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1.
Food Chem ; 393: 133278, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-35653986

RESUMO

Determination of cholesterol in food matrices is essential for quality control concerning the health of consumers. Herein, a simple electrochemical approach for cholesterol quantitation in dairy products is evaluated. The newly developed differential pulse voltammetric method using acetonitrile-perchloric acid mixture as a supporting electrolyte is statistically compared to GC-MS and HPLC-UV. Oxidation signals of cholesterol at +1.5 V and +1.4 V (vs. Ag/AgNO3 in acetonitrile) provide detection limits of 4.9 µM and 6.1 µM on boron-doped diamond and glassy carbon electrodes, respectively. A simple liquid-liquid extraction procedure from dairy products into hexane resulted in a recovery rate of (74.8 ± 3.8)%. The method provides results in close agreement (at a 95% confidence level) with GC-MS, while HPLC-UV resulted in a significant difference in estimated cholesterol concentrations for all samples. This newly developed method is a simpler, faster and cheaper alternative to instrumentally demanding MS-based methods and clearly outperforms HPLC-UV.


Assuntos
Boro , Laticínios , Acetonitrilas , Colesterol , Eletrodos
2.
Chem Commun (Camb) ; 58(51): 7188-7191, 2022 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-35670546

RESUMO

We report a boron dipyrromethene that is chiral at boron and carbon (B*C*-BODIPY) and accessible through a two-pot, one-step synthesis-an interrupted Knoevenagel condensation. The electronic circular dichroism spectra of chiral high performance liquid chromatography-resolved enantiomers show clear Cotton effects (∣gabs∣ ∼ 2.0 × 10-4) in the visible region, suggesting efficient chirality induction to the otherwise achiral BODIPY. The dye's unusually weak fluorescence (Φfl < 0.01) is attributed partly to vibrational relaxations, as revealed by viscosity experiments, and partly to probable intersystem crossing that may be facilitated by the reduced symmetry of the bent-shaped molecular geometry.


Assuntos
Boro , Carbono , Dicroísmo Circular , Porfobilinogênio/análogos & derivados
3.
Chem Commun (Camb) ; 58(50): 7034-7037, 2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35647670

RESUMO

The origins of the reactivity of strain-increase allylborations were computationally investigated. The low reactivity of vinylcyclopropyl boronates is due to weak electronic interactions between benzaldehyde and allylboronates. By increasing the acidity of the boron center, the reactivity is significantly improved because the stronger stabilizing O→B interaction effectively compensates for destabilizing steric effects.


Assuntos
Boro
4.
ACS Appl Bio Mater ; 5(6): 3049-3056, 2022 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-35671477

RESUMO

Alzheimer's disease (AD), known as a common incurable and elderly neurodegenerative disease, has been widely explored for accurate detection of its biomarker (Aß oligomers) for early diagnosis. Although great efforts have been made, it is still of great importance to develop fluorescence probes for Aß oligomers with good selectivity and low background. Herein, starting from BODIPY493/503 (a commercial dye for neutral lipid droplets), which exhibited a small Stokes shift and no response toward Aß peptides, two fluorescence probes 5MB-SZ and B-SZ with a benzothiazole rotor at the 2-position of the BODIPY core and a methyl or benzyl group at the meso position have been designed and synthesized, which exhibited excellent optical properties/stability and could successfully image ß-amyloid fibrils and viscosity. Upon exposure to Aß oligomers, the fluorescence intensity of 5MB-SZ was enhanced by 43.64-fold with the corresponding fluorescence quantum yields changing from 0.85% to 27.43%. Meanwhile, probe 5MB-SZ showed a highly sensitive viscosity response in both solutions and living cells. In vitro and in vivo experiments confirmed that probe 5MB-SZ exhibited an excellent capacity for imaging ß-amyloid fibrils. Therefore, 5MB-SZ, as a rotor-tuning BODIPY analogue, could possibly serve as a highly potential and powerful fluorescence probe for early diagnosis of AD.


