Carbon Analogues Research Articles

4hJCHOCH Spin Coupling in a Lewisx Trisaccharide as Evidence of Inter-Residue C-H···O Hydrogen Bonding in Aqueous Solution.

Prior studies of the solution conformation of the Lewisx (Lex) trisaccharide, αFuc-(1→3)[βGal-(1→4)]-βGlcNAc, suggest that nonclassical inter-residue C-H···O hydrogen bonding in aqueous solution contributes to the stabilization of its 3D structure and affects its biological properties. Experimental evidence for this hydrogen bond in aqueous solution has been reported in the form of a 4hJCHOCH NMR spin-coupling constant between C5'Fuc and H1″Gal measured by 2D NMR methods in unlabeled samples. A methyl glycoside of Lex (MeβLex) was prepared containing selective 13C-labeling at C5'Fuc, and the H1″Gal signal was examined in high-field 1H NMR spectra for evidence of splitting or line-broadening caused by the 13C at C5'Fuc. High-resolution 1H NMR spectra obtained at high field and at different temperatures using different FID processing parameters showed no resolved splitting of the H1″Gal signal or evidence of line-broadening. Spectral simulation showed that this splitting and/or line-broadening would be observable if the reported J-value (∼1.1 Hz) is correct. DFT calculations on MeβLex and a carbon analog (O5″Gal replaced by a CH2 group) gave very small and nearly identical calculated 4hJC5',H1″ values, suggesting that the coupling is essentially zero. DFT calculations also showed that an alternate inter-residue 3hJH5',H1″ is small. Based on NMR analyses and DFT calculations, we found that 4hJC5',H1″ in MeβLex has an upper limit of ∼0.4 Hz and that the value could be lower, possibly zero, calling into question its value as experimental proof of persistent nonclassical hydrogen bonding in aqueous solutions of MeβLex and related structures.

Visible-Light-Mediated Activation of Remote C(sp3)-H Bonds by Carbon-Centered Biradical via Intramolecular 1,5- or 1,6-Hydrogen Atom Transfer.

In this study, we introduce a novel intramolecular hydrogen atom transfer (HAT) reaction that efficiently yields azetidine, oxetane, and indoline derivatives through a mechanism resembling the carbon analogue of the Norrish-Yang reaction. This process is facilitated by excited triplet-state carbon-centered biradicals, enabling the 1,5-HAT reaction by suppressing the critical 1,4-biradical intermediates from undergoing the Norrish Type II cleavage reaction, and pioneering unprecedented 1,6-HAT reactions initiated by excited triplet-state alkenes. We demonstrate the synthetic utility and compatibility of this method across various functional groups, validated through scope evaluation, large-scale synthesis, and derivatization. Our findings are supported by control experiments, deuterium labeling, kinetic studies, cyclic voltammetry, Stern-Volmer experiments, and density functional theory (DFT) calculations.

Visible‐Light‐Mediated Activation of Remote C(sp3)−H Bonds by Carbon‐Centered Biradical via Intramolecular 1,5‐ or 1,6‐Hydrogen Atom Transfer

AbstractIn this study, we introduce a novel intramolecular hydrogen atom transfer (HAT) reaction that efficiently yields azetidine, oxetane, and indoline derivatives through a mechanism resembling the carbon analogue of the Norrish‐Yang reaction. This process is facilitated by excited triplet‐state carbon‐centered biradicals, enabling the 1,5‐HAT reaction by suppressing the critical 1,4‐biradical intermediates from undergoing the Norrish Type II cleavage reaction, and pioneering unprecedented 1,6‐HAT reactions initiated by excited triplet‐state alkenes. We demonstrate the synthetic utility and compatibility of this method across various functional groups, validated through scope evaluation, large‐scale synthesis, and derivatization. Our findings are supported by control experiments, deuterium labeling, kinetic studies, cyclic voltammetry, Stern–Volmer experiments, and density functional theory (DFT) calculations.

