Monthly Archives: January 2024

Synthesis and reactivity of a dialkyl‐2H‐1,2‐phosphasiliren‐3‐olate

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Synthesis and reactivity of a dialkyl-2H-1,2-phosphasiliren-3-olate

A heterocycle containing phosphorus, known as dialkyl-2H-1,2-phosphasiliren-3-olate is synthesized through the reaction of dialkylsilylene and sodium phosphaethynolate (NaOCP). The theoretical studies are identified two nucleophilic centres located on the phosphorus (P) and oxygen (O) atoms, respectively. The electrophilic reactivities involving R3SiCl, Me2SO4 and acyl chlorides are also conducted occurring at the oxygen atom.


Abstract

A heterocycle containing phosphorus, known as dialkyl-2H-1,2-phosphasiliren-3-olate 2, is synthesized through the reaction of dialkylsilylene 1 and sodium phosphaethynolate (NaOCP) in a high yield at ambient conditions. The structure of 2 is determined by single-crystal X-ray diffraction and multinuclear NMR spectroscopy. The theoretical studies are identified two nucleophilic centres located on the phosphorus (P) and oxygen (O) atoms, respectively. According to WBIs and the crystal characterization analyses, both the C−P and C−O bonds in the C−Si-P three-membered ring have significant double bond character. Reactions involving R3SiCl and Me2SO4 with 2 at room temperature are also conducted at room temperature. The nucleophilic substitution reaction can also occur on oxygen atom of 2, and yield ring-retaining products 3 and 4 a–4 c, respectively. When acyl chlorides are employed as electrophiles, the derivatives of (silylmethylidyne)phosphane, 6 a–6 c, are produced as a result of the substitution of the oxygen atom.

Ethylenediamine Salt Enhances the Solubility and Dissolution of Flurbiprofen

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Ethylenediamine Salt Enhances the Solubility and Dissolution of Flurbiprofen

A novel flurbiprofen-ethylenediamine salt (FLU-EDA) was successfully prepared via solvent crystallization. Its crystal structure was determined via single-crystal X-ray diffraction (SXRD). Further, the physicochemical properties of FLU-EDA salt were characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FT-IR). The solubility and intrinsic dissolution rate (IDR) of FLU-EDA salt in water were investigated.


Abstract

Drugs that are poorly soluble in water are difficult to absorb orally, resulting in low bioavailability. Flurbiprofen (FLU) is an arylpropionic acid nonsteroidal anti-inflammatory drug belonging to BCS class II, with low water solubility. In this study, a novel flurbiprofen-ethylenediamine salt (FLU-EDA) was successfully prepared via solvent crystallization. Its crystal structure was determined via single-crystal X-ray diffraction (SXRD). Further, the physicochemical properties of FLU-EDA salt were characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FT-IR). The solubility and intrinsic dissolution rate (IDR) of FLU-EDA salt in water were investigated. The results showed that compared with FLU, the solubility and IDR of FLU-EDA salt increased by 57-fold and 32-fold, respectively. This indicates that FLU-EDA salt can significantly enhance the solubility and dissolution rate of flurbiprofen in water. This study provides basic data and theory for the development of new formulations of flurbiprofen.

Preparation of green high‐performance biomass‐derived hard carbon materials from bamboo powder waste

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Preparation of green high-performance biomass-derived hard carbon materials from bamboo powder waste

This study used pre-treatment and template carbonization methods to extract a hard carbon material from a large amount of discarded biomass in bamboo powder waste. Template activation method produces rich and uniform pore structures that are beneficial for sodium storage.


Abstract

Efficient energy storage systems are crucial for the optimal utilization of renewable energy. Sodium-ion batteries (SIBs) are considered potential substitutes for next-generation low-cost energy storage systems due to the low cost and abundance of sodium resources. However, the industrialization of SIBs faces a great challenge in terms of the anode. Hard carbon could be a promising anode material due to its high capacity and low cost which originates from biomass. This study used pre-treatment and template carbonization methods to extract a hard carbon material from a large amount of discarded biomass in bamboo powder waste. This material has a good initial Coulombic efficiency of 78.6 % and good cycling stability when applied to sodium ion batteries.Typically, the optimal hard carbon material is used as the anode to prepare sodium ion battery prototypes to demonstrate their potential applications. The anode exhibited excellent sodium storage performance with a reversible capacity of 303 mAh ⋅ g−1 at 1 C rate and good cycling performance, retaining 92.0 % of its capacity after 100 cycles. These results demonstrate that BPPHC is a promising candidate for anode material in sodium-ion batteries. This work suggests that bamboo powder could be a low-cost anode material for SIBs.