Assuntos
Doença de Alzheimer , Doenças Neurodegenerativas , Idoso , Doença de Alzheimer/diagnóstico , Amiloide , Peptídeos beta-Amiloides , Boro , Humanos , Porfobilinogênio/análogos & derivados , Viscosidade
5.
Molecules ; 27(11)2022 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-35684340

RESUMO

Hundreds of billions of commensal microorganisms live in and on our bodies, most of which colonize the gut shortly after birth and stay there for the rest of our lives. In animal models, bidirectional communications between the central nervous system and gut microbiota (Gut-Brain Axis) have been extensively studied, and it is clear that changes in microbiota composition play a vital role in the pathogenesis of various neurodevelopmental and neurodegenerative disorders, such as Autism Spectrum Disorder, Alzheimer's disease, Parkinson's disease, Multiple Sclerosis, Amyotrophic Lateral Sclerosis, anxiety, stress, and so on. The makeup of the microbiome is impacted by a variety of factors, such as genetics, health status, method of delivery, environment, nutrition, and exercise, and the present understanding of the role of gut microbiota and its metabolites in the preservation of brain functioning and the development of the aforementioned neurological illnesses is summarized in this review article. Furthermore, we discuss current breakthroughs in the use of probiotics, prebiotics, and synbiotics to address neurological illnesses. Moreover, we also discussed the role of boron-based diet in memory, boron and microbiome relation, boron as anti-inflammatory agents, and boron in neurodegenerative diseases. In addition, in the coming years, boron reagents will play a significant role to improve dysbiosis and will open new areas for researchers.


Assuntos
Transtorno do Espectro Autista , Microbiota , Doenças Neurodegenerativas , Probióticos , Animais , Transtorno do Espectro Autista/patologia , Boro , Encéfalo/patologia , Doenças Neurodegenerativas/patologia , Probióticos/uso terapêutico
6.
Molecules ; 27(11)2022 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-35684365

RESUMO

Fluorinated boron species are a very important group of organoboron compounds used first of all as receptors of important bioanalytes, as well as biologically active substances, including Tavaborole as an antifungal drug. The presence of substituents containing fluorine atoms increases the acidity of boronic compounds, which is crucial from the point of view of their interactions with analytes or certain pathogen's enzymes. The review discusses the electron acceptor properties of fluorinated boronic species using both the acidity constant (pKa) and acceptor number (AN) in connection with their structural parameters. The NMR spectroscopic data are also presented, with particular emphasis on 19F resonance due to the wide range of information that can be obtained from this technique. Equilibria in solutions, such as the dehydration of boronic acid to form boroxines and their esterification or cyclization with the formation of 3-hydroxyl benzoxaboroles, are discussed. The results of the latest research on the biological activity of boronic compounds by experimental in vitro methods and theoretical calculations using docking studies are also discussed.


Assuntos
Boro , Flúor , Antifúngicos/química , Ácidos Borônicos/química , Elétrons , Flúor/química
7.
Molecules ; 27(11)2022 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-35684388

RESUMO

Tetrachlorinated phthalimide analogues bearing a boron-pinacolate ester group were synthesised via two synthetic routes and evaluated in their glycosidase modulating and anticancer properties, with a view to use them in boron neutron capture therapy (BNCT), a promising radiation type for cancer, as this therapy does little damage to biological tissue. An unexpected decarbonylation/decarboxylation to five 2,3,4,5-tetrachlorobenzamides was observed and confirmed by X-ray crystallography studies, thus, giving access to a family of borylated 2,3,4,5-tetrachlorobenzamides. Biological evaluation showed the benzamide drugs to possess good to weak potencies (74.7-870 µM) in the inhibition of glycosidases, and to have good to moderate selectivity in the inhibition of a panel of 18 glycosidases. Furthermore, in the inhibition of selected glycosidases, there is a core subset of three animal glycosidases, which is always inhibited (rat intestinal maltase α-glucosidase, bovine liver ß-glucosidase and ß-galactosidase). This could indicate the involvement of the boron atom in the binding. These glycosidases are targeted for the management of diabetes, viral infections (via a broad-spectrum approach) and lysosomal storage disorders. Assays against cancer cell lines revealed potency in growth inhibition for three molecules, and selectivity for one of these molecules, with the growth of the normal cell line MCF10A not being affected by this compound. One of these molecules showed both potency and selectivity; thus, it is a candidate for further study in this area. This paper provides numerous novel aspects, including expedited access to borylated 2,3,4,5-tetrachlorophthalimides and to 2,3,4,5-tetrachlorobenzamides. The latter constitutes a novel family of glycosidase modulating drugs. Furthermore, a greener synthetic access to such structures is described.


