazish, Mujahuddin M. Siddiqui, Samir Kumar Sarkar, and Dietmar Stalke
- Subjects
Denticity ,chemistry.chemical_element ,Ionic bonding ,010402 general chemistry ,01 natural sciences ,Medicinal chemistry ,Catalysis ,phosphane ,chemistry.chemical_compound ,Chelation ,P/Si Ligands ,Full Paper ,010405 organic chemistry ,Ligand ,aluminium ,Organic Chemistry ,Silylene ,General Chemistry ,Nuclear magnetic resonance spectroscopy ,Full Papers ,Copper ,0104 chemical sciences ,3. Good health ,silylene ,chemistry ,copper ,boron ,Phosphine - Abstract
This work describes the synthesis and coordination behavior of a new mixed‐donor ligand PhC(NtBu)2SiC6H4PPh2 (1) containing both silylene and phosphine donor sites. Ligand 1 was synthesized from a reaction of ortho‐lithiated diphenylphosphinobenzene (LiC6H4PPh2) with chlorosilylene (PhC(NtBu)2SiCl). Treatment of 1 with Se and GeCl2 resulted in SiIV compounds 2 and 3 by selective oxidation of the silylene donor. This strong σ‐donor ligand induces dissociation of CuCl and PhBCl2 leading to formation of ionic complexes 4 and 5 respectively. The reaction of 1 with ZnCl2 and AlCl3 resulted in the formation of chelate complexes 5 and 7, respectively, while treatment with EtAlCl2 and GaCl3 forms monodentate complexes 8 and 9. X‐ray analysis of 4 showed that the copper is in the spiro center of the two five‐membered rings. Moreover, the copper(I)chloride has not been oxidized but dissociates to Cu+ and [CuCl2]−. All the compounds are well characterized by mass spectrometry, elemental analysis, NMR spectroscopy, and single‐crystal X‐ray diffraction studies., A ligand with different Lewis base donor sites of phosphorus(III) and silicon(II). The ligands are arranged in 1,2‐position at the benzene ring to generate mainly five‐membered ring compounds containing a metal atom. The exceptions of the compounds show clearly that the metal is preferentially coordinated to the silylene atom rather than to the phosphane site of the ligand.
- Published
- 2020
30. Nature and Strength of Lewis Acid/Base Interaction in Boron and Nitrogen Trihalides
- Author
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Daniela Rodrigues Silva, Matheus P. Freitas, Lucas de Azevedo Santos, Trevor A. Hamlin, Célia Fonseca Guerra, Theoretical Chemistry, and AIMMS
- Subjects
Base (chemistry) ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Lewis acid-base pairs ,Activation strain analysis ,Adduct ,Very Important Paper ,Molecule ,Lewis acids and bases ,SDG 7 - Affordable and Clean Energy ,Bond energy ,Boron ,chemistry.chemical_classification ,Full Paper ,010405 organic chemistry ,Bond strength ,Organic Chemistry ,General Chemistry ,Full Papers ,Nitrogen ,0104 chemical sciences ,Crystallography ,Density functional calculations ,Energy decomposition analysis ,chemistry - Abstract
We have quantum chemically investigated the bonding between archetypical Lewis acids and bases. Our state‐of‐the‐art computations on the X3B−NY3 Lewis pairs have revealed the origin behind the systematic increase in B−N bond strength as X and Y are varied from F to Cl, Br, I, H. For H3B−NY3, the bonding trend is driven by the commonly accepted mechanism of donor−acceptor [HOMO(base)−LUMO(acid)] interaction. Interestingly, for X3B−NH3, the bonding mechanism is determined by the energy required to deform the BX3 to the pyramidal geometry it adopts in the adduct. Thus, Lewis acids that can more easily pyramidalize form stronger bonds with Lewis bases. The decrease in the strain energy of pyramidalization on going from BF3 to BI3 is directly caused by the weakening of the B−X bond strength, which stems primarily from the bonding in the plane of the molecule (σ‐like) and not in the π system, at variance with the currently accepted mechanism., That's strainful! The stability of Lewis pairs involving boron trihalides and ammonia is driven by the energy required to deform the Lewis acids upon complexation, while the stability of Lewis pairs between borane and nitrogen trihalides is determined by the strength of orbital interactions.
- Published
- 2020
31. Towards the enhancement of nuclear reactor safety: Physical phenomena involved in the measurement accuracy of boron concentration online monitoring systems.
