RESUMEN
There exists an interplay between borane and a Lewis base in their adducts. However, studies on these adducts so far have mainly focused on the different reactions of B-H bonds with limited attention given to the influence of borane on the chemistry of the Lewis base, except for BF3 and BAr3. Herein, we have synthesized novel borane adducts with pyridine derivatives, Py·B3H7, in which the coordination of B3H7 efficiently achieved the intra-molecular charge transfer. The strong B-N bond in these adducts resulted in the formation of stable dearomatic intermediates of pyridine derivatives, confirmed by 1H and 11B NMR spectroscopy, from which different reactions have transpired to realize C(sp3)-H and C(sp2)-H functionalization under mild conditions. The B3H7 pyridine derivatives are stable and do not dissociate or decompose during the reaction process. The high stability of the B-N bond makes this method a good option for boron-containing drugs with potential for use in boron neutron capture therapy (BNCT).
RESUMEN
Polyhedral boranes have potential applications in medicine and material science due to their unique structure and stability. However, tedious and low-yield synthetic methods limited their application. Herein, we have developed a facile large-scale synthetic method for M2[B12H12] (M = Na, K) by the reaction of MBH4 with N,N-dipropylaniline borane in diglyme at 120 or 140 °C in up to 88% yield. The mechanistic studies indicated that intermediates, such as [B3H8]- and [B9H14]-, were formed in the formation process of [B12H12]2- anion, similar to previously reported. The formation of B2H6 from the N,N-dipropylaniline borane adducts is most important. The developed method avoided using toxic materials, with high yield, easily scaled up, raw materials are readily available. Additionally, the starting material, N,N-dipropylaniline, could be repeatedly used at least three times with similar yields, which is an economical way to facilitate industrial synthesis. It is believed that this method will support further application of Na2[B12H12] and K2[B12H12] as solid electrolytes for an all-solid-state batteries.
RESUMEN
Improving the activity of uricase and lowering its immunogenicity remain significant challenges in the enzyme replacement management of hyperuricemia and related inflammatory diseases. Herein, an immunogenicity-masking strategy based on engineered red blood cells (RBCs) was developed for effective uricase delivery against both hyperuricemia and gout. The dynamic membrane of RBCs enabled high resistance to protease inactivation and hydrogen peroxide accumulation. Benefiting from these advantages, a single infusion of RBC-loaded uricase (Uri@RBC) performed prolonged blood circulation and sustained hyperuricemia management. Importantly, RBCs masked the immunogenicity of uricase, leading to the maintenance of UA-lowering performance after repeated infusion through reduced antibody-mediated macrophage clearance. In an acute gout model, Uri@RBC profoundly alleviated joint edema and inflammation with minimal systemic toxicity. This study supports the employment of immunogenicity-masking tools for efficient and safe enzyme delivery, and this strategy may be leveraged to improve the usefulness of enzyme replacement therapies for managing a wide range of inflammatory diseases.
Asunto(s)
Eritrocitos , Gota , Hiperuricemia , Urato Oxidasa , Urato Oxidasa/administración & dosificación , Urato Oxidasa/uso terapéutico , Urato Oxidasa/inmunología , Hiperuricemia/tratamiento farmacológico , Hiperuricemia/inmunología , Animales , Gota/inmunología , Eritrocitos/inmunología , Masculino , Humanos , Ácido Úrico/sangre , Ratones , Ratones Endogámicos C57BLRESUMEN
Solid-state sodium metal batteries have been extensively investigated because of their potential to improve safety, cost-effectiveness, and energy density. The development of such batteries urgently required a solid-state electrolyte with fast Na-ion conduction and favorable interfacial compatibility. Herein, the progress on developing the NaB3H8 solid-state electrolytes is reported, which show a liquid-like ionic conductivity of 0.05 S cm-1 at 56 °C with an activation energy of 0.35 eV after an order-disorder phase transformation, matching or surpassing the best single-anion hydridoborate conductors investigated up to now. The steady polarization voltage and significantly decreased resistance are achieved in the symmetric Na/NaB3H8/Na cell, indicating the great electrochemical stability and favorable interfacial contact with the Na metal of NaB3H8. Furthermore, a Na/NaB3H8/TiS2 battery, the first high-rate (up to 1 C) solid-state sodium metal battery using the single-anion hydridoborate electrolyte, is demonstrated, which exhibits superior rate capability (168.2 mAh g-1 at 0.1 C and 141.2 mAh g-1 at 1 C) and long-term cycling stability (70.9% capacity retention at 1 C after 300 cycles) at 30 °C. This work may present a new possibility to solve the interfacial limitations and find a new group of solid-state electrolytes for high-performance sodium metal batteries.
