Showing papers in "Collection of Czechoslovak Chemical Communications in 2022"

Aerobic Photocatalysis: Oxidation of Sulfides to Sulfoxides.

Abstract: Sulfoxides constitute one of the most important functional groups in organic chemistry found in numerous pharmaceuticals and natural products. Sulfoxides are usually obtained from the oxidation of the corresponding sulfides. Among various oxidants, oxygen or air are considered the greenest and most sustainable reagent. Photochemistry and photocatalysis is increasingly applied in new, as well as traditional, yet demanding, reaction, like the aerobic oxidation of sulfides to sulfoxides, since photocatalysis has provided the means to access them in mild and effective ways. In this review, we will summarize the photochemical protocols that have been developed for the oxidation of sulfides to sulfoxides, employing air or oxygen as the oxidant. The aim of this review is to present: i) a historical overview, ii) the key mechanistic studies and proposed mechanisms and iii) categorize the different catalytic systems in literature.

Late‐Stage Functionalization and Characterization of Drugs by High‐Throughput Desorption Electrospray Ionization Mass Spectrometry

Abstract: Late-stage functionalization (LSF) of drug molecules is an approach to generate modified molecules that retain functional groups present in the active drugs. Here, we report a study that seeks to characterize the potential value of high-throughput desorption electrospray ionization mass spectrometry (HT DESI-MS) for small-scale rapid LSF. In conventional route screening, HT-based DESI-MS provides contactless, rapid analysis, reliable and reproducible data, minimal sample requirement, and exceptional tolerance to high salt concentrations. Ezetimibe (E), an established hypertension drug, is targeted for modification by LSF. C-H alkenylation and azo-click reactions are utilized to explore this approach to synthesis and analytical characterization. The effect of choice of reactant, stoichiometry, catalyst, and solvent are studied for both reactions using high throughput DESI-MS experiments. Optimum conditions for the formation of LSF products are established with identification by tandem mass spectrometry (MS/MS).

Carbon Materials as Positive Electrodes in Bromine-Based Flow Batteries.

Abstract: Bromine based redox flow batteries (RFBs) can provide sustainable energy storage due to the abundance of bromine. Such devices pair Br2 /Br- at the positive electrode with complementary redox couples at the negative electrode. Due to the highly corrosive nature of bromine, electrode materials need to be corrosion resistant and durable. The positive electrode requires good electrochemical activity and reversibility for the Br2 /Br- couple. Carbon materials enjoy the advantages of low cost, excellent electrical conductivity, chemical resistance, wide operational potential ranges, modifiable surface properties, and high surface area. Here carbon based materials for bromine electrodes are reviewed, with a focus on application in zinc-bromine, hydrogen-bromine, and polysulphide-bromine RFB systems, aiming to provide an overview of carbon materials to be used for design and development of bromine electrodes with improved performance. Aspects deserving further R&D are highlighted.

Activation-Induced Surface Modulation of Biowaste-Derived Hierarchical Porous Carbon for Supercapacitors.

Abstract: Wheat straw-derived carbon from the Wheatbelt region in Western Australia was subjected to chemical activation in an electrolyte containing either acid or base treatment. The findings showed an increase in electron/hole mobility towards the interfaces due to the presence of different surface functional groups such as C-SOx -C and S=C in the carbon framework for acid activation. Likewise, the galvanostatic capacitance measured at a current density of 2 mA cm-2 in a three-electrode configuration for acid-activated wheat straw exhibited 162 F g-1 , while that for base-activated wheat straw exhibited 106 F g-1 . An increase of 34.5 % more capacitance was achieved for acid-treated wheat straw. This improvement is attributed to the synergistic effects between surface functional groups and electrolyte ions, as well as the electronic structure of the porous electrode.

Nanocellulose for Paper and Textile Coating: The Importance of Surface Chemistry.

Abstract: Nanocellulose has received enormous scientific interest for its abundance, easy manufacturing, biodegradability, and low cost. Cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) are ideal candidates to replace plastic coating in the textile and paper industry. Thanks to their capacity to form an interconnected network kept together by hydrogen bonds, nanocelluloses perform an unprecedented strengthening action towards cellulose- and other fiber-based materials. Furthermore, nanocellulose use implies greener application procedures, such as deposition from water. The surface chemistry of nanocellulose plays a pivotal role in influencing the performance of the coating: tailored surface functionalization can introduce several properties, such as gas or grease barrier, hydrophobicity, antibacterial and anti-UV behavior. This review summarizes recent achievements in the use of nanocellulose for paper and textile coating, evidencing critical aspects of coating performances related to deposition technique, nanocellulose morphology, and surface functionalization. Furthermore, beyond focusing on the aspects strictly related to large-scale coating applications for paper and textile industries, this review includes recent achievements in the use of nanocellulose coating for the safeguarding of Cultural Heritage, an extremely noble and interesting emerging application of nanocellulose, focusing on consolidation of historical paper and archaeological textile. Finally, nanocellulose use in electronic devices as an electrode modifier is highlighted.