- Author
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Tabti, Nouhaila, Sari, Adrien, and Tromson, Dominique
- Subjects
NUCLEAR reactors ,BORON ,BORIC acid ,POWER distribution in nuclear reactors ,MONTE Carlo method - Abstract
In Pressurized Water Reactors (PWRs), boron10 (
10 B) is added to the primary fluid as boric acid to regulate criticality and power distribution within the core. Indeed,10 B possesses a significant neutron absorption cross-section of approximately 3845 barns for thermal neutron energy (around 25.3 meV). Thus, under certain circumstances, even a slight variation in boron concentration could lead to criticality issues. This paper addresses the problems regarding the accuracy and real-time measurement of Boron Concentration Online Monitoring Systems (BCOMS) in PWRs. First, the paper focuses on presenting BCOMS's key performance and qualification criteria to ensure a real-time, accurate response during normal operation, operational transients, and accidental events. Then, we evaluate the influence of different dimensioning parameters on the overall measuring performance through Monte Carlo simulations using the MCNP6.2 code. Finally, we investigate, combining theoretical knowledge and simulation results, the physical phenomena involved in the measurement accuracy of BCOMS. This analytical approach not only fosters a deeper comprehension of the underlying phenomena but also facilitates the identification of potential areas for improving measurement accuracy, thereby enhancing the safety of nuclear reactors. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
32. Highly Stable, Readily Reducible, Fluorescent, Trifluoromethylated 9‐Borafluorenes
- Author
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Ivo Krummenacher, Maik Finze, Todd B. Marder, Alexandra Friedrich, Daniel Sieh, Holger Braunschweig, Sonja Fuchs, and Florian Rauch
- Subjects
Proton ,Dibenzoborole ,010402 general chemistry ,01 natural sciences ,Catalysis ,law.invention ,chemistry.chemical_compound ,law ,Borafluorenes | Very Important Paper ,Moiety ,Electron paramagnetic resonance ,heterocycles ,Trifluoromethyl ,Full Paper ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,General Chemistry ,Full Papers ,Fluorescence ,0104 chemical sciences ,borafluorenes ,Crystallography ,Excited state ,ddc:540 ,fluorescence ,boron ,EPR spectroscopy - Abstract
Three different perfluoroalkylated borafluorenes (F Bf) were prepared and their electronic and photophysical properties were investigated. The systems have four trifluoromethyl moieties on the borafluorene moiety as well as two trifluoromethyl groups at the ortho positions of their exo‐aryl moieties. They differ with regard to the para substituents on their exo‐aryl moieties, being a proton (F XylFBf, FXyl: 2,6‐bis(trifluoromethyl)phenyl), a trifluoromethyl group (F MesFBf, FMes: 2,4,6‐tris(trifluoromethyl)phenyl) or a dimethylamino group (p ‐NMe2‐FXylFBf, p‐NMe2‐FXyl: 4‐(dimethylamino)‐2,6‐bis(trifluoromethyl)phenyl), respectively. All derivatives exhibit extraordinarily low reduction potentials, comparable to those of perylenediimides. The most electron‐deficient derivative F MesFBf was also chemically reduced and its radical anion isolated and characterized. Furthermore, all compounds exhibit very long fluorescent lifetimes of about 250 ns up to 1.6 μs; however, the underlying mechanisms responsible for this differ. The donor‐substituted derivative p ‐NMe2‐FXylFBf exhibits thermally activated delayed fluorescence (TADF) from a charge‐transfer (CT) state, whereas the F MesFBf and F XylFBf borafluorenes exhibit only weakly allowed locally excited (LE) transitions due to their symmetry and low transition‐dipole moments., Having your cake and eating it too: Functionalization of 9‐borafluorenes with trifluoromethyl groups makes them exceptionally easy to reduce while maintaining excellent stability towards hydrolysis. The systems also exhibit long‐lived fluorescence or thermally activated delayed fluorescence (TADF) depending on the exo‐aryl para‐substituent.
- Published
- 2020
33. Unusual Nitrene Oxidation Product Formation by Metathesis Involving the Dioxygen O−O and Borylnitrene B−N Bonds
- Author
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Virinder Bhagat, Julia Schumann, and Holger F. Bettinger
- Subjects
Exothermic reaction ,Reaction mechanism ,Full Paper ,010405 organic chemistry ,Chemistry ,Nitrene ,Radical ,Organic Chemistry ,Infrared spectroscopy ,General Chemistry ,Full Papers ,radicals ,010402 general chemistry ,Photochemistry ,Metathesis ,01 natural sciences ,Quantum chemistry ,Catalysis ,0104 chemical sciences ,nitrenes ,density functional calculations ,Reaction Mechanisms ,boron ,Isomerization - Abstract
The reaction of dioxygen with nitrenes can have significant energy barriers, although both reactants are triplet diradicals and the formation of nitroso‐O‐oxides is spin‐allowed. By means of matrix‐isolation infrared spectroscopy in solid argon, nitrogen, and neon, and through high‐level computational quantum chemistry, it is shown herein that a 3‐nitreno‐1,3,2‐benzodioxaborole CatBN (Cat=catecholato) reacts with dioxygen under cryogenic conditions thermally at temperatures as low as 7 K to produce two distinct products, an anti‐nitroso‐O‐oxide and a nitritoborane CatBONO. The computed barriers for the formation of nitroso‐O‐oxide isomers are very low. Whereas anti‐nitroso‐O‐oxide is kinetically trapped, its bisected isomer has a very low barrier for metathesis, yielding the CatBO+NO radicals in a strongly exothermic reaction; these radicals can combine under matrix‐isolation conditions to give nitritoborane CatBONO. The trapped isomer, anti‐nitroso‐O‐oxide, can form the nitritoborane CatBONO only after photoexcitation, possibly involving isomerization to the bisected isomer of anti‐nitroso‐O‐oxide., Overcoming barriers: The reaction of dioxygen with nitrenes can have significant energy barriers. The reaction mechanism of borylnitrene 1 is investigated through matrix‐isolation infrared spectroscopy and high‐level computational quantum chemistry. Borylnitrene 1 reacts with dioxygen to form nitritoborane 3 a via nitroso‐O‐oxide isomer 2 c. Nitroso‐O‐oxide isomer 2 a is stable towards thermal reaction to 3 a, but dyotropic rearrangement can be achieved photochemically.