Assuntos
Terapia por Captura de Nêutron de Boro , Neoplasias , Animais , Boro/química , Boro/farmacologia , Compostos de Boro/farmacologia , Bovinos , Glicosídeo Hidrolases , Ratos
8.
Carbohydr Polym ; 291: 119588, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35698343

RESUMO

Chronic wounds resulting from bacterial infection are a global healthcare challenge as they usually impair the healing process and induce various complications. In this work, a chitosan (CS) membrane loaded with copper boron-imidazolate framework (Cu-BIF) was successfully prepared by self-assembly method for bacterial-infected wound-healing dressing. The as-prepared Cu-BIF/CS membrane possessed desirable biocompatibility. The antibacterial activity of Cu-BIF/CS membrane was evaluated by the spread plate and disc diffusion method, which was also verified by the fluorescence-based viability and morphological changes of bacteria. Moreover, Cu-BIF/CS membrane could increase wound closure rate and accelerate skin regeneration via combination therapy with chitosan, Cu2+ and hydroxyl radicals during infected wound healing process. These results exhibit that Cu-BIF/CS membrane has great potential as wound dressings in the field of clinical treatment of bacterial-infected wounds.


Assuntos
Quitosana , Infecção dos Ferimentos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bactérias , Bandagens/microbiologia , Boro , Quitosana/farmacologia , Cobre/farmacologia , Humanos , Cicatrização , Infecção dos Ferimentos/tratamento farmacológico
9.
Sci Rep ; 12(1): 9129, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35650237

RESUMO

Boron-based nano-formulations look very promising for biomedical applications, including photo- and boron neutron capture therapies, but the fabrication of non-toxic water-dispersible boron nanoparticles (NPs), which contain the highest boron atom concentration, is difficult using currently available chemical and plasma synthesis methods. Here, we demonstrate purely aqueous synthesis of clean boron NPs by methods of femtosecond laser ablation from a solid boron target in water, thus free of any toxic organic solvents, and characterize their properties. We show that despite highly oxidizing water ambience, the laser-ablative synthesis process follows an unusual scenario leading to the formation of boron NPs together with boric acid (H3BO3) as an oxidation by-product coating the nanoparticles, which acts to stabilize the elemental boron NPs dispersion. We then demonstrate the purification of boron NPs from residual boric acid in deionized water, followed by their coating with polyethylene glycol to improve colloidal stability and biocompatibility. It was found that the formed NPs have a spherical shape with averaged size of about 37 nm, and are composed of elemental boron in mostly amorphous phase with the presence of certain crystalline fraction. The synthesized NPs demonstrate low toxicity and exhibit strong absorption in the NIR window of relative tissue transparency, promising their use in photoacoustic imaging and phototherapy, in addition to their promise for neutron capture therapy. This combined potential ability of generating imaging and therapy functionalities makes laser-synthesized B NPs a very promising multifunctional agent for biomedical applications.


Assuntos
Boro , Nanopartículas , Linhagem Celular Tumoral , Lasers , Nanopartículas/química , Água/química
10.
J Mol Model ; 28(7): 181, 2022 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-35668144