RESUMEN
The BCN-heterocyclic B-N chain compounds, the sodium and potassium salts of 3 and 4 anions (Na3, Na4, and K4), were synthesized by reactions of ethane 1,2-diamineborane (BH3NH2CH2CH2NH2BH3, 1) and propane 1,2-diamineborane (BH3NH2CH2CH2CH2NH2BH3, 2) with MH (M = Na and K). Then, the neutral B-N chain compounds 5 and 6 were prepared with dehydrogenation of [NH4]3 and [NH4]4, formed by metathesis reactions of Na3 and Na4 with NH4Cl or NH4SCN, respectively. Compounds 7 and 8, analog 5, were also prepared using pyridine and 4-methoxypyridine instead of NH3 in 5. These synthesized compounds were characterized spectroscopically, and the singe-crystal structures of the Na3·18-crown-6 and K4·18-crown-6 adducts were determined. Furthermore, the reactions of Na3 and Na4 with cationic B-N chain compounds, [NH3BH2NH3]Cl and [NH3BH2NH2BH2NH3]Cl, could not form longer BCN-heterocyclic B-N chain. The solubility of metal hydrides, the ability for proton abstracting, the basicity of Lewis bases, and the chelate effect may influence these reactions even though the reaction mechanism is not fully understood.
RESUMEN
The reduction mechanism of aldehyde/ketones with M(BH4)n is not fully understood, even though the hydroboration mechanism of weak Lewis base borane complexes is known to involve a four-membered ring transition state. Herein, the reduction mechanism of M(BH4)n in aprotic solvents has been elucidated for a six-membered ring, in which hydride transfer to the C atom from the B atom, formation of an L·BH3 adduct, and disproportionation of (BH3(OR)-) borane are involved. The metal cations and solvents participate in and significantly influence the reaction procedure. We believe that this mechanistic study would provide a further reference for the application of M(BH4)n in organic reactions.
RESUMEN
A green and practical protocol of defluoroborylation of polyfluoroarenes with stable and readily accessible NHC-borane was developed, using 1,2-diphenyldisulfane as a hydrogen atom transfer (HAT) and single electron transfer (SET) reagent precursor under visible-light irradiation, leading to the concise formation of value-added fluorinated organoboron scaffolds. Mechanism studies revealed the method underwent a boryl radical addition reaction with polyfluoroarene, followed by successive single electron transfer pathways and defluorination of the C-F bond to offer the targeted product. This unprecedented platform relies on 1,2-diphenyldisulfane and base without using expensive photocatalysts, highlighting the methodology has promising application value to prepare borylated polyfluoroarene compounds.
RESUMEN
All-solid-state potassium metal batteries have been considered promising candidates for large-scale energy storage because of abundance and wide availability of K resources, elimination of flammable liquid organic electrolytes, and incorporation of high-capacity K metal anode. However, unideal K-ion conductivities of most reported K-ion solid electrolytes have restricted the development of these batteries. Herein, a novel K2B10H10·CO(NH2)2 complex is reported, forming by incorporating urea into K2B10H10, to achieve an enhanced K-ion conductivity. The crystal structure of K2B10H10·CO(NH2)2 was determined as a monoclinic lattice with the space group of C2/c (No. 15). K2B10H10·CO(NH2)2 delivers an ionic conductivity of 2.7 × 10-8 S cm-1 at 25 °C, and reaching 1.3 × 10-4 S cm-1 at 80 °C, which is about 4 orders of magnitude higher than that of K2B10H10. One possible reason is the anion expansion in size due to the presence of dihydrogen bonds in K2B10H10·CO(NH2)2, resulting in an increase in the K-H bond distance and the electrostatic potential, thereby enhancing the mobility of K+. The K-ion conductivity is also higher than those of most hydridoborate-based K-ion conductors reported. Besides, K2B10H10·CO(NH2)2 reveals a wide electrochemical stability window and remarkable interface compatibility with K metal electrodes, suggesting a promising electrolyte for all-solid-state K metal batteries.