- Published
- 2020
34. Effect of boron fertilization on productivity and sustainability of rice-wheat cropping system in Tarai region, North-West India.
- Author
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Pachauri SP, Shukla AK, Srivastava PC, Behara SK, Butail NP, Thakur P, Thakur P, Anjali, Sharma M, Sharma PK, Sahu A, and Kumar P
- Subjects
- India, Soil chemistry, Oryza growth & development, Boron, Triticum growth & development, Fertilizers, Agriculture methods, Crops, Agricultural growth & development
- Abstract
Extensive global dependency on rice and wheat crops has necessitated the adoption of intensive cultivation practices, thereby compelling to closely monitor the potential yield-limiting factors, among which, boron (B) deficiency stands out to be a prime concern. The present study explores the effects of B fertilization strategies within the Rice-Wheat Cropping System (RWCS) in the Tarai region of North-West India. A comprehensive six-year field experiment was conducted (2013-2019) at G.B. Pant University of Agriculture and Technology, Uttarakhand, India. The experiment tested graded B doses (0.5, 1.0, 1.5, and 2.0 kg ha
-1 ) at varied frequencies (single, alternate, and annual) in a factorial design. The study revealed significant impacts of alternate B application at 1.5 kg ha-1 on crop yields and the Sustainable Yield Index (SYI). The System Rice Equivalent Yield (SREY) exhibited an increase of 6.7% with B supplementation over B-deprived plots, highlighting the pivotal role of B fertilizer in enhancing productivity within the RWCS. The economic optimum B dose was found to be 1.422 kg ha-1 using a linear plus plateau model, resulting in a calculated annual SREY of 9.73 t ha-1 when applied alternately to the cropping system. Continuous application and higher B rates demonstrated substantial increases in various B fractions, while the mobility factor remained within 10%, depicting safe ecological limits. The distribution of fractions in B-treated plots on average followed the order: residual B > organically-bound B > oxide bound B > specifically adsorbed B > readily soluble B. Similarities in the distribution patterns of B fractions between B-treated plots and the control indicated potential influence of biotic or abiotic processes on B fraction dynamics, even in the absence of external B application. To sum up, B application in alternate years at 1.5 kg ha-1 was most sustainable in enhancing the SREY, SYI, available soil B, and B fractions and lowering the environmental hazards., Competing Interests: Declaration of competing interest The author(s) declared no potential conflict of interest that could have appeared to influence the work reported in the present paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)- Published
- 2024
- Full Text
- View/download PDF
35. Quantum chemical framework for tailoring N/B doped phenalene derivatives to achieve high performance nonlinear optical materials.
- Author
-
urRehman S, Fatima S, Muhammad S, Bibi S, Munawar KS, Al-Sehemi AG, Chaudhry AR, and Adnan M
- Subjects
- Anisotropy, Electronics, Nitrogen, Boron, Phenalenes
- Abstract
Nonlinear optical (NLO) response materials are among the smartest materials of the era and are employed to modulate the phase and frequency of the laser. The present study presents a quantum chemical framework for tailoring nitrogen/boron doped derivatives of Dihydrodibenzo [de,op]pentacene through terminal and central core modifications. The derivatives of these compounds have been designed by introducing various π-conjugated connectors as well as B/N heteroatoms in the phenalene rings. Density functional theory (DFT) methods are used to optimize the ground state molecular geometries of designed compounds, represented as 1 to 4 (phenalene derivatives) and 1-BN to 4-BN (B/N doped phenalene derivatives) at the M06-2X/6-311G* level of theory. The highest value of 116.9 × 10
-24 esu and 240.2 × 10-24 esu for isotropic and anisotropic linear polarizability is shown by compound 4. Among the designed compounds, 4-BN has achieved the highest γ amplitude of 1858 × 10-36 esu owing to its unique molecular structural design. Further analysis of electronic parameters, such as electron density difference (EDD) maps, the density of states, electrostatic potentials, transition density matrix (TDM) analysis, and frontier molecular orbitals analysis (FMOs), demonstrated the more effective intramolecular charge transfer (ICT) for the best compounds, resulting in a good NLO response. The compounds were also analyzed for their potential in photovoltaic applications based on factors such as open circuit voltage values determined to be between (0.14 eV and 1.82 eV), and light harvesting efficiency (0.425-0.909)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)- Published
- 2024
- Full Text
- View/download PDF
36. Tunability of electronic and thermoelectric properties of hexagonal boron nitride with carbon impurities under magnetic field: Tight binding investigation.
