High‐grade periodate is relatively expensive, but is required for many sensitive applications such as the synthesis of active pharmaceutical ingredients. These high costs originate from using lead ...dioxide anodes in contemporary electrochemical methods and from expensive starting materials. A direct and cost‐efficient electrochemical synthesis of periodate from iodide, which is less costly and relies on a readily available starting material, is reported. The oxidation is conducted at boron‐doped diamond anodes, which are durable, metal‐free, and nontoxic. The avoidance of lead dioxide ultimately lowers the cost of purification and quality assurance. The electrolytic process was optimized by statistical methods and was scaled up in an electrolysis flow cell that enhanced the space–time yields by a cyclization protocol. An LC‐PDA analytical protocol was established enabling simple quantification of iodide, iodate, and periodate simultaneously with remarkable precision.
The electrochemical synthesis of periodate from iodide at boron‐doped diamond (BDD) anodes was developed, which in contrast to lead dioxide anodes are sustainable and durable. Toxic contaminations are hereby prevented, ultimately reducing the cost of purification. This opens the door for the broad application of periodate for demanding applications, such as the synthesis of active pharmaceutical ingredients.
Ynones are widely used in organic synthesis. Their great success is rooted in their multiple functional groups. This review focus on advance of ynones in published in the decade 2009–2019. Reactions ...triggered by the conjugate addition of nitrogen‐, carbon‐, oxygen‐, boron‐, silicon‐, phosphorus‐, and sulfur‐containing nucleophiles are thoroughly discussed and summarized herein. Multicomponent reactions, rearrangements, cycloadditions, regio‐ and stereoselective synthesis, oxidations, coupling, green chemistry et al. are depicted in detail. We hope that this review will promote future research in this area.
Electrochemical formation of high-energy species such as hydroxyl radicals in aqueous media is inefficient because oxidation of H2O to form O2 is a more thermodynamically favorable reaction. ...Boron-doped diamond (BDD) is widely used as an electrode material for generating •OH radicals because it has a very large kinetic overpotential for O2 production, thus increasing electrochemical efficiency for •OH production. Yet, the underlying mechanisms of O2 and •OH production at diamond electrodes are not well understood. We demonstrate that boron-doped diamond surfaces functionalized with hydrophobic, polyfluorinated molecular ligands (PF-BDD) have significantly higher electrochemical efficiency for •OH production compared with hydrogen-terminated (H-BDD), oxidized (O-BDD), or poly(ethylene ether)-functionalized (E-BDD) boron-doped diamond samples. Our measurements show that •OH production is nearly independent of surface functionalization and pH (pH = 7.4 vs 9.2), indicating that •OH is produced by oxidation of H2O in an outer-sphere electron-transfer process. In contrast, the total electrochemical current, which primarily produces O2, differs strongly between samples with different surface functionalizations, indicating an inner-sphere electron-transfer process. X-ray photoelectron spectroscopy measurements show that although both H-BDD and PF-BDD electrodes are oxidized over time, PF-BDD showed longer stability (≈24 h of use) than H-BDD. This work demonstrates that increasing surface hydrophobicity using perfluorinated ligands selectively inhibits inner-sphere oxidation to O2 and therefore provides a pathway to increased efficiency for formation of •OH via an outer-sphere process. The use of hydrophobic electrodes may be a general approach to increasing selectivity toward outer-sphere electron-transfer processes in aqueous media.
Boron and nitrogen co-doped carbon (BCN) seems to exhibit excellent electrochemical properties very suitable as electrode material for supercapacitor applications. On the other hand, MoS2 possessing ...sheet-like structure proves to be favorable for electrolytic ion intercalation. Here in composites resulting from hydrothermally integrated MoS2 flakes with the BCN have been studied to determine its potency as electrode material for supercapacitor application. Owed to the high packing density of layered MoS2 flakes the as-prepared BCN/MoS2 composite exhibits high volumetric capacitance corresponding to a value of 798 F cm−3 together with the enhanced gravimetric capacitance of 283 F g−1 at the current density of 1 A g−1. Electrochemical studies reveal improved coulombic efficiency, energy, and power densities for the as-prepared BCN/MoS2 composite owed to the established synergy and the presence of interfaces involving two different materials. These results clearly show the usefulness of integration BCN and MoS2 flakes resulting in BCN/MoS2 hybrid as an apt electrode material for supercapacitor application.
