Cross‐Coupling of Organolithium with Ethers or Aryl Ammonium Salts by C−O or C−N Bond Cleavage

Various aryl‐, alkenyl‐, and/or alkyllithium species reacted smoothly with aryl and/or benzyl ethers with cleavage of the inert C?O bond to afford cross‐coupled products, catalyzed by commercially available [Ni(cod)₂] (cod=1,5‐cyclooctadiene) catalysts with N‐heterocyclic carbene (NHC) ligands. Furthermore, the coupling reaction between the aryllithium compounds and aryl ammonium salts proceeded under mild conditions with C?N bond cleavage in the presence of a [Pd(PPh₃)₂Cl₂] catalyst. These methods enable selective sequential functionalizations of arenes having both C?N and C?O bonds in one pot.     

Preparation of BiVO4/MIL‐125(Ti) composite with enhanced visible‐light photocatalytic activity for dye degradation

Because of their desired features, including very specific surface areas and designable framework architecture together with their possibility to be functionalized, Metal Framework (MOF) is a promising platform for supporting varied materials in respect of catalytic applications in water treatment. In this work, a novel visible‐light‐responsive photocatalyst that comprised BiVO₄ together with MIL‐125(Ti), was synthesized by a two‐step hydrothermal approach. The characterization of as‐obtained samples as performed by X‐ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, Fourier transform infrared spectroscope, X‐ray photoelectron spectroscopy and ultraviolet‐visible diffuse reflection spectra. Rhodamine B was selected being a target for the evaluation of the photocatalytic function of as‐developed photocatalyst. The photocatalytic reaction parameters, for example, the content of BiVO₄ as well as initial concentration of Rhodamine B was researched. The composite photocatalyst possessing Bi:Ti molar ratio of 3:2 brought to light the fact that the greatest photocatalytic activity had the ability to degrade 92% of Rhodamine B in 180 min. In addition to that, the BiVO₄/MIL‐125(Ti) composite could keep its photocatalytic activity during the recycling test. The phenomenon of disintegration of the photo‐generated charges in the BiVO₄/MIL‐125(Ti) composite was brought to discussion as well.     

Investigating the Photostability of Quantum Dots at the Single‐Molecule Level

Quantum dots (QDs) have shown great potential to provide spatial, temporal, and structural information for biological systems. However, blinking, photobleaching, and spectral blueshift are adverse effects on their practical applications in biomedical research. An investigation of the effects of six reducing agents including cysteine (Cys), 1,4‐dithiothreitol (DTT), ethyl gallate (EG), L ‐glutathione (GSH), mercaptoacetic acid (MAA), and thiourea (TU) on the photostability of single QDs was studied. Our experiments demonstrate that both DTT and EG effectively inhibit blinking, photobleaching, and spectral blueshift. GSH molecules block blinking and photobleaching of QDs. The other reagents, Cys, MAA, and TU, only have the ability to counteract blinking. Possible explanations are given on the basis of research evidence. The results suggest possibilities for significant improvements in QDs for biological applications by adjusting the environmental conditions.     

Structure and dynamics of self-organized neuronal network with an improved STDP rule

Nonlinear Dynamics - The chemical synapses in a neural network are known to be modulated by the neuronal firing activities through the spike-timing-dependent plasticity (STDP) rule. In this paper,...     

Suppression of the Charge Density Wave State in Two-Dimensional 1T-TiSe2 by Atmospheric Oxidation

Two-dimensional (2D) metallic transition-metal dichalcogenides (TMDCs), such as 1T-TiSe₂, have recently emerged as unique platforms for exploring their exciting properties of superconductivity and the charge density wave (CDW). 2D 1T-TiSe₂ undergoes rapid oxidation under ambient conditions, significantly affecting its CDW phase-transition behavior. We comprehensively investigate the oxidation process of 2D TiSe₂ by tracking the evolution of the chemical composition and atomic structure with various microscopic and spectroscopic techniques and reveal its unique selenium-assisting oxidation mechanism. Our findings facilitate a better understanding of the chemistry of ultrathin TMDCs crystals, introduce an effective method to passivate their surfaces with capping layers, and thus open a way to further explore the functionality of these materials toward devices.     

Why to synthesize vaterite polymorph of calcium carbonate on the cellulose matrix via sonochemistry process?

Vaterite is an important biomedical material due to its features such as high specific surface area, high solubility, high dispersion, and small specific gravity. The purposes of this article were to explore the growth mechanism of vaterite on the cellulose matrix via sonochmistry process. In the work reported herein, the influences of experimental parameters on the polymorph of calcium carbonate were investigated in detail. The calcium carbonate crystals on the cellulose matrix were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Experimental results revealed that all the reactants, solvent, and synthesis method played an important role in the polymorph of calcium carbonate. The pure phase of vaterite polymorph was obtained using Na₂CO₃ as reactant in ethylene glycol on the cellulose matrix via sonochmistry process. Based on the experimental results, one can conclude that the synthesis of vaterite polymorph is a system process.