RESUMO

The performance of nanotubes (NT) of carbon (CC), aluminium-nitrogen (AlN), and boron-nitrogen (BN) as a sensor and nanocarrier for mercaptopurine (MCP) was investigated by means of a theoretical approach. The calculated negative values of adsorption energy showed the interaction and adsorption of MCP. Highest-occupied molecular orbital (HOMO) and lowest-unoccupied molecular orbital (LUMO) distributions were only found on the NT counter portion of the drug-nanotube not on MCP for AlN-NT and BN-NT while HOMO is over MCP and LUMO is over NT for CC-NT. The polarizability of MCP-NTs is greater than that of MCP. Raman wavenumbers of MCP are enhanced in NTs, and hence, NTs can act as a sensor for the detection of MCP. Solvent dependency on adsorption behaviour is also presented in the manuscript, where we found that the AlN nanotube showed exceptionally high free energy of adsorption over other nanotubes in all solvent mediums. Solvation-free energies were also reported. Noncovalent interaction scattered plot also showed significant intermolecular interaction between AlN nanotubes and the mercaptopurine when compared to other nanotubes under study. To find the antiviral activity of MCP and MCP-NTs against antiviral activities, docking and molecular dynamics simulations were performed with 1HMP PDB. Recovery times show that MCP desorption occurs quickly. The MD simulations and docking results show that BN and CC-NTs with MCP show good activity as drug carriers.


Assuntos
Boro , Nanotubos , Adsorção , Alumínio , Antivirais , Carbono , Mercaptopurina , Nitrogênio , Solventes , Tionas
11.
J Org Chem ; 87(12): 7712-7719, 2022 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-35675709

RESUMO

Organoboron complexes have gained considerable attention owing to their versatile chemical structures and excellent optical properties. Nevertheless, stable seven-membered organoboron complexes have rarely been reported because of their challenging synthesis. Herein, seven-membered N,O-boron-chelated dyes, whose photophysical properties have been thoroughly studied via spectroscopic tests and theoretical calculations, were synthesized from commercially available materials via a facile method. Single-crystal X-ray diffraction studies provided evidence of their seven-membered ring N,O-boron-chelated skeleton. These complexes produced singlet oxygen species under laser irradiation, endowing them with potential application as a photosensitizer to treat superficial tumors (B16 cells). Our study provided a new skeleton to construct versatile organoboron compounds and offered a strategy to design heavy-atom-free photosensitizers.


Assuntos
Compostos de Boro , Boro , Compostos de Boro/química , Cristalografia por Raios X , Fármacos Fotossensibilizantes , Oxigênio Singlete
12.
Anal Chim Acta ; 1219: 340033, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35715133

RESUMO

Poisonous mushroom may cause fatal harm to human and animal, but its rapid detection still faces a great challenge. The paper reports synthesis of gold-aspartic acid, glycine acid-functionalized and boron-doped graphene quantum dot nanohybrid (AGB-GQD@Au) for the electrochemical detection of α-amanitin. AGB-GQD was prepared by pyrolysis and then reacted with chloroauric acid to produce gold nanoparticles. AGB-GQD@Au offers 12.5 nm-sized particles and Schottky heterojunction, improving the catalytic activity. AGB-GQD@Au connected with hairpin DNA and thionine by Au-S bonds was used as redox probe for electrochemical detection of α-amanitin coupled with one target-induced DNA cycle amplification strategy. α-Amanitin specifically hybridizes with aptamer in duplex DNA to release auxiliary strand DNA. The released DNA triggers one DNA cycle process and brings one redox probe to the electrode surface. By the DNA cycle, one target brings many redox probes to the electrode surface, producing a significant signal amplification. The detection signal was further enhanced by the catalysis of AGB-GQD@Au towards redox of thionine. Differential pulse voltammetric current increases linearly with the increasing α-amanitin in the range from 4 to 4 × 105 fM with the detection limit of 1.2 fΜ (S/N = 3). The analytical method provides advantages of sensitivity, selectivity and repeatability. It has been successfully applied in electrochemical detection of α-amanitin in blood.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Grafite , Nanopartículas Metálicas , Pontos Quânticos , Alfa-Amanitina , Animais , Aptâmeros de Nucleotídeos/química , Ácido Aspártico , Técnicas Biossensoriais/métodos , Boro , DNA , Técnicas Eletroquímicas/métodos , Glicina , Ouro/química , Grafite/química , Limite de Detecção , Nanopartículas Metálicas/química , Pontos Quânticos/química
13.
J Colloid Interface Sci ; 624: 1-13, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-35660878