- Author
-
Behzad S and Chegel R
- Subjects
- Carbon, Electronics, Nitrogen, Boron, Magnetic Fields, Boron Compounds
- Abstract
Utilizing the Kubo-Greenwood formula, Tight Binding calculations were employed to examine the electronic and thermoelectric properties of hexagonal boron nitride (h-BN) with carbon impurity instead of boron, nitrogen and pairs boron-nitrogen. The electronic properties of the pristine monolayer BN are markedly impacted by the introduction of carbon dopants and its band gap reduction is directly correlated with the concentration of carbon impurities. The electronic properties of doped h-BN are influenced by the presence of a magnetic field, leading to subband separation and band gap narrowing, independent of the impurity types. The thermal conductivity and magnetic susceptibility of the C
BN -doped monolayer BN structure are higher than those of the BC and NC doped h-BN structures and for all structures, their properties have a strong dependence on the magnetic field. The Lorenz Number for all structures has peak at the TM temperature which shifts to a lower temperature as the impurity concentration decreases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)- Published
- 2024
- Full Text
- View/download PDF
37. 环保型钆硼柔性热中子吸收材料特性研究.
- Author
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王 琦, 郭晓林, 尹进南, 王晓娟, 原 林, 王博宇, 方青龙, 韩小祥, 仇天祎, and 刘 洋
- Abstract
Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
38. Accurate Boron Determination in Tourmaline by Inductively Coupled Plasma Mass Spectrometry: An Insight into the Boron–Mannitol Complex-Based Wet Acid Digestion Method.
- Author
-
Tan, Xijuan, Feng, Yonggang, Zhou, Ruili, Wang, Denghong, Liang, Ting, and Wang, Yan
- Subjects
INDUCTIVELY coupled plasma mass spectrometry ,TOURMALINE ,BORON - Abstract
Tourmaline, a boron-bearing mineral, has been extensively applied as a geothermometer, provenance indicator, and fluid-composition recorder in geological studies. In this paper, the decomposition capability of an HF-HNO
3 –mannitol mixture for a tourmaline sample was investigated in detail for the first time, and a wet acid digestion method based on the boron–mannitol complex for accurate boron determination in tourmaline by inductively coupled plasma mass spectrometry (ICP-MS) was proposed. With a digestion temperature of 140 °C, tourmaline samples of 25 mg (±0.5 mg) can be completely decomposed by a ternary mixture, which consisted of 0.6 mL of HF, 0.6 mL of HNO3 , and 0.7 mL of 2% mannitol (wt.), via a continuous heating treatment of 36 h. Following gentle evaporation at 100 °C, the sample residues were re-dissolved using 2 mL of 40% HNO3 solution (wt.) and diluted to about 2.0 × 105 -fold by a two-step method using 2% HNO3 solution (wt.). The boron contents in a batch of parallel tourmaline samples were then determined by ICP-MS, and results showed that the boron concentration levels were in a range of 3.20–3.44% with determination RSDs less than 4.0% (n = 5). It was found that the boron concentrations obtained at the mass of10 B were comparable with results from the measurements at the mass of11 B. This revealed that the usage of 2% mannitol with a quantity as high as 0.7 mL in this developed approach did not exhibit significant effect on the quantification accuracy of boron at the mass of11 B. It was also found that the processes including fluoride-forming prevention and fluoride decomposition deteriorated the boron-reserving efficiency of mannitol for tourmaline, causing the averaged boron contents to vary from 2.25% to 3.57% (n = 5). Furthermore, the stability of the boron–mannitol complex under 185 °C by applying the laboratory high pressure-closed digestion method was evaluated, which showed that there existed a 60.36% loss of boron compared to that under 140 °C by using this proposed approach. For this ternary mixture, the tourmaline decomposing efficiency was found to be weakened prominently using 100 °C as the digestion temperature, and tourmaline powders can be observed even after 72 h of continuous heating with B contents within 1.09–1.23% (n = 5). To assess the accuracy of this developed method, the boron recovery of anhydrous lithium tetraborate was studied. It was found that the boron recoveries were within 96.59–102.12% (RSD < 1%, n = 5), demonstrating the accuracy and reliability of this proposed method, which exhibits advantages of high B preserving efficiency, and giving concentration information of both B and trace elements simultaneously. By applying such a boron–mannitol complex-based wet acid digestion method, the chemical composition of boron and trace elements in three tourmaline samples from different pegmatites were quantified, which provided valuable information to distinguish regional deposits and the associated evolution stages. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