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•Composite with integrated BCN and MoS2 shows augmented capacitive properties.•BCN/MoS2 composite shows excellent volumetric capacitance due to high density.•Created interlayer interfaces enhance coulombic efficiency and cyclic stability.•The energy and power density for the BCN/MoS2 composite also undergo a boost.
An ionic covalent–organic framework (ICOF-1 containing sp3 hybridized boron anionic centers formed by spiroborate linkage and dimethylammonium ions) is explored as an ion exchanger for the removal of ...lead (Pb2+) ions from aqueous solution. From molecular simulations, the Pb2+ ions are observed to exchange with the nonframework DMA+ ions in the ICOF-1. At a concentration of 600 ppm, the Pb2+ ions are completely exchanged and reside in the ICOF-1, while the DMA+ ions are in a dynamic equilibrium with the solution. It is revealed that the exchange between Pb2+ and DMA+ is governed by the stronger attraction of Pb2+ with the negatively charged ICOF-1 framework. The radial distribution functions and mean-squared displacements further show that the exchanged Pb2+ ions are in a closer proximity to the ICOF-1 framework with a smaller mobility than DMA+ ions. The simulation study provides microscopic insight into the ion-exchange process between Pb2+ and DMA+, and it suggests that the ICOF-1 might be an intriguing candidate for water purification.
Naphthalene diimide (NDI)-based conjugated polymers have been widely used as the nonfullerene electron acceptor for all-polymer solar cells (all-PSCs), but their low absorption coefficient in the ...near-infrared (NIR) region severely limits the light harvesting ability in solar cells and hence lowers their photovoltaic performance. In this work, two narrow band gap donor–acceptor conjugated polymers based on boron dipyrromethene (BODIPY) as the electron-deficient unit were developed as the electron donor to combine with a NDI-polymer acceptor in order to significantly improve the photoresponse in the NIR region. More importantly, we found that methyl substitution on the BODIPY segment played an important role in charge transport in these polymers. When methyl units were attached to the α-position of BODIPY, the polymer PMBBDT exhibited high-lying energy levels, improved crystallinity, and dramatically high hole mobility compared to the polymer PBBDT without methyl substitution. Consequently, the power conversion efficiencies (PCEs) could be enhanced from 0.32% for PBBDT- to 5.8% for PMBBDT-based all-PSCs, and the photoresponse covered from 300 to 900 nm. Our results demonstrate that methyl-substituted BODIPY-based conjugated polymers are promising candidates to solve the NIR absorption issue in NDI polymers and, therefore, can be potentially used to further boost the PCEs of all-PSCs similar with organic solar cells based on NIR-fused ring electron acceptors.
The presence of the antibiotics in wastewater and drinking water is of growing concern worldwide, thereby an advanced sustainable technology needs to be developed to decontaminate the antibiotics ...from water resources. Herein, a series of novel boron nitrile/cadmium aluminate (BN/CdAl2O4) composites photocatalysts were synthesized by using hydrothermal methodology. Thus synthesized BN/CdAl2O4 composites were tested for the photocatalytic degradation of cefoxitin sodium (CFT) antibiotic in aqueous solution. The spectroscopic analysis confirmed that the morphology, N2 adsorption-desorption, and optical properties of the composites changes as the amount of the BN varies in BN/CdAl2O4 composite. The resulting BN/CdAl2O4 composite with a fraction of 0.2 g BN showed most efficient photocatalytic properties than the pure BN, CdAl2O4 and other BN/CdAl2O4 composites owing to its better light-harvesting properties, higher surface area, and better charge separation properties. The results revealed that the solution pH, irradiation times, and initial CFT concentration in solution controls the photocatalytic process and almost 100% CFT degradation was observed at 15 mg/L concentration within 240 min at pH 7. The results of free radicals scavenging experiments demonstrated that both positive hole and •OH free radical play dominant roles in CFT degradation. The kinetic modeling of CFT photocatalysis process showed better fitting with the first-order kinetic model as compared to the zero-order and second-order kinetic models. This study revealed that BN-0.2/CdAl2O4 composite has better CFT degradation efficiency and excellent recyclability.