RESUMO

Cellulose acetate membrane (CAM) has become one of the most widely used membrane materials by virtue of stability and hydrophilicity. In this work, to achieve the aim of selective recognition and separation of drug molecule shikimic acid (SA), an effective recognition tactics was proposed by combining boron affinity technology with surface imprinting strategy based on cellulose acetate membrane with low price and biocompatibility. The supporting CAM material was prepared through the phase inversion technique by continuous adjustment of different factors including solvent type and kinds of pore-forming agents, and the optimal CAM with multistage structure and highly porosity was applied for the imprinting of SA. Then the imprinted polymer membrane (MIPs-CAM) was developed via boron affinity surface imprinting polymerization. Various methods (FT-IR, UV-vis, SEM, XPS, AFM and TGA) were used to characterize the structure, morphology, elemental composition, surface roughness and thermal property of the obtained membrane. The as-prepared MIPs-CAM showed homogeneous and abundant imprinted layer, good thermal stability. The batch adsorption results showed that the MIPs-CAM had fast adsorption kinetics, specific recognition ability, and the adsorption capacity could obtain 63.598 mg g-1, which was two times higher than that of non-imprinted membrane (NIPs-CAM). The adsorption isotherms conformed to the Langmuir isotherm and the adsorption processes were spontaneous and endothermic. Additionally, the adsorption capacity of MIPs-CAM still reached 85% of the initial result after five cycles. The experimental results revealed that the molecularly imprinted membrane possessed the advantages of high selectivity and easy recovery compared with the traditional molecular imprinted polymers for SA separation. These results indicate that boron affinity MIPs-CAM with high performance will provide a promising platform for the separation and purification of other cis-diol drug molecules from environmental resources.


Assuntos
Impressão Molecular , Polímeros , Adsorção , Boro , Impressão Molecular/métodos , Polimerização , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Clin Exp Dent Res ; 8(3): 757-762, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35543493

RESUMO

OBJECTIVES: While various approaches are available for tooth whitening, the basic concept employs the use of peroxides in the form of gels, which are applied to tooth surfaces. Previous studies have shown that reactive oxygen species acting as potent disinfectants can be produced using boron-doped diamond (BDD) electrodes for the electrolysis of water. With these electrodes being applicable, for example, for endodontic treatment, it was the goal of this pilot study to use such electrodes for tooth whitening. MATERIAL AND METHODS: Two groups (n = 10) of intact clinical crowns were obtained by horizontally cutting off roots of extracted human teeth. The crowns were either bleached by applying a commercially available agent based on 40% hydrogen peroxide or were immersed in saline undergoing electrolysis with BDD electrodes. Whitening of specimens was judged on standardized photographs by examiners with three different levels of experience. Statistical analysis was based on Gwet's AC2 coefficient with quadratic weights, Shapiro-Wilk tests, and two-way analysis of variance of aligned rank transformed data (level of significance set at α = .05). RESULTS: Levels of reliability ranging from fair to substantial were recorded for single persons while the level of reliability ranged between fair and moderate for groups of raters. The level of experience had no significant effect on the ratings (p = .2500). The bleaching method had a significant effect on ratings (p = .0005) with BDD electrodes showing less effect. CONCLUSIONS: Bleaching by applying BDD electrodes was possible, but was not as effective as the use of commercially available in-office whitening gel. A potential explanation may be seen in different concentrations of reactive oxygen species.