Facile synthesis of copper carbonate analog with peroxidase-like activity for colorimetric detection of isoniazid

In this article, copper carbonate analog with good peroxidase-like activity was successfully synthesized for the first time via a simple co-precipitation of CuSO4▪5H2O and Na2CO3. The obtained copper carbonate analog exhibited excellent intrinsic peroxidase-like activity towards a classical peroxidase substrate of 3, 3′, 5, 5′ -tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) under an acidic environment. The study of the catalytic mechanism confirmed that the hydroxyl radical produced from the decomposition of H2O2 is the main reactive oxygen species responsible for the catalytic oxidation of TMB to oxTMB. Moreover, results from kinetic parameter analysis indicated that H2O2 was more easily and/or likely to attach to the copper carbonate analog than TMB. Subsequently, the effects of experimental conditions (buffer pH, temperature, and incubation time) on the catalytic activity of the copper carbonate analog were also optimized. Finally, a copper carbonate analog-based colorimetric sensor was developed to determine isoniazid. Under the optimal conditions, the linear range for isoniazid was as broad as 0–178.6 μM, and the detection limit was as low as 8.47 μM. The spiked recoveries of isoniazid in normal human serum has been observed in the range of 94.8%–105.5 %. This strategy focuses on the development of a green, cost-efficient peroxidase mimic with high activity, good biocompatibility, and a simple synthesis process.

Structure and photophysical properties of furoquinoline aza-helicenes: Fluorescence enhancement by protonation

In recent years, the introduction of one or more heteroaromatic rings into a polyaromatic backbone has attracted growing interest as it allows significant control over optical, electronic and supramolecular characteristics. Polyheteroaromatic compounds are potential optoelectronic conjugate materials due to their photo- and electrochemical properties. This work describes the structure and photophysical properties of the first representatives of azaoxahelicenes of the furoquinoline series, synthesized from readily available starting compounds. Using X-ray diffraction analysis and DFT calculations, it was established that furan-fused aza [5]helicenes, unlike their carbon analogues, do not undergo Mallory-type photocyclization due to an increase in the distance between the terminal carbon atoms, which determines their greater resistance to UV light. A study of the acidochromic properties of the obtained compounds showed that protonation with trifluoroacetic acid (TFA) leads to an increase in the fluorescence intensity of most fluorophores. The best fluorescence enhancement was obtained for a fluorophore containing a methoxy substituent in the peripheral phenyl moiety, with a 10-fold increase in quantum yield. The introduction of a furoquinoline residue into the helicene skeleton leads to an improvement in fluorescent properties, as well as the possibility of their modulation by acidic agents. In the future, the first representatives of azaoxahelicenes of the naphthofuroquinoline series will be used to design new materials for optoelectronics and study their performance properties.

Diphosphaenones: Beyond the Phosphorus Analogue of Enones

Phosphaenones, like their carbon analogue enones (C=C–C=O), are promising building blocks for synthetic chemistry and materials science. However, in contrast to the α- and β-phosphaenones, structurally and spectroscopically well-defined diphosphaenones...

Influence of Formation Temperature on Cycling Stability of Sodium-Ion Cells: A Case Study of Na3V2(PO4)2F3 | HC Cells

Sodium-ion batteries are cheaper and attractive alternatives to lithium-ion batteries, particularly for low energy applications.1 Moreover, the Na+ cation, with its larger ionic radius and lower charge density than Li+, exhibits a weaker interaction within the ionic framework of electrode materials, as well as in solution, resulting in the higher power-rate capability of sodium materials. Hence, sodium-ion batteries based on Na3V2(PO4)2F3 (NVPF) | hard carbon (HC) and Prussian blue analogs (PBA) I HC chemistries are primarily promoted for their high power applications (nearly 80% charging of the cell within 10min). Of particular interest is the NVPF|HC system, due to its high energy density (~120 Wh/kg achieved in 18650 cell level) and high structural stability of NVPF material for long cycling.Our studies, together with others published in recent years, show that the electrode-electrolyte interphase (EEI) formed in the Na-ion cell is not stable as it partly dissolves during rest or discharge periods, and re-forms when recharging the cell.2 This dissolution and reformation cycle can lead to poor cycling stability and an increase in EEI thickness. A thicker EEI results in a higher impedance, which decreases the performance of the cell at high charge/discharge rates. Thus, different strategies have been explored to modify the EEI properties and enhance its stability, mainly focused on the incorporation of SEI-forming additives like vinylene carbonate or fluoroethylene carbonate.3 These additives could eventually stabilize the interphase but with the cost of increasing the interfacial impedance, hence affecting the power rate capability of the Na-ion cells, as mentioned before. Thus, different strategies are needed that allow for the formation of a stable interphase displaying high ionic conductivity (less resistance).Here, we show that it is possible to achieve a stable, ionically conducting interphase modulating the temperature during formation cycles. First, we demonstrated that the nature and chemical composition of the interphase changes as a function of the temperature applied during the formation cycles. The temperature of the cell is expected to play a role in the dissolution or precipitation of different chemical components, which helps us to tune the formation protocol, producing a stable and conducting interphase with or without electrolyte additives. The cells subjected to the optimized formation protocol exhibit low impedance, high power rate capability and long cycling stability. The results presented in this study benefit in great measure the future commercialization of NVPF|HC cells, but also are expected to be of value for other sodium cells based on HC anodes, by providing a framework to optimize the EEI formation and characteristics. References Tarascon, J.-M. Na-ion versus Li-ion Batteries: Complementarity Rather than Competitiveness. Joule 4, 1616–1620 (2020).Ma, L. A., Mogensen, R., Naylor, A. J. & Younesi, R. Solid Electrolyte Interphase in Na-ion batteries. in Na-ion Batteries 243–264 (John Wiley & Sons, Ltd, 2021). doi:10.1002/9781119818069.ch6.Eshetu, G. G. et al. Electrolyte Additives for Room-Temperature, Sodium-Based, Rechargeable Batteries. Chem. – Asian J. 13, 2770–2780 (2018).

