Magnetically Retrievable Nanocomposite Based on Thiosemicarbazide–Formaldehyde Resin as a Versatile Nucleophilic Scavenger

A magnetically retrievable nanocomposite was prepared by in situ polycondensation and entrapment of iron oxide nanoparticles. This material was found to be efficient in trapping excess electrophilic reagents such as carbonyl compounds, acid chlorides and isothiocyanates. Advantages of the new scavenger include facile preparation, high loading capacity, low cost, satisfactory swelling properties in polar solvents, and convenient magnetic recovery

Synthesis of Highly Branched Polyethylene Using “Sandwich” (8‑<i>p</i>‑Tolyl naphthyl α‑diimine)nickel(II) Catalysts

Nickel­(II) α-diimine dibromide complexes incorporating 8-<i>p</i>-tolylnaphthylimino groups have been prepared and used for ethylene polymerization by activation with modified methylalumoxane (MMAO). These catalysts possess increased axial bulk relative to standard diimine-nickel complexes, resulting in lower rates of chain transfer relative to chain propagation rates and thus higher polymer molecular weights and narrower PDIs. They yield the most highly branched PE produced by Ni catalysts seen to date. The easy synthesis of 8-aryl-1-naphthylamines provides ready access to a new class of α-diimine-based nickel catalysts in which the 8-substituent is ideally positioned to provide steric bulk at the axial sites

Heterostructure Made of Multilayer MXene (Ti₃C₂T_<i>x</i>) and Vertically Grown CoFe₂O₄ Nanosheets for Microwave Absorption at 2–40 GHz

The development of microwave-absorbing materials (MAMs) with excellent performance is crucial for addressing electromagnetic (EM) interference issues. Two-dimensional (2D) Ti3C2Tx MXene has been considered to be a promising candidate for microwave absorption owing to its distinctive structure and performances. In this study, a “house of cards” heterostructure comprising multilayer Ti3C2Tx and vertically grown CoFe2O4 nanosheets (NSs) is fabricated by inducing an in situ vertical growth of positively charged CoFe-LDH NSs on Ti3C2Tx and a subsequent thermal treatment. The combination of Ti3C2Tx and CoFe2O4 NSs affords dielectric–magnetic synergistic effects on the overall EM properties of the heterostructure. On the one hand, vertically grown CoFe2O4 NSs on Ti3C2Tx shape the three-dimensional (3D) conductive network to consolidate conductive loss and generate numerous heterointerfaces to trigger intensive polarization loss. On the other hand, vertically grown CoFe2O4 NSs on Ti3C2Tx introduce additional loss mechanisms, such as magnetic loss and multiple reflection loss, thereby improving the impedance matching characteristic and reinforcing the loss capability of the composite. Most current studies on microwave absorption have focused on the frequency range of 2–18 GHz only, while we have extended this range to 40 GHz to explore the potential of the composite working in the higher frequency bands. The obtained optimal composite delivers satisfactory microwave absorption performance, including a minimum reflection loss (RLmin) value of −49.4 dB and a maximum effective absorption bandwidth (EABmax) value of 10.8 GHz. It is believed that this study will pave the way for the design of Ti3C2Tx-based MAMs and deepen the cognition of dielectric–magnetic synergistic mechanisms in the frequency range of 18–40 GHz

Synthesis of Highly Branched Polyethylene Using “Sandwich” (8‑<i>p</i>‑Tolyl naphthyl α‑diimine)nickel(II) Catalysts

Nickel­(II) α-diimine dibromide complexes incorporating 8-<i>p</i>-tolylnaphthylimino groups have been prepared and used for ethylene polymerization by activation with modified methylalumoxane (MMAO). These catalysts possess increased axial bulk relative to standard diimine-nickel complexes, resulting in lower rates of chain transfer relative to chain propagation rates and thus higher polymer molecular weights and narrower PDIs. They yield the most highly branched PE produced by Ni catalysts seen to date. The easy synthesis of 8-aryl-1-naphthylamines provides ready access to a new class of α-diimine-based nickel catalysts in which the 8-substituent is ideally positioned to provide steric bulk at the axial sites

3,4-<i>seco</i>-lupane triterpene derivatives with cytotoxic activities from the leaves of <i>Eleutherococcus sessiliflorus</i>

A new 3,4-seco-lupane triterpene, named sessiligenin (1), along with four known 3,4-seco-lupane triterpene derivatives (chiisanogenin 2, chiisanoside 3, divaroside 4, and sessiliside-A1 5) were isolated from the ethanol extract of the leaves of Eleutherococcus sessiliflorus (Rupr. & Maxim.) S.Y. Hu by silica gel column chromatography, and their structures were determined by spectroscopic data. Furthermore, all these compounds were tested for their cytotoxicities against cancer cell lines HepG2, B16-F10, Lewis and YAC-1, as well as normal cell lines NCTC1469 and HL-7702, and significant cytotoxicities had been found for this new compound (sessiligenin 1) which exhibited much lower cytotoxicities against normal cell lines NCTC1469 and HL-7702. It was deduced that the reduce of glycosyl from the structures of these 3,4-seco-lupane triterpenoids enhanced the cytotoxicities. Furthermore, with the complete removal of glycosyl group and the 11-hydroxyl and 3-carboxyl formed by the opening of the lactone ring, the cytotoxicity increased significantly.</p

A new 3,4-seco-lupane triterpenene glycosyl ester from the leaves of <i>Eleutherococcus sessiliflorus</i>

