N-(6-Methyl-2-pyridyl)acrylamide: a case of amide hydrolysis without the assistance of acid or base in the synthesis of water-driven H-bonded polymeric chains

Amide hydrolysis of N-(6-methyl-2-pyridyl)acrylamide without the assistance of either acid or base produces the aminopyridinium carboxylate salt at low or room temperature. The carboxylate ion and the free amine functionalities are cooperatively involved in hydrogen bonding with lattice water to form a new hydrogen-bonded polymeric chain.     

The Effect of Platinum on Stability of the B2O3/TiO2-ZrO2 Catalyst for Beckmann Rearrangement of Cyclohexanone Oxime

It has been well illustrated that the rapid catalyst deactivation with time is the most serious limitation of vapor phase approach to the production of ε-caprolactam from cyclohexanone oxime (CHO) (Scheme 1), and is a common problem with all catalyst typ…     

Preparation of Trace Fe2P Modified N,P Co-doped Carbon Materials and their Application to Hydrogen Peroxide Detection

The determination of hydrogen peroxide (H₂O₂) based on electrochemical sensors is highly attractive in the fields of environmental monitoring and biosensing, however development of non-precious metal-based electrocatalysts with high performances remains challenging. Here, a new non-enzymatic H₂O₂ sensor has been reported by using Fe₂P modified N,P co-doped carbon (Fe₂P/NP-C) materials as sensing materials. Fe₂P/NP-C materials were synthesized by pyrolysis of polydopamine coating Fe-based coordination polymer nanoparticles, which were obtained by direct mixing FeCl₃ and sodium hexametaphosphate at room temperature. The electrochemical tests display that Fe₂P/NP-C-based non-enzymatic H₂O₂ sensor exhibited detection limit of 60 μM and linear range from 0.1 mM to 1 mM, respectively. This work presents a new avenue to design of non-precious metal-based electrocatalysts for chemical sensing and biosensing applications.     

Conductive Microporous Covalent Triazine‐Based Framework for High‐Performance Electrochemical Capacitive Energy Storage

Nitrogen‐enriched porous nanocarbon, graphene, and conductive polymers attract increasing attention for application in supercapacitors. However, electrode materials with a large specific surface area (SSA) and a high nitrogen doping concentration, which is needed for excellent supercapacitors, has not been achieved thus far. Herein, we developed a class of tetracyanoquinodimethane‐derived conductive microporous covalent triazine‐based frameworks (TCNQ‐CTFs) with both high nitrogen content (>8 %) and large SSA (>3600 m² g^?1). These CTFs exhibited excellent specific capacitances with the highest value exceeding 380 F g^?1, considerable energy density of 42.8 Wh kg^?1, and remarkable cycling stability without any capacitance degradation after 10 000 cycles. This class of CTFs should hold a great potential as high‐performance electrode material for electrochemical energy‐storage systems.     

Simultaneous Fenton‐like Ion Delivery and Glutathione Depletion by MnO2‐Based Nanoagent to Enhance Chemodynamic Therapy

Chemodynamic therapy (CDT) utilizes iron‐initiated Fenton chemistry to destroy tumor cells by converting endogenous H₂O₂ into the highly toxic hydroxyl radical (^.OH). There is a paucity of Fenton‐like metal‐based CDT agents. Intracellular glutathione (GSH) with ^.OH scavenging ability greatly reduces CDT efficacy. A self‐reinforcing CDT nanoagent based on MnO₂ is reported that has both Fenton‐like Mn²⁺ delivery and GSH depletion properties. In the presence of HCO₃^?, which is abundant in the physiological medium, Mn²⁺ exerts Fenton‐like activity to generate ^.OH from H₂O₂. Upon uptake of MnO₂‐coated mesoporous silica nanoparticles (MS@MnO₂ NPs) by cancer cells, the MnO₂ shell undergoes a redox reaction with GSH to form glutathione disulfide and Mn²⁺, resulting in GSH depletion‐enhanced CDT. This, together with the GSH‐activated MRI contrast effect and dissociation of MnO₂, allows MS@MnO₂ NPs to achieve MRI‐monitored chemo–chemodynamic combination therapy.     

Copper-catalyzed radical/radical cross-coupling of ketoxime carboxylates with 4-hydroxycoumarins: A novel synthesis of furo[3,2-c]-coumarins

A novel and efficient strategy for the synthesis of furo[3,2-c]coumarins has been developed via copper-catalyzed radical/radical cross-coupling of ketoxime carboxylates with 4-hydroxycoumarins. This redox-neutral reaction allows smooth and selective synthesis of 2-substituted, 3-substituted, 2,3-disubstituted and 2,3-fused polycyclic furo[3,2-c]coumarins.     

Spectrophotometric determination of tetracyclines in pharmaceutical preparations, with uranyl acetate

Uranyl acetate is proposed as a reagent for the spectrophotometric determination of the tetracycline group of antibiotics. The reagent forms orange-red 1:1 complexes with the drugs in N,N-dimethylformamide medium. The complexes show absorption maxima at 414, 406, 419, 405 and 402 nm for tetracycline hydrochloride (TCH), oxytetracycline hydrochloride (OTCH), chlortetracycline hydrochloride (CTCH), doxycycline hydrochloride (DCH) and methacycline hydrochloride (MCH), respectively. Beer's law is valid over the concentration ranges 0–115, 0–120, 0–125, 0–135 and 0–110 μg/ml for TCH, OTCH, CTCH, DCH and MCH, respectively.     

Influence of cation on the cellulose dissolution investigated by MD simulation and experiments

Cellulose is the most abundant natural polymer on the earth, and effective solvents are essential for its wide application. Among various solvents such as alkali/urea or ionic liquids, cations all play a very important role on the cellulose dissolution. In this work, the influence of cation on the cellulose dissolution in alkali/urea via a cooling process was investigated with a combination of MD simulation and experiments, including differential scanning calorimetry (DSC) and NMR diffusometry (PFG-SE NMR). The results of DSC proved that the dissolution of cellulose in both solvents was a process within a temperature range, starting at above 0 °C and completing at low temperature (?5 °C for LiOH/urea and ?20 °C for NaOH/urea), indicating the necessity of low temperature for the cellulose dissolution. Molecular dynamic (MD) simulation suggested that the electrostatic force between OH^? and cellulose dominated the inter-molecular interactions. In our findings, Li⁺ could penetrate closer to cellulose, and displayed stronger electrostatic interaction with the biomacromolecule than Na⁺, thus possessed a greater “stabilizing” effect on the OH^?/cellulose interaction. PFG-SE NMR demonstrated a more significant binding fraction of Li⁺ than Na⁺ to cellulose, which was consistent with MD. These results indicated that the direct interactions existed between the cations and cellulose, and Li⁺ exhibited stronger interaction with cellulose, leading to stronger dissolving power.