39. Properties of Ni-B/B Composite Coatings Produced by the Electroless Method under Semi-Technical Line Conditions.
- Author
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Cieślak, Grzegorz, Gostomska, Marta, Dąbrowski, Adrian, Ciciszwili-Wyspiańska, Tinatin, Skroban, Katarzyna, Mazurek, Anna, Wojda, Edyta, Głowacki, Michał, Rygier, Tomasz, and Gajewska-Midziałek, Anna
- Subjects
COMPOSITE coating ,CHEMICAL reduction ,HEAT treatment ,SURFACE coatings ,ELECTROPLATING ,DISPERSION (Chemistry) - Abstract
Composite coatings have been successfully fabricated at the laboratory scale in many research centers around the world; however, it is still a major challenge to transfer the positive results of the work to the industrial scale. This paper presents the technology for the production of Ni-B and Ni-B/B composite coatings on a pilot experimental semi-technical line by chemical reduction. A process scheme for the fabrication of Ni-B layers and composite coatings with a nickel–boron matrix and a dispersive phase in the form of boron nanoparticles was developed. All stages of the fabrication process were described in detail. The dispersion phase of the boron particles was characterized, and the performance properties of the Ni-B and Ni-B/B composite coatings produced on a pilot electroplating line were studied. The structure and morphology of the Ni-B/B composite coatings were characterized for comparison with nickel–boron coatings. Their mechanical and tribological properties and adhesion to the substrate were studied. The influence of the dispersion phase of boron particles on the structure and functional properties of the composite coatings was evaluated. In order to improve the performance of the fabricated coatings, a heating process at 400 °C was carried out, and the performance of Ni-B and composite Ni-B/B coatings was studied after the heat treatment operation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. 1,3‐Bis(tricyanoborane)imidazoline‐2‐ylidenate Anion—A Ditopic Dianionic N‐Heterocyclic Carbene Ligand
- Author
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Maik Finze, Udo Radius, and Ludwig Zapf
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Steric effects ,Carbenes | Hot Paper ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,Medicinal chemistry ,Catalysis ,Adduct ,chemistry.chemical_compound ,Imidazolate ,Pyridine ,cyanoborate ,Research Articles ,010405 organic chemistry ,Ligand ,General Chemistry ,0104 chemical sciences ,Nickel ,anionic carbene ,chemistry ,boron ,ddc:546 ,N-heterocyclic carbene ,Carbene ,imidazolate ,Research Article ,Methyl iodide - Abstract
The 1,3‐bis(tricyanoborane)imidazolate anion 1 was obtained in high yield from lithium imidazolate and B(CN)3−pyridine adduct. Anion 1 is chemically very robust and thus allowed the isolation of the corresponding H5O2 + salt. Furthermore, monoanion 1 served as starting species for the novel dianionic N‐heterocyclic carbene (NHC), 1,3‐bis(tricyanoborane)imidazoline‐2‐ylidenate anion 3 that acts as ditopic ligand via the carbene center and the cyano groups at boron. First reactions of this new NHC 3 with methyl iodide, elemental selenium, and [Ni(CO)4] led to the methylated imidazolate ion 4, the dianionic selenium adduct 5, and the dianionic nickel tricarbonyl complex 6. These NHC derivatives provide a first insight into the electronic and steric properties of the dianionic NHC 3. Especially the combination of properties, such as double negative charge, different coordination sites, large buried volume and good σ‐donor and π‐acceptor ability, make NHC 3 a unique and promising ligand and building block., Unprecedentedly stable salts of the 1,3‐bis(tricyanoborane)imidazolate ion with different types of counterions were obtained on large scale. Deprotonation of the imidazolate ion provided access to the corresponding dianionic NHC that acts as ditopic ligand.
- Published
- 2021
41. <Original Papers>Removal of Cesium and Strontium from High-Activity-Level Water by Zeolites
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mixed zeolite ,high-activity-level water ,cesium ,adsorption rate ,strontium ,distribution coefficient ,boron ,mixing ratio - Abstract
The selective removal of Cs and Sr from high-activity-level water (HALW) has been studied by the use of various zeolites. The rate of adsorption of Cs and Sr increased with a decrease in size of zeolite particles, and the adsorption reached almost 100% after 5 h and 10 h of shaking for Cs and Sr, respectively. High distribution coefficients of Cs (K_=10^4~10^5) were obtained in the solution/zeolite ratio (V/m) region of about 300 to 1000. The presence of sodium ion fairly affected the distribution of Cs^+ and Sr^, and K_d values decreased with increasing concentration of Na^+. While the presence of boron almost had no effect on the distribution of Cs ; high K_ values (K_≧10^5) were obtained below 5000 ppm of boron. Distribution coefficients of Cs and Sr were also independent of the equilibrium pH in neutral and alkaline regions at the ionic strength of 0.1. The removal of Cs and Sr from simulated HALW was effectively achieved by the use of mixed zeolites, and the K_d value was 7.0×10^3ml/g at the mixing ratio of 48/52 of X/chabazite.