Smart Drug Delivery Systems Based on DNA Nanotechnology.

Abstract: The development of DNA nanotechnology has attracted tremendous attention in biotechnological and biomedical fields involving biosensing, bioimaging and disease therapy. In particular, precise control over size and shape, easy modification, excellent programmability and inherent homology make the sophisticated DNA nanostructures vital for constructing intelligent drug carriers. Recent advances in the design of multifunctional DNA-based drug delivery systems (DDSs) have demonstrated the effectiveness and advantages of DNA nanostructures, showing the unique benefits and great potential in enhancing the delivery of pharmaceutical compounds and reducing systemic toxicity. This Review aims to overview the latest researches on DNA nanotechnology-enabled nanomedicine and give a perspective on their future opportunities.

Polyelectrolyte Multilayers in Capillary Electrophoresis.

Abstract: Capillary electrophoresis (CE) has been proven to be a performant analytical method to analyze both small and macro molecules. Indeed, it is capable of separating compounds of the same nature according to differences in their charge to size ratios, particularly proteins, monoclonal antibodies and peptides. However, one of the major obstacles to reach high separation efficiency remains the adsorption of solutes on the capillary wall. Among the different coating approaches used to control and minimize solute adsorption, polyelectrolyte multilayers can be applied to CE as a versatile approach. These coatings are made up of alternating layers of polycations and polyanions, and may be used in acidic, neutral or basic conditions depending on the solutes to be analyzed. This Review provides an overview of Successive Multiple Ionic-polymer Layer (SMIL) coatings used in CE, looking at how different parameters induce variations on the electro-osmotic flow (EOF), separation efficiency and coating stability, as well as their promising applications in the biopharmaceutical field.

Tailoring Single-Atom Platinum for Selective and Stable Catalysts in Propane Dehydrogenation.

Abstract: Propane dehydrogenation has been a promising method for producing propylene that has the potentials to meet the increasing global demand for propylene. However, owing to the restricted equilibrium conversion caused by the high endothermicity, even the Pt-based catalysts, which exhibit high activity and selectivity, severely suffer significantly from coke formation and/or nanoparticle sintering at realistic reaction temperatures, resulting in a short catalyst lifetime. As a result, few innovative catalysts in terms of catalytic activity, selectivity, and stability, have been produced. In this Review, we focus on the characteristics of single-atom-like Pt sites for PDH and attempt to provide suggestions for developing highly efficient catalysts. First, we briefly describe the fundamental strategies. Following that, the remarkable catalysis is addressed by three different distinct sorts of state-of-the-art single-atom-like Pt catalysts are discussed. Additionally, we present other promising catalyst design approaches that are not based on single-atom-like Pt catalysts, as well as future research challenges in this field.

Use of Limonene Epoxides and Derivatives as Promising Monomers for Biobased Polymers.

Abstract: (R)-Limonene, a renewable terpene, and its epoxidized derivatives, i. e. limonene epoxides, have prompted growing attention over the last decade as building blocks for the synthesis of biobased monomers and polymers. With the goal of replacing petroleum-based polymers several polymerization techniques have been applied on limonene oxide and limonene dioxide monomers. This paper aims to contribute to the literature by presenting a review dedicated to limonene oxide and dioxide as raw monomers of renewable origin for the development of biobased polymers. The polymerization techniques described are namely the homopolymerization, the copolymerization with carbon dioxide and anhydrides, and the copolymerization of limonene epoxide-based monomers. Limonene oxide polymerizations will be investigated first, followed by limonene dioxide polymerizations.

Soft Actuators Based On Carbon Nanomaterials.

Abstract: Inspired by the sophisticated design of biological systems, interest in soft intelligent actuators has increased significantly in recent years, providing attractive strategies for the design of elaborate soft mechanical systems. For the construction of those soft actuators, carbon nanomaterials were extensively and successfully explored for the properties of highly conductive, electrothermal, and photothermal conversion. This review aims to trace the recent achievements for the material and structural design as well as the general mechanisms of the soft actuators, paying particular attention to the contribution of carbon nanomaterials resulted from their diversified interplaying properties, which realized the flexible and dexterous deformation responding to various environmental stimuli, including light, electricity and humidity. The properties and mechanisms of soft actuators are summarized and the potential for future applications and research are presented.

Applications of Viologens in Organic and Inorganic Discoloration Materials.

Abstract: Viologen derived from 4,4'-bipyridine has attracted much attention because of its color changing properties with electron transfer, unique redox stability and structural diversity. These characteristics have led to its successful use in various applications, in particular in color-changing materials. In the past few years, researchers have been working on the syntheses of viologen-based color-changing functional materials, and such materials have been widely used in many fields. In photochromic materials, it is used as anti-counterfeiting material; in thermochromic, it is used as memory storage material, and in electrochromic, it is used as a battery material. This Review discusses the progress of viologen in organic and inorganic discoloration materials in recent years. The syntheses of viologen and its derivatives are summarized, and its application in the field of discoloration materials is introduced.