RESUMEN
All-solid-state sodium metal batteries are promising for large-scale energy storage applications owing to their intrinsic safety and cost-effectiveness. However, they generally suffer from sodium dendrite growth or rapid capacity fading, especially at high rates, mainly due to poor wettability, sluggish ionic transport, or low interfacial stability of the solid electrolytes. Herein, we report a novel composite, NaB3H8 â xNH3@NaB3H8 (x<1), as a new class of solid electrolyte for high-rate batteries. NaB3H8 â xNH3@NaB3H8 is obtained from the sticky NaB3H8 â NH3 after removal of NH3 partially at room temperature. It delivers an ionic conductivity of 0.84â mS cm-1 at 25 °C and reaches 20.64â mS cm-1 at 45 °C after an order-disorder phase transformation. It also reveals a good capability of dendrite suppression and remarkable stability against sodium metal. These performances enable the all-solid-state Na//TiS2 battery with a high capacity of 232.4â mAh g-1 (97.2 % of theoretical capacity) and long-term cycling stability at 1â C. Notably, this battery shows superior long-life cycling stability even at 5 and 10â C, which has been rarely reported in all-solid-state sodium metal batteries. This work opens a new group of solid electrolytes, contributing to fast-charging or high-power-density sodium metal batteries.
RESUMEN
The Friedel-Crafts alkylation of arenes is an important part of electrophilic aromatic substitution reactions. However, the reactivity of arenes is weakened by electron-withdrawing substituents, leading to limited substrate scopes and applications. Herein, we developed an efficient HOTf-promoted Friedel-Crafts alkylation reaction of broad arenes with α-aryl-α-diazoesters under metal-free and solvent-free conditions.
RESUMEN
A highly efficient Pd-catalyzed B(9)-H/B(9)-H oxidative dehydrogenation coupling of carboranes to synthesize 9,9'-bis-o-carboranes has been developed. The properties and derivatization of 9,9'-bis-o-carborane were also examined, which provided diverse bis-o-carborane derivatives and bis-nido-carborane.
RESUMEN
An efficient method for the synthesis of M2B10H14 (M = Na and K) has been developed. The two possible formation mechanisms of the B10H142- anion are proposed, in which the NH2BH3- anion acts as a proton abstractor and a hydride donor. Furthermore, the B10H13- and B10H15- intermediates were detected.
RESUMEN
Nickel chloride and thiolate complexes supported by benzene-pyridine-based nonsymmetrical PCN pincer ligands, [2-(tBu2PO)-6-(2-pyrindinyl-4-R)-C6H3]NiX (R = H, CH3, CF3; X = Cl, SH, SPh), were synthesized and fully characterized. The structures of these complexes and the catalytic reactivity of the chloride complexes were investigated along with the related POCOP counterparts [2,6-(tBu2PO)2C6H3]NiX (X = Cl, SH). It was found that the composition and substitution of the pincer backbone evidently influence the structures and catalytic reactivity. The Ni-P and Ni-Cipso bond lengths in the PCN complexes are significantly shorter than those in the POCOP complex. The Ni-Cl and Ni-S bond lengths in the PCN complexes are longer than those in the POCOP complexes. An electron rich pyrindinyl ring in the PCN complexes makes the Ni-Cl bond longer. The Ni-N bond length is more sensitive to the auxiliary ligand compared with the Ni-P bond length in the PCN complexes. The PCN chloride complexes were found to be active catalysts for selective hydration of nitriles to primary amides in the presence of NaOH at 80 °C and the catalytic activity increases with the increase of electron richness of the pyridinyl ring. However, the corresponding POCOP counterpart is inactive under the same conditions.