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- 1988
42. Comparative Ameliorative Efficacy of Tamarind Pulp against Boron on Fluorotic Calves Reared in Periphery Villages of Aluminium Smelter Plant
- Author
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M. Pati, Ghana Syam Parida, Ramesh Chandra Patra, Amit Raj Gupta, and Kruti Debnath Mandal
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chemistry ,Aluminium ,Pulp (paper) ,Smelting ,engineering ,chemistry.chemical_element ,engineering.material ,Boron ,Pulp and paper industry - Published
- 2020
43. Group 13 Element Trihalide Complexes of Anionic N‐Heterocyclic Carbenes
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Luong Phong Ho, Matthias Tamm, and Lisa Anders
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chemistry.chemical_element ,indium ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Medicinal chemistry ,Adduct ,chemistry.chemical_compound ,Moiety ,N-heterocyclic carbenes ,gallium ,Full Paper ,010405 organic chemistry ,Ligand ,aluminium ,Organic Chemistry ,Trihalide ,General Chemistry ,Full Papers ,Toluene ,0104 chemical sciences ,chemistry ,Lithium ,boron ,Carbene ,Derivative (chemistry) - Abstract
A series of group 13 complexes of the general type [{(WCA‐IDipp)EX3}Li(solv)] (E=B, Al, Ga, In; X=Cl, Br) that bear an anionic N‐heterocyclic carbene ligand with a weakly coordinating borate moiety (WCA‐IDipp, WCA=B(C6F5)3 and IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene) were prepared by the reaction of the respective group 13 trihalides (EX3) with the lithium salt [(WCA‐IDipp)Li ⋅ toluene]. The molecular structures of the BBr3, AlCl3, AlBr3, GaCl3 and InCl3 adducts were established by X‐ray diffraction analyses, revealing the formation of coordination polymers linked by halide‐lithium interactions, except for the indium derivative, which consists of isolated [Li(THF)4]+ and [(WCA‐IDipp)InCl3]− ions in the solid state., Expanding the library: Several group 13 complexes of the type [((WCA‐IDipp)EX3)Li] (E=B, Al, Ga and In; X=Cl, Br) that bear anionic N‐heterocyclic carbene ligands with a weakly coordinating borate moiety were prepared.
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- 2020
44. Electron‐Rich, Lewis Acidic Diborane Meets N‐Heterocyclic Aromatics: Formation and Electron Transfer in Cyclophane Boranes
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Erik Filbeck, Elisabeth Kaifer, Anna Widera, Hubert Wadepohl, and Hans-Jörg Himmel
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diborane ,Pyrazine ,Full Paper ,010405 organic chemistry ,Organic Chemistry ,Cationic polymerization ,Supramolecular chemistry ,Boranes ,General Chemistry ,Full Papers ,010402 general chemistry ,01 natural sciences ,Cyclophanes ,Catalysis ,0104 chemical sciences ,Bipyridine ,chemistry.chemical_compound ,Electron transfer ,chemistry ,redox ,Polymer chemistry ,boron ,viologens ,Cyclophane ,Diborane - Abstract
Herein reported are the reactions of an electron‐rich, Lewis acidic diborane with N‐heterocyclic aromatics to give first members of an unprecedented family of highly charged cationic cyclophanes with diboranyl units. Tetracationic cyclophanes with 4,4‘‐bipyridine/ 1,2‐bis(4‐pyridyl)ethylene and diboranyl units were synthesized and their redox chemistry was studied. Cyclisation of two diboranyl and two pyrazine units is accompanied by electron transfer from the diboranyl unit to the pyrazine. Our results pave the way for the integration of redox‐active diboranyl units into cyclophanes and supramolecular structures., Electron‐Rich cyclophanes: Unprecedented, highly charged cyclophanes with diboranyl units are synthesized and their redox and optical properties studied.