Theoretical investigation of the vibrational and electronic properties of tetraphenylammonium and its boron, aluminum, gallium, carbon, silicon, germane, phosphorus and arsenic analogues

Tetraphenyl ammonium (Ph4N+ ) has long been considered a phantom ion due to the difficulty in synthesizing aryl ammonium compounds. Following the successful synthesis of Ph4N+ last year (2022), the equilibrium geometries of Ph4X (X = B-, Al-, and Ga- of group 13; C, Si, and Ge of group 14; and P+ and As+ of group 15) have been optimized using the B3LYP/6-31G(d,p) method with no symmetry constraints. According to the optimized structural data, Ph4N+ is considered the most sterically hindered molecule in this series of compounds, which reflects the difficulty of its synthesis. The calculated total energies of the Ph4X compounds reveal that their energies decrease down the group, and the cationic forms (group 15) are less energetic than their neutral (group 14) and anionic (group 13) counterparts. The optimized geometrical parameters were used to compute the UV–vis, IR, 1H NMR, and 13C NMR spectra of the nine terephenyl compounds. The frontier molecular orbital energies were used to determine ionization potentials, electron affinity, and other global reactivity descriptors of the nine Ph4X compounds. An accurate assignment of vibrational bands was made using the potential energy distribution (PED) method. The B3LYP/6-31G(d,p) method yielded good agreement with available experimental data for the molecules. The low HOMO-LUMO gaps suggest potential nonlinear optical properties of these compounds.

Sila-CBD Derivatives as Inhibitors of Heme-Induced NLRP3 Inflammasome: Application in Hemolytic Diseases.

Synthesis and biological evaluation of silicon-incorporated phytocannabinoids with improved pharmacological properties toward inflammatory diseases are described. The synthesized sila-analogues 15a, 15b, and 15c displayed potent inhibition of pro-inflammatory cytokines, including IL-1β, TNF-α, and IL-6 at 10 μM. Further, the release of heme during the lysis of red blood cells in hemolytic diseases is one of the major reasons for inflammation associated with the pathophysiology of these diseases. Due to scanty literature related to inhibitors of heme-mediated induction of the NLRP3 inflammasome, we decided to test these compounds against it. Compounds 15a and 15c significantly inhibited the heme-mediated induction of the NLRP3 inflammasome at a concentration of 0.1 μM. Interestingly, the sila-CBD derivatives also showed higher metabolic stability in contrast to their carbon analogues. Anti-NLRP3 inflammasome activity of compounds 15a and 15c were further validated in vivo against heme-mediated peritoneal inflammation. The anti-inflammatory activity of these compounds could be useful in treating diseases such as sickle cell anemia and thalassemia involving the hemolysis-mediated activation of the NLRP3 inflammasome.

Unlocking High‐Performance Supercapacitor Behavior and Sustained Chemical Stability of 2D Metallic CrSe2 by Optimal Electrolyte Selection

AbstractSupercapacitors are energy storage devices with the ability to rapidly charge and discharge, making them a valuable complement to battery systems. To maximize their fast‐charging capabilities, identifying materials and methods to enhance their energy density is crucial. In this work, we carried out a comprehensive study of an emerging 2D dichalcogenide, CrSe2, as a supercapacitor material. We demonstrate that CrSe2 can be obtained at ambient temperature through deintercalation of a relevant KCrSe2 precursor using a 0.5 M solution of I2 in acetonitrile. Although CrSe2 decomposed in 1 M KOH, it was found to be chemically stable in common electrolytes such as H2SO4, Li2SO4, and Na2SO4. Despite low surface area CrSe2 reached a specific capacitance of 27 F g−1 in 1 M H2SO4 and, thus consistently outperformed high surface carbon black. Computational studies suggested that the metallic conductivity of CrSe2 was likely the primary factor contributing to the superior performance of this 2D chalcogenide over high surface carbon analogues.