RESUMEN
Osteoarthritis (OA) is a common and complex inflammatory disorder that is frequently compounded by cartilage degradation, synovial inflammation, and osteophyte formation. Damaged chondrocytes release multiple danger mediators that exacerbate synovial inflammation and accelerate the progression to OA. Conventional treatments targeting only a single mediator of OA have failed to achieve a strong therapeutic effect. Addressing the crucial role of multiple danger mediators in OA progression, we prepared polyethylenimine (PEI)-functionalized diselenide-bridged mesoporous silica nanoparticles (MSN-PEI) with cell-free DNA (cfDNA)-binding and anti-oxidative properties. In models of surgery-induced and collagenase-induced arthritis, we showed that these cationic nanoparticles attenuated cartilage degradation and provided strong chondroprotection against joint damage. Mechanistically, multiple target blockades alleviated oxidative stress and dampened cfDNA-induced inflammation by suppressing the M1 polarization of macrophages. This study suggests a beneficial direction for targeting multiple danger mediators in the treatment of intractable arthritis.
Asunto(s)
Ácidos Nucleicos Libres de Células , Nanopartículas , Osteoartritis , Humanos , Dióxido de Silicio/uso terapéutico , Osteoartritis/tratamiento farmacológico , Osteoartritis/metabolismo , Inflamación/tratamiento farmacológico , Inflamación/metabolismo , Condrocitos/metabolismo , Nanopartículas/química , Ácidos Nucleicos Libres de Células/metabolismo , Ácidos Nucleicos Libres de Células/farmacología , Ácidos Nucleicos Libres de Células/uso terapéuticoRESUMEN
The activation of molecular hydrogen is a key process in catalysis. Here, we demonstrate how polyoxometalate (POM)-based heterogeneous compounds functionalized with Platinum particles activate H2 by synergism between a hydrogen spillover mechanism and electron-proton transfer by the POM. This interplay facilitates the selective catalytic reduction of olefins and nitroarenes with high functional group tolerance. A family of polyoxotungstates covalently functionalized with boronic acids is reported. In the solid-state, the compounds are held together by non-covalent interactions (π-π stacking and hydrogen bonding). The resulting heterogeneous nanoscale particles form stable colloidal dispersions in acetonitrile and can be surface-functionalized with platinum nanoparticles by in situ photoreduction. The resulting materials show excellent catalytic activity in hydrogenation of olefins and nitrobenzene derivatives under mild conditions (1â bar H2 and room temperature).
RESUMEN
In this work, we developed a facile and controllable electrophilic aromatic nitration method with commercially available 68% HNO3 as the nitrating reagent and trifluoromethanesulfonic acid (HOTf) as the catalyst in hexafluoroisopropanol or under solvent-free conditions. The electrophilic nitration products of different arenes can be obtained in almost quantitative yields by tuning the loading of HOTf. The strong acidity and water absorbing property of HOTf allowed this transformation to reach completion in a short time at room temperature.
RESUMEN
Recent research has attracted considerable attention toward N-heterocyclic carbene-coordinated boranes (NHC-borane) and their B-substituted derivatives because of their unique characteristics. In the present work, we focused on the syntheses, structures, and reactivities of such types of amine complexes, [NHC·BH2NH3]X ((NHC = IPr (1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) and IMe (1,3-dimethylimidazol-2-ylidene); X = Cl, I, OTf). We have developed a synthetic method to access NHC·BH2NH2 through the reaction of NaH with [IPr·BH2NH3]I, which was synthesized by the reaction of IPr·BH2I with NH3. As a Lewis base, NHC·BH2NH2 could further react with HCl or HOTf to produce the corresponding salts of [IPr·BH2NH3]+. IPr·BH2NH2BH2X (X = Cl, I) were synthesized by the reaction of HCl/I2 with IPr·BH2NH2BH3 and then converted to [IPr·BH2NH2BH2·IPr]X (X = Cl, I) by reacting with IPr. The IMe-coordinated boranes reacted quite similarly. The preliminary results revealed that the introduction of the NHC molecule has a considerable impact on the solubility and reactivities of aminoboranes.