Assuntos
Clareamento Dental , Boro , Eletrodos , Géis , Humanos , Projetos Piloto , Espécies Reativas de Oxigênio , Reprodutibilidade dos Testes , Clareamento Dental/métodos
15.
Biomed Res Int ; 2022: 1027288, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35505877

RESUMO

Combined stress has been seen as a major threat to world agriculture production. Maize is one of the leading cereal crops of the world due to its wide spectrum of growth conditions and is moderately sensitive to salt stress. A saline soil environment is a major factor that hinders its growth and overall yield and causes an increase in the concentration of micronutrients like boron, leading to excess over the requirement of the plant. Boron toxicity combined with salinity has been reported to be a serious threat to the yield and quality of maize. The response signatures of the maize plants to the combined effect of salinity and boron stress have not been studied well. We carried out an integrative systems-level analysis of the publicly available transcriptomic data generated on tolerant maize (Lluteño maize from the Atacama Desert, Chile) landrace under combined salt and boron stress. We identified significant biological processes that are differentially regulated in combined salt and boron stress in the leaves and roots of maize, respectively. Protein-protein interaction network analysis identified important roles of aldehyde dehydrogenase (ALDH), galactinol synthase 2 (GOLS2) proteins of leaf and proteolipid membrane potential regulator (pmpm4), metallothionein lea protein group 3 (mlg3), and cold regulated 410 (COR410) proteins of root in salt tolerance and regulating boron toxicity in maize. Identification of transcription factors coupled with regulatory network analysis using machine learning approach identified a few heat shock factors (HSFs) and NAC (NAM (no apical meristem, Petunia), ATAF1-2 (Arabidopsis thaliana activating factor), and CUC2 (cup-shaped cotyledon, Arabidopsis)) family transcription factors (TFs) to play crucial roles in salt tolerance, maintaining reactive oxygen species (ROS) levels and minimizing oxidative damage to the cells. These findings will provide new ways to design targeted functional validation experiments for developing multistress-resistant maize crops.


Assuntos
Arabidopsis , Boro , Boro/toxicidade , Produtos Agrícolas , Salinidade , Biologia de Sistemas , Fatores de Transcrição/genética , Zea mays/genética
16.
Sci Rep ; 12(1): 8510, 2022 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-35595847

RESUMO

Due to the pivotal role of angiogenesis in bone regeneration, the angiogenic properties of biomaterials are of high importance since they directly correlate with the biomaterials' osteogenic potential via 'angiogenic-osteogenic coupling' mechanisms. The impact of bioactive glasses (BGs) on vascularization can be tailored by incorporation of biologically active ions such as boron (B). Based on the ICIE16-BG composition (in mol%: 49.5 SiO2, 36.3 CaO, 6.6 Na2O, 1.1 P2O5, 6.6 K2O), three B-doped BGs have been developed (compositions in mol%: 46.5/45.5/41.5 SiO2, 36.3 CaO, 6.6 Na2O, 1.1 P2O5, 6.6 K2O, 3/4/8 B2O3). The influence of B-doping on the viability, cellular osteogenic differentiation and expression of osteogenic and angiogenic marker genes of bone marrow-derived mesenchymal stromal cells (BMSCs) was analyzed by cultivating BMSCs in presence of the BGs' ionic dissolution products (IDPs). Furthermore, the influence of the IDPs on angiogenesis was evaluated in ovo using a chorioallantoic membrane (CAM) assay. The influence of B-doped BGs on BMSC viability was dose-dependent, with higher B concentrations showing limited negative effects. B-doping led to a slight stimulation of osteogenesis and angiogenesis in vitro. In contrast to that, B-doping significantly enhanced vascularization in ovo, especially in higher concentrations. Differences between the results of the in vitro and in ovo part of this study might be explained via the different importance of vascularization in both settings. The implementation of new experimental models that cover the 'angiogenic-osteogenic coupling' mechanisms is highly relevant, for instance via extending the application of the CAM assay from solely angiogenic to angiogenic and osteogenic purposes.


Assuntos
Boro , Osteogênese , Materiais Biocompatíveis/farmacologia , Boro/farmacologia , Sobrevivência Celular , Vidro , Íons , Silicatos/farmacologia , Dióxido de Silício , Solubilidade
17.
Environ Res ; 212(Pt C): 113362, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35525294

