Chiral carbon dots can be widely used in various fields such as chiral recognition, chiral catalysis and biomedicine because of their unique optical properties, low toxicity and good biocompatibility. In addition, chiral carbon dots with circularly polarized luminescence (CPL) can be synthesized, thus broadening the prospects of chiral carbon dots applications. Since the research on chiral carbon dots is still in its infancy, this paper reviews the chiral origin, formation mechanism, chiral evolution, synthesis and emerging applications of chiral carbon dots, with a special focus on chiral carbon dots with CPL activity. It is hoped that it will provide some reference to solve the current problems faced by chiral carbon dots. Finally, the opportunities and challenges of the current research on chiral carbon dots are described, and their future development trends have also been prospected.
[ASAP] Low-Background CRISPR/Cas12a Sensors for Versatile Live-Cell Biosensing
Analytical Chemistry
DOI: 10.1021/acs.analchem.3c03131
Brain cancer classification based on multistage ensemble generative adversarial network and convolutional neural network
Abstract
An advanced approach that capitalizes on the synergies between multimodal feature fusion and the dual-path network is presented in this manuscript. Our proposed methodology harnesses a combination of potent techniques, merging the benefits of nonlinear mapping and expansive perception. The foundation of our methodology lies in leveraging well-established pretrained models, namely EfficientNet-B7, ResNet-152, and a meticulously crafted custom convolutional neural network (CNN), to effectively extract salient features from the data. These models are combined in a two-stage ensemble approach. We employ maximum variance unfolding (MVU) to select the most relevant attributes from the extracted features. In this study, we propose a hybrid approach that integrates a generative adversarial network and Neural Autoregressive Distribution Estimation (NADE-K) with a CNN. The resulting two-stage ensemble hybrid CNN model achieves an accuracy of 99.63%. The implementation of the two-stage ensemble hybrid CNN with MVU demonstrates significant improvements in brain tumor classification.
[ASAP] Correction to “Chemical Synthesis of La0.75Sr0.25CrO3 Thin Films for p-Type Transparent Conducting Electrodes”
Chemistry of Materials
DOI: 10.1021/acs.chemmater.3c02381
Strong Metal ‐ Support Interactions in ZrO2 ‐ Supported IrOx Catalyst for Efficient Oxygen Evolution Reaction
The use of ZrO2 as a support material for IrOx-based catalysts in oxygen evolution reaction (OER) electrocatalysis was studied using ex-situ characterization and rotating disk electrode electrochemical testing of supported IrxZr(1-x)O2 on ZrO2 of varying sizes. The catalyst exhibited high OER mass (specific) activity (712 A.gIr-1) and intrinsic activity (4.8 mA.cmECSA-2) at 1.6 VRHE, attributed to IrxZr(1-x)O2 alloy formation, an interconnected network of IrxZr(1-x)O2 nanoparticles and the presence of Ir(III)/Ir(IV) species throughout the bulk. It also appears to be resistant to Ir dissolution; however, accumulation of O2 bubbles and minor phase transformation of Ir(III)/Ir(IV) species during OER cause deactivation. Temperature-programmed desorption indicated a possible link between the observed high activity and higher amounts of adsorbed H2O and desorbed O2 species.
[ASAP] Chemical Bonding Origin of Mechanically Induced Glass Formation in a Coordination Polymer
Chemistry of Materials
DOI: 10.1021/acs.chemmater.3c01724
Phosphine‐Catalyzed (3+2) Annulation of Morita–Baylis–Hillman Carbonates with Pyrazolinone‐Derived Ketimines: Synthesis of Spirodihydropyrrole/dihydropyrazolones
A phosphine-catalyzed (3+2) annulation of Morita–Baylis–Hillman carbonates with pyrazolinone-derived ketimines has been achieved to give various spirodihydropyrrole/dihydropyrazolones in moderate to high yields with good diastereoselectivities. The protocol proved to be efficient with diverse MBH carbonates and ketimines. Both scale-up reaction and further transformation of the product were successfully. In addition, up to 98% ee of chiral product was obtained with the use of chiral bifunctional phosphine.
Relevant Advances in the Synthesis and Applications of N‐Glycopyranosides
In this work describe the natural occurrence, synthesis, mechanism, and pharmacological applications of N-glycopyranosides.
Abstract
N-glycosides are produced when an aglycone is connected, for example, using a glycosylation reaction, to the sugar moiety via linkage of C−N bond at anomeric carbon. N-glycosides are obtained from different precursors, including glucals, 1-azido glycosides, glycosyl azide, glycosyl isothiocyanate, 2-deoxy-2-iodo-N-glycoside, glycosyl-1H-1,2,3-triazol, and 2-nitroglucal. The biological relevance of N-glycopyranosides has drowned attracted the attention of several researchers. The scope of this review covers the literature from 2010 to 2022. Recent advances focused on the natural occurrence, synthesis, mechanism, and pharmacological applications of N-glycopyranosides are discussed.
Kinetics of Electrocatalytic Oxidation of Gallic Acid by Activated Glassy Carbon Electrode in Acidic Medium
Pristine glassy carbon (GC) electrode was just activated by applying voltage +1.8 V vs Ag/AgCl (sat. KCl) reference electrode. Then, using cyclic voltammetry techniques, the prepared activated GC was used to analyse the oxidation of gallic acid in acidic medium, and the resulting data was compared with that of pristine GC.
Abstract
An electrochemically functionalized glassy carbon (GC) electrode was prepared to study Gallic acid (GA) oxidation reaction in an acidic medium. The functionalized GC electrode was found to enhanced GA oxidation reaction in acidic medium by lowering oxidation potential and increasing corresponding current in comparison to a pristine GC. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and x-ray photoelectron spectroscopy (XPS) methods were used to analyze functionalized GC surface. The development of electropositive C=O functional groups were assumed to enhance the catalytic process. The specific capacitance of the electrode was calculated to be 92.91 μF by analysing EIS. Kinetics of GA oxidation over activated GC was calculated from CVs data. By analysing concentration dependent CVs it was found that the electrode process followed mass transfer limited first order kinetics. The GA oxidation mechanism is potential-dependent. For potentials above 0.42 V, the oxidation reaction involves the transfer of 2e− and 2H+ via a concerted mechanism, while at potentials below 0.42 V, the mechanism is stepwise. The reaction‘s standard rate constant (k°) was evaluated as 2.08×10−4 cm s−1.
Ultrasound‐assisted efficient aerobic oxidative coupling of thiols to disulfides with DiMIM‐CH3SO4 as a recyclable ionic liquid catalyst in water: A green approach
1,3-dimethyl imidazolium methyl sulfate (DiMIM-CH3SO4) ionic liquid-catalyzed the aerobic oxidative coupling of thiols to disulfides in water under ultrasonic irradiation at room temperature.
Abstract
An ultrasound-assisted method with specific characteristics of green chemistry for aerobic oxidative coupling of thiols to disulfides is presented. In this method, a readily available ionic liquid catalyzed the aerobic oxidative coupling of thiols to disulfides in water as a green solvent under ultrasonic irradiation at room temperature. In this novel sonocatalysis/ionic liquid protocol, aromatic thiols having both electron-donating and electron-withdrawing substituents, alkyl thiols and cysteine, were cleanly converted to the corresponding disulfides in excellent yields. This methodology uses 1,3-dimethyl imidazolium methyl sulfate (DiMIM-CH3SO4) ionic liquid as a recyclable catalyst and aerobic oxygen as an oxidative agent. This protocol has the advantages of high yields, short reaction times, lower cost, environmentally friendly reaction media, easy isolation of products, convenient procedure and recoverability of catalyst.