Optimizing gas transport for C3H6/C3H8 size sieving separation via fine pore engineering of carbon microspheres

For the adsorptive separation of propylene/propane (C3H6/C3H8) with high similarities in physiochemical properties, size-exclusive effect is highly attractive that can realize the superior selectivity. Nevertheless, the required narrow pores would unavoidably resist mass transfer of C3H6 molecules. To minimize the hindered diffusion, we report a systematic pore-engineering study in a family of carbon microspheres with fine-tuning pore sizes by exceptional activation-free method. The manipulation of pores was realized by varied temperature during glucose hydrothermal synthesis with acid additive as catalysis. Among as-obtained carbon analogs, GC-190 with optimal pore size closing to the kinetic diameter of C3H8 (5.11 Å), exhibited outstanding C3H6/C3H8 size-sieving property as well as fast C3H6 kinetics plausibly. However, GC-230 with smaller pores closing to the size of C3H6 (4.68 Å) showed sluggish C3H6 diffusion despite retaining size-sieving effect. The C3H6 diffusion constant rate (D’) of 1.21 × 10−2 min−1 on GC-190 is about two orders of magnitude higher than GC-230 of 2.29 × 10−4 min−1. DFT simulation further supports the remarkably reduced diffusion energy barrier of C3H6 by sub-angstrom level increased pore size. This study may deepen the understanding of gas diffusion in confined narrow pores and provides a general design concept.

Analysis of the Decomposition of Sulfur-Based Electrolyte Additives in Spent LiNi0.6Co0.2Mn0.2O2||AG Cells

The development and optimization processes of the last decades in the context of lithium ion batteries (LIBs) have led to a variety of electrode chemistries, which enable application-specific targets such as high energy, high power, high safety or long lifetime. Most of these LIB systems rely on a liquid carbonate-based electrolyte, whose basic composition has changed scarcely during this period.1 In this respect, the usage of electrolyte additives is one of the most economical and effective ways to further improve the overall performance, while also impact the application-tailored characteristics of the battery cells at the elctrolyte level without changing the bulk properties.2 These improvements can range from overcharge protection to lowered flammability or interphase formation, among others. In particular, film-forming additives signifcantly influence the performance and life time of LIBs by preventing excessive decomposition of the electrolyte, which is in contact with the positive and negative electrodes, by the formation of a passivation layer. Investigating the electrochemical decomposition of the electrolyte components, especially electrolyte additives, is key to enable a better understanding of the composition from the electrode||electrolyte interface layer and the effects on LIB cell performance.3 Thus, aging mechanisms and parasitic reactions can be elucidated to improve and design new electrolyte additives.Herein, the irreversible decomposition of sulfur-containing electrolyte additives will be addressed. Sulfur-containing additives represent an attractive option for film-forming additives as these compounds endow lower energies in the lowest unoccupied molecular orbital (LUMO) compared to the organic carbonate analogs and therefore are more susceptible to electrochemical reduction.4 However, these class of electrolyte additives find only a limited use in state-of-the-art electrolyte mixtures due to the often reported or suspected carcinogenicity and toxicity towards the human body. Nevertheless, since sulfur-containing additives still play an important role in spent LIBs of recent decades, identification of these hazardous compounds and formed aging products, which should be also classified as potential dangers, is of great interest.1 This contribution focused on the identification of aging products emerging in electrolytes from LIB cells using sulfur-based electrolyte additives of different chemical classes such as sulfates, sulfites, sultones and sulfonates. Ion chromatography and gas chromatography hyphenated to high-resolution acurrate mass spectrometry (HRAM-MS) were used to obtain information on the formation of ionic and volatile compounds after electrochemical operation and to elucidate the corresponding structures. Thus, specific ionic and volatile aging marker molecules could be defined for target-analysis of the original electrolyte additive in LIB material, despite a potentially complete consumption during cycling. This allows improved reverse-engineering of LIB post-mortem analysis and risk assessment. Furthermore, mechanistic conclusions on the decomposition of the investigated electrolyte additives could be drawn, extending literature reports based on X-Ray methods with respect to species information and ultimately contribute to a better understanding of the interphase constitutions.[1] C. Peschel, S. van Wickeren, A. Bloch, C. Lechtenfeld, M. Winter, S. Nowak, Energy Technol. 2022, xxx.[2] S. S. Zhang, J. Power Sources 2006, 162, 1379–1394.[3] J. Henschel, J. M. Dressler, M. Winter, S. Nowak, Chem. Mater. 2019 31 (24), 9970-9976.[4] B. Tong, Z. Song, H. Wan, W. Feng, M. Armand, J. Liu, H. Zhang, Z. Zhou, InfoMat 2021, 3, 1364–1392.