RESUMO

The electrophoretic deposition of titanium dioxide (TiO2) nanoparticles (Degussa P25) onto a boron-doped diamond (BDD) substrate was carried out to produce a photoanode (TiO2/BDD) to apply in the degradation and mineralization of sodium diclofenac (DCF-Na) in an aqueous medium using photoelectrocatalysis (PEC). This study was divided into three stages: i) photoanode production through electrophoretic deposition using three suspensions (1.25%, 2.5%, 5.0% w/v) of TiO2 nanoparticles, applying 4.8 V for 15 and 20 s; ii) characterization of the TiO2/BDD photoanode using scanning electron microscopy and cyclic voltammetry response with the [Fe(CN)6]3-/4- redox system; iii) degradation of DCF-Na (25 mg L-1) through electrochemical oxidation (EO) on BDD and PEC on TiO2/BDD under dark and UVC-light conditions. The degradation of DCF-Na was evaluated using high-performance liquid chromatography and UV-Vis spectroscopy, and its mineralization measured using total organic carbon and chemical oxygen demand. The results showed that after 2 h, DCF-Na degradation and mineralization reached 98.5% and 80.1%, respectively, through PEC on the TiO2/BDD photoanode at 2.2 mA cm-2 under UVC illumination, while through EO on BDD applying 4.4 mA cm-2, degradation and mineralization reached 85.6% and 76.1%, respectively. This difference occurred because of the optimal electrophoretic formation of a TiO2 film with a 9.17 µm thickness on the BDD (2.5% w/v TiO2, time 15 s, 4.8 V), which improved the electrocatalysis and oxidative capacity of the TiO2/BDD photoanode. Additionally, PEC showed a lower specific energy consumption (1.55 kWh m-3). Thus, the use of nanostructured TiO2 films deposited on BDD is an innovative photoanode alternative for the photoelectrocatalytic degradation of DCF-Na, which substantially improves the degradation capacity of bare BDD.


Assuntos
Boro , Poluentes Químicos da Água , Diclofenaco , Eletrodos , Oxirredução , Titânio/química , Poluentes Químicos da Água/química
18.
Org Lett ; 24(19): 3570-3575, 2022 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-35512319

RESUMO

A novel route has been reported for C-H hydroxylation of benzyl compounds directed by a 3,4,5-tribromopyrazole auxiliary via boronation/oxidation using BBr3 and NaBO3·4H2O. The strategy exhibits outstanding site selectivity and affords the corresponding phenols in moderate to excellent yields under metal-free conditions. Besides, this protocol can be achieved in one pot, which is highly promising as a practical method for use in a multistep organic synthetic process.


Assuntos
Boro , Metais , Hidroxilação , Oxirredução , Fenóis
19.
Org Lett ; 24(19): 3455-3460, 2022 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-35544734

RESUMO

The cyclopropanation of alkenyl boronates and subsequent derivatization of the boronate handle are a convenient strategy to quickly build molecular complexity and access diverse compounds with a high sp3 fraction. Herein, we describe the asymmetric cyclopropanation of enantioenriched hydrobenzoin-derived alkenyl boronic esters toward the synthesis of tertiary and secondary cyclopropyl boronates.


Assuntos
Boro , Ésteres , Ácidos Borônicos , Estereoisomerismo
20.
Sci Rep ; 12(1): 9061, 2022 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-35641637

RESUMO

In this work, we report, the synthesis of Boron and Sulfur co-doped graphene quantum dots (BS-GQDs) and its applicability as a label-free fluorescence sensing probe for the highly sensitive and selective detection of dopamine (DA). Upon addition of DA, the fluorescence intensity of BS-GQDs were effectively quenched over a wide concentration range of DA (0-340 µM) with an ultra-low detection limit of 3.6 µM. The quenching mechanism involved photoinduced electron transfer process from BS-GQDs to dopamine-quinone, produced by the oxidization of DA under alkaline conditions. The proposed sensing mechanism was probed using a detailed study of UV-Vis absorbance, steady state and time resolved fluorescence spectroscopy. The high selectivity of the fluorescent sensor towards DA is established. Our study opens up the possibility of designing a low-cost biosensor which will be suitable for detecting DA in real samples.


Assuntos
Grafite , Pontos Quânticos , Boro , Dopamina/química , Corantes Fluorescentes/química , Grafite/química , Pontos Quânticos/química , Enxofre
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