- Published
- 2020
45. Strong Lewis and Brønsted Acidic Sites in the Borosulfate Mg 3 [H 2 O→B(SO 4 ) 3 ] 2
- Author
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Henning A. Höppe, Philip Netzsch, Florian Pielnhofer, Ingo Krossing, and Regina Stroh
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Thermogravimetric analysis ,borosulfates ,chemistry.chemical_element ,Infrared spectroscopy ,010402 general chemistry ,01 natural sciences ,Catalysis ,Adduct ,Borosulfates | Hot Paper ,Molecule ,ddc:530 ,Lewis acids and bases ,Boron ,Lewis acid base adduct ,Brønsted acid ,010405 organic chemistry ,Chemistry ,Communication ,General Chemistry ,Communications ,Lewis acid ,0104 chemical sciences ,Crystallography ,Density functional theory ,silicate analogue ,Brønsted–Lowry acid–base theory - Abstract
Borosulfates provide fascinating structures and properties that go beyond a pure analogy to silicates. Mg3[H2O→B(SO4)3]2 is the first borosulfate featuring a boron atom solely coordinated by three tetrahedra. Thus, the free Lewis acidic site forms a Lewis acid–base adduct with a water molecule. This is unprecedented for borosulfate chemistry and even for borates. Quantum chemical calculations on water exchange reactions with BF3 and B(C6F5)3 revealed a higher Lewis acidity for the borosulfate anion. Moreover, proton exchange reactions showed a higher Brønsted acidity than comparable silicates or phosphates. Additionally, Mg3[H2O→B(SO4)3]2 was characterised by X‐ray diffraction, infrared spectroscopy, thermogravimetric analysis, and density functional theory (DFT) calculations., The ever‐expanding chemistry of borosulfates is enriched by the novel borosulfate Mg3[H2O→B(SO4)3]2 featuring an unprecedented Lewis acid–base adduct of water to the anion [B(SO4)3]3−. Isodesmic exchange calculations revealed high Lewis and Brønsted acidity, opening new insights and perspectives for this fascinating silicate‐analogous material class.
- Published
- 2021
46. Dithiophene‐Fused Oxadiborepins and Azadiborepins: A New Class of Highly Fluorescent Heteroaromatics
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Andreas Helbig, Holger Helten, Jonas Bachmann, Ivo Krummenacher, Merian Crumbach, Holger Braunschweig, and Lars Fritze
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Materials science ,polycycles ,chemistry.chemical_element ,isoelectronic analogues ,010402 general chemistry ,Ring (chemistry) ,Photochemistry ,01 natural sciences ,Catalysis ,BN compounds ,Anisotropy ,Boron ,Quantum ,010405 organic chemistry ,Communication ,π‐Conjugated Molecules | Hot Paper ,Aromaticity ,General Medicine ,aromaticity ,General Chemistry ,Fluorescence ,Communications ,0104 chemical sciences ,chemistry ,ddc:540 ,Cyclic voltammetry ,boron ,Current density - Abstract
Access to dithiophene‐fused oxadiborepins and the first azadiborepins attained via a modular synthesis route are presented. The new compounds emit intense blue light, some of which demonstrate fluorescence quantum yields close to unity. Cyclic voltammetry (CV) revealed electrochemically reversible one‐electron reduction processes. The weak aromatic character of the novel 1,2,7‐azadiborepin ring is demonstrated with in‐depth theoretical investigations using nucleus‐independent chemical shift (NICS) scans and anisotropy of the induced current density (ACID) calculations., Dithienooxa‐ and ‐azadiborepins are accessible in a modular way from a common precursor. These BNB‐doped polycyclic aromatic hydrocarbons (PAHs) are highly efficient blue‐light emitters with quantum yields up to 96 %. In‐depth theoretical studies reveal that the previously unknown azadiborepin ring system is weakly aromatic.
- Published
- 2021
47. Reactions of B2(o‐tolyl)4 with Boranes: Assembly of the Pentaborane(9), HB[B(o‐tolyl)(μ‐H)]4
- Author
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Karlee L. Bamford, Douglas W. Stephan, and Zheng-Wang Qu
- Subjects
Boron Chemistry | Hot Paper ,010405 organic chemistry ,Hydride ,Aryl ,Communication ,Boranes ,General Chemistry ,Borane ,010402 general chemistry ,Metathesis ,01 natural sciences ,Medicinal chemistry ,Catalysis ,Diborane(4) ,Communications ,0104 chemical sciences ,Pentaborane ,chemistry.chemical_compound ,chemistry ,diborane(4) ,metathesis ,pentaborane(9) ,boron ,cluster ,Diborane - Abstract
Reactions of the diborane(4) B2(o‐tolyl)4 and monohydridoboranes are shown to give B(o‐tolyl)3 and (o‐tolyl)BR2 (R2=(C8H14) 3, cat 4, pin 5, (C6F5)2 6) as the major products. The corresponding reaction with BH3‐sources gives complex mixtures, resulting from hydride/aryl exchange, dimerization and borane elimination. This led to the isolation of the first tetra‐substituted pentaborane(9) HB[B(o‐tolyl)(μ‐H)]4 8. The reaction pathways are probed experimentally and by computations., The diborane(4) B2(o‐tolyl)4 reacts with species with B−H bonds giving a complex mixture arising from hydride/aryl exchange, dimerization and borane elimination. Use of BH3 sources led to the isolation of the first tetra‐substituted pentaborane(9) HB[B(o‐tolyl)(μ‐H)]4.