Crystallization-assisted asymmetric assembly of polymer nanocrescents and fidelity carbon analogues: Experiment and simulation study

Crystallization-assisted asymmetric assembly of polymer nanocrescents and fidelity carbon analogues: Experiment and simulation study

In-situ fabricated copper-holmium co-doped cobalt ferrite nanocomposite with cross-linked graphene as novel electrode material for supercapacitor application

Recently, hybrid electrode materials based on cross-linked carbon analogues have gained significant consideration for their excellent cyclic stability and high specific capacities. This work presents the fabrication of copper and holmium co-doped cobalt ferrite with cross-linked graphene (denoted as CH-CoF/CLG) through one-step hydrothermal route, as novel electrode material for supercapacitor study. The electrochemical performance of CH-CoF/CLG along with its counterparts i.e., CoF, CH-CoF was evaluated through CV, GCD, and EIS analysis using three electrode system. The specific capacitance (Csp) of CoF, CH-CoF, and CH-CoF/CLG nanocomposite at a sweep rate of 5 mV/s is 458 F/g, 762 F/g, and 1258 F/g, respectively, within a potential range of 0.0 to 0.6 V. For CH-CoF/CLG, the calculated slope value (b = 0.84) using power law showed that the energy storage mechanism is based on both capacitive and diffusional processes. The GCD test showed that CH-CoF/CLG exhibited long discharge time (td = 615 s), as compared to CH-CoF (td = 409 s), and CoF (td = 264 s). Moreover, after the fabrication of CH-CoF with CLG, the value of equivalent series resistance (ESR) and charge transfer resistance (Rct) for CH-CoF/CLG were decreased to 0.74 Ω and 0.84 Ω, compared to CoF (1.18 Ω and 1.29 Ω) and CH-CoF (0.88 Ω and 1.0 Ω). When tested for cyclic stability, CH-CoF/CLG displayed insignificant loss in performance up to 3000 cyclic runs. The high supercapacitor performance of CH-CoF/CLG can be assigned to the combined effects arising from the co-doping of transition metal and rare earth metal ions (Cu+2 and Ho+3) into CoF lattice, porous cross-linked structure, high wettability, low intrinsic resistance, and easy accessibility of KOH ions into deep layers of active material. As obtained results deduce that the CH-CoF/CLG nanocomposite is a competent capacitive material for energy storage.

Recent Advances in Selective C-H Bonds Functionalization through Aryl Radical- Mediated Hydrogen Atom Transfer Strategy

Abstract: Selective C-H bond functionalization of organic molecules has developed as an increasingly versatile platform that found wide applications in the synthesis of naturally occurring compounds, functional group modification, material sciences, and chemical and pharmaceutical industries. Apart from transition metal catalysis, which traditionally underwent a two-electron mechanism, a recent renascence of radical chemistry based on the hydrogen atom transfer (HAT) strategy has resulted in the rapid development of C-H bond functionalization. While many methodologies involving heteroatom-based HAT have been widely studied during the last decade, areas employing their carbon analogs were still challenging for chemists and remained less explored. Recent progress has been made to generate aryl radical species under relatively mild conditions, which can be utilized in the HAT step conveniently, and as a result, motivated the advancements of remote C(sp3)-H functionalization of various organic compounds, including amines, alcohols, amides and so on. This review will discuss the recent progresses in the functionalization of C-H bonds characterized by a key aryl HAT process, and, at the same time, some emphases have been laid on selective C-H functionalization catalyzed by photoredox chemistry.