Crystallization of the Fundamental Tetracyanamidometallates Li4[Si(CN2)4] and Li4[Ge(CN2)4] from Polymeric Li‐T‐(NCN)‐I Precursors (T=Si, Ge)

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Crystallization of the Fundamental Tetracyanamidometallates Li4[Si(CN2)4] and Li4[Ge(CN2)4] from Polymeric Li-T-(NCN)-I Precursors (T=Si, Ge)

Solid-state reactions between SiI4 (or GeI4) and Li2(CN2) pass through amorphous stages to finally yield the unprecedented Li4[Si(CN2)4] (or Li4[Ge(CN2)4]). Tetracyanamidometallate anions may be combined with various cations of the PSE.


Abstract

The tetracyanamidometallates Li4[T(CN2)4] with T=Si, Ge were prepared by solid-state metathesis (SSM) reactions between TI4 and Li2(CN2). The new compounds Li4[T(CN2)4] are obtained as crystalline phases in high yields and represent the most basic examples of the family of tetracyanamidometallates. The formation of these compounds, via SiI4 and Li2(CN2), is analyzed by means of differential scanning calorimetry (DSC). The [Si(CN2)4]4− ion in the structure of Li4[Si(CN2)4] can be considered an analogue to the [SiO4]4− ion in Li4SiO4. The crystal structures of Li4[T(CN2)4] were solved and refined isotypically on the basis of single-crystal X-ray diffraction data in the space group C2/c, and further characterized by infrared and solid-state NMR techniques.

Synthesis and properties of RNA constrained by a 2’‐O‐disulfide bridge

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Synthesis and properties of RNA constrained by a 2’-O-disulfide bridge

This work describes the synthesis and properties of oligoribonucleotides containing diethylene (DEE) and dipropylene (DPE) disulfide bridge between two adjacent uridines.


Abstract

We recently reported the properties of RNA hairpins constrained by a dimethylene (DME) disulfide (S−S) linker incorporated between two adjacent nucleosides in the loop and showed that this linker locked the hairpin conformation thus disturbing the duplex/hairpin equilibrium. We have now investigated the influence of the length of the linker and synthesized oligoribonucleotides containing diethylene (DEE) and dipropylene (DPE) S−S bridges. This was achieved via the preparation of building blocks, namely 2′-O-acetylthioethyl (2′-O-AcSE) and 2′-O-acetylthiopropyl (2′-O-AcSP) uridine phosphoramidites, which were successfully incorporated into RNA sequences. Thermal denaturation analysis revealed that the DEE and DPE disulfide bridges destabilize RNA duplexes but do not disrupt the hairpin conformation. Furthermore, our investigation of the duplex/hairpin equilibrium indicated that sequences modified with DME and DEE S−S linkers predominantly lock the hairpin form, whereas the DPE S−S linker provides flexibility. These findings highlight the potential of S−S linkers to study RNA interactions.

Carbon Nanofibers‐Based Anodes for Potassium‐Ion Battery

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Carbon Nanofibers-Based Anodes for Potassium-Ion Battery

This article explores the key issues faced by carbon nanofibers (CNFs)-based materials and future development directions, and proposes improvement suggestions for providing new ideas for the development of CNFs-based materials.


Abstract

In recent years, with the global warming getting worse and increasing demand for energy, countries around the world are trying to develop new energy storage technologies to solve this problem. Currently, potassium-ion batteries (PIBs) have attracted tremendous attention from researchers as low-cost and high-performance energy storage devices. However, due to the huge ionic radius of K+, PIBs face significant volume expansion during cycling, which can easily lead to the collapse of electrode structures. In addition, the poor diffusion kinetics of K+ seriously affect the electrochemical performance of the battery. Carbon nanofibers (CNFs)-based materials (including CNFs, metal/CNFs composites, chalcogenide/CNFs composites, and other CNFs-based materials) are widely used as PIBs electrode anode materials due to their three-dimensional conductive network, heteroatom doping and excellent mechanical properties. This review discusses in detail the research progress of CNFs-based materials in PIBs, including material preparation, structural design, and performance optimization. On this basis, this article explores the key issues faced by CNFs-based materials and future development directions, and proposes improvement suggestions for providing new ideas for the development of CNFs-based materials.

Carbonylation of Boranes – A Computational Study

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Carbonylation of Boranes – A Computational Study

Despite long time assumed as direct intramolecular migratory insertions, the two last of the three alkyl group migrations after alkylborane carbonylation with carbon monoxide are shown to proceed either through activated dimeric species or catalyzed by the final product, as the only low barrier possible pathways, the latter leading to scarcely aromatic boroxines.


Abstract

The classical simple picture of stepwise B-to-C migratory insertion of all three alkyl groups in the carbonylation reaction of trialkyl boranes with CO was shown not to be correct, except for the first alkyl group shift affording an acyl borane. The second and third direct alkyl shifts turned out to be kinetically hampered due to the non-activated character of the B−C bond in electron-poor B atoms. The latter can only be achieved by either the autocatalytic action of the final alkyl boron oxide or by formation of dimeric species with weakened B-alkyl bonds at borate centres. Both thermodynamic and several NICS-related parameters pointed to scarce, even “negative”, aromatic character for boroxines, the final cyclotrimerization products of alkyl-boron oxides.