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•A series of BN/CdAl2O4 composites photocatalysts were synthesized.•The ratio of BN: CdAl2O4 control the morphology, optical and photocatalytic properties.•Hole and .•OH free radical dominantly roles in cefoxitin sodium degradation•BN/CdAl2O4 composite containing 0.2 g BN showed better light harvesting, and charge separation.
n‐Type Azaacenes Containing B←N Units Min, Yang; Dou, Chuandong; Tian, Hongkun ...
Angewandte Chemie International Edition,
February 12, 2018, Volume:
57, Issue:
7
Journal Article
Peer reviewed
We disclose a novel strategy to design n‐type acenes through the introduction of boron–nitrogen coordination bonds (B←N). We synthesized two azaacenes composed of two B←N units and six/eight linearly ...annelated rings. The B←N unit significantly perturbed the electronic structures of the azaacenes: Unique LUMOs delocalized over the entire acene skeletons and decreased aromaticity of the B←N‐adjacent rings. Most importantly, these B←N‐containing azaacenes exhibited low‐lying LUMO energy levels and high electron affinities, thus leading to n‐type character. The solution‐processed organic field‐effect transistor based on one such azaacene exhibited unipolar n‐type characteristics with an electron mobility of 0.21 cm2 V−1 s−1.
BN there makes all the difference: The introduction of B←N units into azaacenes causes significant perturbations of their electronic structures and properties: Unique LUMOs delocalized over the acene skeletons (see picture) decrease aromaticity of the B←N‐adjacent rings and n‐type character. A solution‐processed organic field‐effect transistor based on one of the azaacenes exhibited unipolar n‐type characteristics and high electron mobility.
Boron‐doped diamond is a powerful and innovative material with outstanding properties, experiencing a strongly emerging interest in the chemical society as electrode material. BDD is generally used ...as a p‐doped semiconductor that can be applied for the disinfection and detoxification of waste‐water since very reactive intermediates can be formed. Besides this destructive performance of BDD electrodes the extraordinary characteristics can also be successfully employed in electro‐synthetic transformations. The performance is usually beyond and much superior to common electrode materials. A key step for the broad interdisciplinary field of application of this particular electrode material is the direct generation of oxyl radicals by electrochemical oxidation. The intention of this mini‐review is to provide the reader a brief overview of the current state of research and to illustrate the different fields of application. The methods applied are critically reviewed.
A shiny future for BDD electrodes in electrosynthetic conversions is anticipated. The review summarizes the state‐of‐the‐art use of diamond electrodes in electrosynthesis. The benefit is clearly found in three fields: unique reactivity, clean conversions, and expanded electrochemical windows.
Capable of mediating efficient transfection and protein production without eliciting innate immune responses, chemically modified mRNA holds great potential to produce paracrine factors at a ...physiologically beneficial level, in a spatiotemporally controlled manner, and with low toxicity. Although highly promising in cardiovascular medicine and wound healing, effects of this emerging therapeutic on the microvasculature and its bioactivity in disease settings remain poorly understood. Here, we longitudinally and comprehensively characterize microvascular responses to AZD8601, a modified mRNA encoding vascular endothelial growth factor A (VEGF-A), in vivo. Using multi-parametric photoacoustic microscopy, we show that intradermal injection of AZD8601 formulated in a biocompatible vehicle results in pronounced, sustained and dose-dependent vasodilation, blood flow upregulation, and neovessel formation, in striking contrast to those induced by recombinant human VEGF-A protein, a non-translatable variant of AZD8601, and citrate/saline vehicle. Moreover, we evaluate the bioactivity of AZD8601 in a mouse model of diabetic wound healing in vivo. Using a boron nanoparticle-based tissue oxygen sensor, we show that sequential dosing of AZD8601 improves vascularization and tissue oxygenation of the wound bed, leading to accelerated re-epithelialization during the early phase of diabetic wound healing.
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