Theoretical Study of Si/C Equally Mixed Dodecahedrane Analogues

To gain insight into the effect of Si/C arrangement on the molecular framework of strained polyhedral compounds, dodecahedrane analogues containing equal numbers of carbon and silicon (Si/C equally mixed dodecahedrane analogues) were investigated using the ab initio molecular orbital method. There are 1648 isomers for which the Si/C arrangement on the molecular framework is different. Based on the geometry optimization of all the isomers as well as the carbon and silicon analogues, the characteristics of the structure, relative energy, and strain energy of the Si/C equally mixed compounds are presented. Then, important factors controlling the relative energy, such as strain energy, are proposed through regression analysis. Also discussed is the correlation between the relative energy and the indices of Si/C dispersion, such as the number of skeletal C-Si single bonds and condensed five-membered rings constituting the polyhedral structure.

Mechanism of chlorotriflamidation of vinylsilanes with <i>N</i>,<i>N</i>-dichlorotriflamide

The mechanism of the reaction of vinylsilanes with N , N -dichlorotriflamide and the effect of a substituent at the silicon atom on the reaction course and on the charge distribution in substrates and their carbon analogues were studied by DFT method. The C=C bond in vinylsilanes and alkenes is polarized in the opposite way. The reaction proceeds in two stages: chlorination of the substrate with the formation of a chloronium ion, and its opening at the Cβ-Cl bond by the N -chlorotriflamide anion. Transition states of two stages were calculated. The reaction products are hydrolyzed to NH-derivatives; their IR spectra and supramolecular structure, including cyclic and linear dimers, calculated in the gas phase and in a polar medium, were studied.

BN Diamane-like Quasicrystal Based on 30° Twisted H-BN Bilayers and Its Approximants: Features of the Atomic Structure and Electronic Properties

The dodecagonal graphene quasicrystal (GQC) based on a 30° twisted bigraphene has been well investigated. Recently, the sp3-hybridizated carbon analog, the diamane quasicrystal as a H(F) functionalized GQC was proposed. Here we present a study of a similar sp3-hybridizated boron nitride 3-fold symmetry piezoelectric quasicrystal (BNnQC) based on a 30° twisted hexagonal BN bilayer (BNQC). The analysis of the atomic and electronic structures of its approximants based on 29.4° and 27.8° twisted h-BN bilayers has been carried by using of the density functional theory (DFT). The calculated values of the energy gaps ∼5 eV classify this predicted boron nitride material as a new wide-gap 2D quasicrystal.

Tunable Polymer Nanoreactors from RAFT Polymerization-Induced Self-Assembly: Fabrication of Nanostructured Carbon-Coated Anatase as Battery Anode Materials with Variable Morphology and Porosity.

We demonstrate a modular synthesis approach to yield mesoporous carbon-coated anatase (denoted as TiO2/C) nanostructures. Combining polymerization-induced self-assembly (PISA) and reversible addition-fragmentation chain-transfer (RAFT) dispersion polymerization enabled the fabrication of uniform core-shell polymeric nanoreactors with tunable morphologies. The nanoreactors comprised of a poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) shell and a poly(benzyl methacrylate) (PBzMA) core. We selected worm-like and vesicular morphologies to guide the nanostructuring of a TiO2 precursor, namely, titanium(IV) bis(ammonium lactato)dihydroxide (TALH). Subsequent carbonization yielded nanocrystalline anatase and simultaneously introduced a porous carbon framework, which also suppressed the crystal growth (∼5 nm crystallites). The as-prepared TiO2/C materials comprised of a porous structure, with large specific surface areas (>85 m2/g) and various carbon contents (20-30 wt %). As anode components in lithium-ion batteries, our TiO2/C nanomaterials improved the cycling stability, facilitated high overall capacities, and minimized the capacity loss compared to both their sans carbon and commercial anatase analogues.

BF3 Mediated [1,5]‐Hydride Shift Triggered Cyclization: Thioethers Join the Game

Abstract2‐(2‐(Benzylthio)benzylidene)malonates can undergo the 1,5‐hydride shift triggered cyclization resulting in thiachromanes in 45–84 % yield. Boron trifluoride as a reaction promotor is the key to success. DFT calculations revealed that the reaction proceeds via a chelate BF2 complex, which was confirmed by NMR‐analysis. Experimental and theoretical comparison of nitrogen, sulfur and carbon analogues revealed that sulfur derivatives have the highest activation barrier for the hydride transfer due to the unfavorable transition state geometry, which explains the lack of previous reports on 1,5‐hydride shifts in (alkylthio)styrenes.