A new minor 3,4-seco-lupane triterpenene glycosyl ester, named sessiloside-A1 (1), along with three known 3,4-seco-lupane triterpenenes were isolated from the which alcohol extract of the leaves of Eleutherococcus sessiliflorus (Rupr. & Maxim.) S.Y. Hu by silica gel column chromatography, and their structures were determined by spectroscopic methods (UV, IR, NMR and HRMS). Compound 1 was elucidated to be β-D-glucopyranosyl ester of chiisanogenin. At the same time, a new efficient two-step enzymatic hydrolysis method was established to transform chiisanoside (2) → divaroside (3) → 1.</p

Calcium Vanadate Micro/Nanostructures for Lithium-Ion Batteries

The ability to control the composition and structure of inorganic compounds by simple synthesis methods is essential to the design and development of electrode materials of lithium-ion batteries (LIBs). Here we report the controllable synthesis of calcium vanadate micro/nanostructures via a simple hydrothermal method. By easily adjusting the pH value of a reaction system, a Ca10V6O25 straw-bundle-like structure, Ca2V2O7 microplatelet, and CaV6O16·3H2O sponge-like macrostructure can be selectively synthesized. The regulation mechanism of different calcium vanadate micro/nanostructures was investigated. In addition, CaV6O16·3H2O and CaV6O16·3H2O/GO self-standing papers were obtained by pressing the sponge-like macrostructure and vacuum filtration, respectively. The electrochemical performances of the CaV6O16·3H2O and CaV6O16·3H2O/GO papers as the self-standing and binder-free anodes for LIBs were investigated for the first time. The as-obtained CaV6O16·3H2O/GO hybrid paper anode exhibits a high discharge capacity of 664.0 mA h g–1 after 250 cycles at 200 mA g–1 and good cycling stability, demonstrating its potential application as a self-standing anode for LIBs

Synthesis and <i>in vitro</i> anticancer properties of a novel neodymium(III) complex containing tungstogermanate and 5-fluorouracil

<p>A novel neodymium(III) complex containing tungstogermanate and 5-fluorouracil, K₁₁(C₄H₄FN₂O₂)₂Nd(GeW₁₁O₃₉)₂·15H₂O (FNdGeW), was synthesized and its structure was characterized by ¹H NMR, IR, XRD, and TG-DSC. The results indicated that FNdGeW had Keggin structure of hetereopolyanion and structure of 5-fluorouracil. The thermal analysis showed that FNdGeW decomposed at 255.3 °C. MTT tests were performed to study the anticancer activities against SGC-7901 and HepG2 cells. The results showed that FNdGeW and FGeW possessed higher anticancer activities than 5-fluorouracil. FNdGeW exhibited the highest anticancer activities against SGC-7901 cells (IC₅₀ = 0.79 μmol•L^-1) and HepG2 cells (IC₅₀ = 0.37 μmol•L^-1).</p

Comparison of Four Quantitative Techniques for Monitoring Microalgae Disruption by Low-Frequency Ultrasound and Acoustic Energy Efficiency

Ultrasound has been regarded as an environmental friendly technology to utilize microalgae biomass and control algal blooms. In this study, four quantitative techniques, including cell counting, optical density of algal suspension, pigments release, and protein release, were performed on three species of microalgae (<i>M. aeruginosa</i>, <i>C. pyrenoidosa</i>, and <i>C. reinhardtii</i>) to develop effective techniques for rapid monitoring of cell disruption and to optimize the acoustic energy efficiency. Results showed optical density of algal suspensions was not an optimal indicator to monitor cell disruption, although it is a common technique for determining cell concentration in microbial cultures. Instead, an accurate and reliable technique was to determine the release of intracellular pigments (absorbance peaks of supernatant) for indicating cell rupture. The protein released during sonication could also be a useful indicator if it is the component of interest. A fitted power functional model showed a strong relationship between cell disruption and energy consumption (<i>R</i>² > 0.87). This model could provide an effective approach to directly compare the energy efficiency of ultrasound in different systems or with varying microalgae species. This study provides valuable information for microalgae utilization and the treatment of algal blooms by ultrasound, so as to achieve energy conservation and environmental safety

Toward Enhanced Electrochemical Performance by Investigation of the Electrochemical Reconstruction Mechanism in Co₂V₂O₇ Hexagonal Nanosheets for Hybrid Supercapacitors

As for hybrid supercapacitors, it is important to enhance the long cycling performance and high specific capacitance. In this paper, cobalt vanadate (Co2V2O7) hexagonal nanosheets on nickel foam are manufactured by a facile hydrothermal method and then transformed into numerous smaller size interconnected hierarchical nanosheets without any shape change via electrochemical reconstruction. Benefiting from the favorable architecture of hierarchical nanosheets via electrochemical reconstruction, the Co2V2O7 hexagonal nanosheet electrode exhibits a remarkable long cycling performance with 272% specific capacitance retention after 100,000 cycles at a current density of 5 A g–1 and then displays an increasing specific capacitance of 1834 F g–1 (tested at 1 A g–1). Furthermore, an aqueous hybrid supercapacitor device based on the Co2V2O7 hexagonal nanosheet electrode exhibits a high energy density of 35.2 Wh kg–1 at a power density of 1.01 kW kg–1 and an excellent cyclic stability with 71.4% capacitance retention after 10,000 cycles at 5 A g–1. These results offer a practicable pathway for enhancing the electrochemical properties of other metal oxides through electrochemical reconstruction