- Published
- 2021
48. Superseding β‐Diketiminato Ligands: An Amido Imidazoline‐2‐Imine Ligand Stabilizes the Exhaustive Series of B=X Boranes (X=O, S, Se, Te)
- Author
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Hadi Dolati, Bartosz Trzaskowski, René Frank, and Lars Denker
- Subjects
ligand design ,Imine ,NacNac ,Boranes ,010402 general chemistry ,01 natural sciences ,Medicinal chemistry ,Catalysis ,chemistry.chemical_compound ,Moiety ,Reactivity (chemistry) ,Structure Elucidation | Hot Paper ,Lewis acids and bases ,Research Articles ,010405 organic chemistry ,Ligand ,structure elucidation ,Isolobal principle ,General Medicine ,General Chemistry ,0104 chemical sciences ,chemistry ,chalcogens ,Lewis acids ,boron ,Research Article - Abstract
Boron reluctantly forms B=X (X=O, S, Se, Te) moieties, which has stimulated the quest for such species in the past few years. Based on the N,N′‐chelating β‐diketiminato ligand (HNacNac), a new amido imidazoline‐2‐imine ligand system (HAmIm) is presented, giving rise to the isolation of an exhaustive series of Lewis acid free, monomeric chalcogen B=X boranes with documented π‐bond character between boron and the chalcogen. The chalcogenoboranes are isoelectronic and isolobal to the respective ketones. The chemical behavior of the oxoborane (B=O) strongly resembles the classical carbonyl reactivity in C=O bonds. The improved stability provided by HAmIm arises from the formation of more‐stable five‐membered boron chelates versus the six‐membered NacNac analogues and from the imidazoline‐2‐imine moiety providing enhanced σ‐ and π‐donation. The HAmIm ligand class may supersede the widely employed NacNac system in certain applications., The new N,N′‐chelating amido imidazoline‐2‐imine ligand (HAmIm) was designed to supersede the widely employed β‐diketiminato ligand (HNacNac). The superior stability of the HAmIm system is exemplified for a series of chalcogenoboranes with confirmed B=X double bonds (X=O, S, Se, Te), which are isoelectronic and isolobal to ketones, including their heavier analogues.
- Published
- 2021
49. Investigating the Effect of Coagulation and Flocculation - Adsorption Process on Boron Removal from Industrial Wastewater (Case Study: Ceramic Tile Industry)
- Author
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Mohammad Hassan Ehrampoush, Hadi Eslami, T. Zarei Mahmudabadi, and Ali Ebrahimi
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Flocculation ,business.industry ,chemistry.chemical_element ,Pulp and paper industry ,Industrial wastewater treatment ,Adsorption ,chemistry ,visual_art ,Scientific method ,visual_art.visual_art_medium ,Coagulation (water treatment) ,Medicine ,Ceramic ,Tile ,Boron ,business - Published
- 2021
50. Bithiophene-Cored, mono-, bis-, and tris-(Trimethylammonium)-Substituted, bis-Triarylborane Chromophores: Effect of the Number and Position of Charges on Cell Imaging and DNA/RNA Sensing
- Author
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Sarina M, Berger, Jessica, Rühe, Johannes, Schwarzmann, Alexandra, Phillipps, Ann-Katrin, Richard, Matthias, Ferger, Ivo, Krummenacher, Lidija-Marija, Tumir, Željka, Ban, Ivo, Crnolatac, Dragomira, Majhen, Ivan, Barišić, Ivo, Piantanida, Domenik, Schleier, Stefanie, Griesbeck, Alexandra, Friedrich, Holger, Braunschweig, and Todd B, Marder
- Subjects
Full Paper ,luminescence ,RNA ,DNA ,Full Papers ,bioimaging ,boron ,singlet oxygen ,nucleic acid - Abstract
The synthesis, photophysical, and electrochemical properties of selectively mono‐, bis‐ and tris‐dimethylamino‐ and trimethylammonium‐substituted bis‐triarylborane bithiophene chromophores are presented along with the water solubility and singlet oxygen sensitizing efficiency of the cationic compounds Cat1+ , Cat2+ , Cat(i)2+ , and Cat3+ . Comparison with the mono‐triarylboranes reveals the large influence of the bridging unit on the properties of the bis‐triarylboranes, especially those of the cationic compounds. Based on these preliminary investigations, the interactions of Cat1+ , Cat2+ , Cat(i)2+ , and Cat3+ with DNA, RNA, and DNApore were investigated in buffered solutions. The same compounds were investigated for their ability to enter and localize within organelles of human lung carcinoma (A549) and normal lung (WI38) cells showing that not only the number of charges but also their distribution over the chromophore influences interactions and staining properties., Four selectively mono ‐, bis ‐ and tris ‐trimethylammonium‐substituted, bithiophene‐bridged bis‐triarylboranes were synthesized and their potential biological applications were investigated including live cell imaging and photo‐induced cell death. It is demonstrated that their photophysical and electrochemical properties and their interactions with DNAs, RNA and cells, are strongly influenced by the number and distribution of charges within the compounds.
- Published
- 2021
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