RESUMEN
Boron dipyrromethene (also known as bodipy), as a class of versatile and robust fluorophores and a structural analogue of porphyrins, has received a great deal of interests in the field of light-harvesting and energy-transfer processes. However, the fabrication of bodipy monomers into metal-organic frameworks (MOFs) and the exploitation of their potential still lags behind the porphyrin MOFs. In this work, two bodipy-based MOFs, BMOF 1D with 1D chain structure and BMOF 2D with 2D layer structure, were assembled by using dicarboxyl-functionalized bodipy ligands. BMOF 1D can also be converted to BMOF 2D by inserting additional ligands into BMOF 1D to cross-link the adjacent chains into the rhombic grid layer. During this process, spontaneous exfoliation occurred simultaneously and resulted in the formation of several hundred nanometer thickness BMOF 2D (nBMOF 2D), which can be further exfoliated into one-layer MOF nanosheets (BMON 2D) by using the ultrasonic liquid exfoliation method in a high yield. Featuring the distinct bodipy scaffolds in the porous frameworks, both BMOF 2D and BMON 2D displayed high reactivity and recyclability in the photocatalytic inverse hydroboration and cross-dehydrogenative coupling reactions to afford α-amino organoborons and α-amino amides in moderate to high yields. This work not only highlights the cascade utilization of ligand installation and ultrasonic liquid exfoliation methods to provide the single-layer MOF sheets in high yields but also advances the bodipy-based MOFs as a new type of heterogeneous photocatalysts in the forging of C-B and C-C bonds driven by visible light.
RESUMEN
In order to develop efficient protocols for CO2 reduction with less expensive and more convenient hydrogen sources, the catalytic reactivities of group 10 metal hydride complexes supported by a PNCNP pincer ligand, [2,6-(tBu2PNH)2C6H3]MH (M = Ni, 1a; Pd, 1b; Pt, 1c), against the hydroboration of CO2 with NH3·BH3 and NaBH4 have been explored. Both 1a and 1b readily react with CO2 at room temperature to form the corresponding formato complexes, [2,6-(tBu2PNH)2C6H3]MOC(O)H (M = Ni, 2a; Pd, 2b), in nearly quantitative yields. Treatment of NH3·BH3 with CO2 (1 atm) in 1,4-dioxane or THF at room temperature in the presence of 0.05-1.0 mol % of 1b followed by hydrolysis of the resulting mixtures produces formic acid in 105-186% yields, and initial turnover frequencies of up to 2000 h-1 are observed. In the presence of 1.0 mol % of 1b, NaBH4 reacts with CO2 (1 atm) in THF at room temperature to form NaB[OC(O)H]4 (3) in 87% isolated yield. In situ NMR spectroscopy indicates that the reactions proceed through the insertion of the CâO bond in CO2 into the Pd-H bond in 1b to form 2b, which sequentially reacts with the hydrides in NH3·BH3 or NaBH4 to produce boron formato species and regenerate 1b. This work represents one of the rare examples of catalytic transfer hydrogenation of CO2 with NH3·BH3 to the formic acid level under very mild conditions without any additives and also the first example of 4 equiv of CO2 uptake by NaBH4 in a reaction.
RESUMEN
Herein, we present a chemically robust and efficient synthesis route for B(9)-OH-o-carboranes by the oxidation of o-carboranes with commercially available 68% HNO3 under the assistance of trifluoromethanesulfonic acid (HOTf) and hexafluoroisopropanol (HFIP). The reaction is highly efficient with a wide scope of carboranes, and the selectivity of B(9)/B(8) is up to 98:2. The success of this transformation relies on the strong electrophilicity and oxidizability of HNO3, promoted through hydrogen bonds of the Brønsted acid HOTf and the solvent HFIP. Mechanism studies reveal that the oxidation of o-carborane involves an initial electrophilic attack of HNO3 to the hydrogen atom at the most electronegative B(9) of o-carborane. In this transformation, the hydrogen atom of the B-H bond is the nucleophilic site, which is different from the electrophilic substitution reaction, where the boron atom is the nucleophilic site. Therefore, this is an oxidation-reduction reaction of o-carborane under mild conditions in which N(V) â N(III) and H(-I) â H(I). The derivatization of 9-OH-o-carborane was further examined, and the carboranyl group was successfully introduced to an amino acid, polyethylene glycol, biotin, deoxyuridine, and saccharide. Undoubtedly, this approach provides a selective way for the rapid incorporation of carborane moieties into small molecules for application in boron neutron capture therapy, which requires the targeted delivery of boron-rich groups.