Oxetane Monomers Based On the Powerful Explosive LLM-116: Improved Performance, Insensitivity, and Thermostability.

Abstract: 3-Bromomethyl-3-hydroxymethyloxetane represents an inexpensive and versatile precursor for the synthesis of 3,3-disubstituted oxetane derivatives. In the present work, its synthesis was improved and energetic oxetanes based on the explosive LLM-116 (4-amino-3,5-dinitro-1H-pyrazole) prepared. Reaching detonation velocities and pressures of up to 7335 ms-1 and 20.9 GPa in combination with a high thermostability and insensitivity, these surpass the prior art by far. Next to a symmetric LLM-116 derivative, three asymmetric compounds were prepared using azido-, nitrato- and tetrazolyl-moieties. All compounds were intensively characterized by vibrational-, mass- and multinuclear (1 H, 13 C, 14 N) NMR spectroscopy, differential scanning calorimetry and elemental analysis. The molecular structures were elucidated by single crystal X-ray diffraction. Hirshfeld analysis allowed to estimate their sensitivity next to a practical evaluation using BAM standard procedures. Their performance was calculated using the EXPLO5 V6.04 code and a small-scale shock reactivity test and initiation test demonstrated their insensitivity and performance.

A 1,2-Dioxetane-Based Chemiluminescent Probe for Highly Selective and Sensitive Detection of Superoxide Anions in Vitro and in Vivo.

Abstract: Superoxide anion (O2 .- ), a short-lived, highly active reactive oxygen species, participates in many physiological processes. This work reports the design of a chemiluminescent probe (CLO) based on 1,2-dioxetane-phenol with a selective and sensitive response to O2 .- . The CLO consisted of a 1,2-dioxetane-phenol as a chemiluminophore core bearing a trifluoromethanesulfonate (Tf) moiety and methyl acrylate group. Upon reacting with O2 .- , the Tf was specifically cleaved from the CLO, resulting in chemiluminescence generation. The CLO emits chemiluminescence at 450-650 nm (λmax =540 nm), representing visible and red chemiluminescent molecules, responsive to O2 .- . The CLO processes high sensitivity (Limit of detection=66 nM) and selectivity for O2 .- with and has been applied to track O2 .- fluctuations in living cells and animals. In addition, CLO successfully detected and visualized O2 .- -related biochemical processes, making it promising as an important imaging tool for studying redox in biology and medicine.

Promising Electrocatalytic Water and Methanol Oxidation Reaction Activity by Nickel Doped Hematite/Surface Oxidized Carbon Nanotubes Composite Structures.

Abstract: Tailoring the precise construction of non-precious metals and carbon-based heterogeneous catalysts for electrochemical oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) is crucial for energy conversion applications. Herein, this work reports the composite of Ni doped Fe2 O3 (Ni-Fe2 O3 ) with mildly oxidized multi-walled CNT (O-CNT) as an outstanding Mott-Schottky catalyst for OER and MOR. O-CNT acts as a co-catalyst which effectively regulates the charge transfer in Ni-Fe2 O3 and thus enhances the electrocatalytic performance. Ni-Fe2 O3 /O-CNT exhibits a low onset potential of 260 mV and overpotential 310 mV @ 10 mA cm-2 for oxygen evolution. Being a Mott-Schottky catalyst, it achieves the higher flat band potential of -1.15 V with the carrier density of 0.173×1024 cm-3 . Further, in presence of 1 M CH3 OH, it delivers the MOR current density of 10 mA cm-2 at 1.46 V vs. RHE. The excellent electrocatalytic OER and MOR activity of Ni-Fe2 O3 /O-CNT could be attributed to the synergistic interaction between Ni-doped Fe2 O3 and O-CNT.

Singlet Oxygen Generation in Peripherally Modified Platinum and Palladium Porphyrins: Effect of Triplet Excited State Lifetimes and meso-Substituents on 1 O2 Quantum Yields.

Abstract: A series of meso-substituted with aromatic (=tolyl, pyrenyl, fluorenyl, naphthyl, and triphenylamine) substituents, platinum (Pt), and palladium (Pd) porphyrins have been synthesized and characterized by spectroscopic and single-crystal X-ray diffraction studies to probe structure-reactivity aspects on the electrochemical redox potentials, and phosphorescence quantum yields and lifetimes. In the X-ray structures, the aromatic meso-substituents were rotated to some extent from the planarity of the porphyrin ring to minimize steric hindrance. Both Pt and Pd porphyrins revealed higher electrochemical redox gaps as compared to their free-base porphyrin analogs as a result of the harder oxidation and reduction processes. The ability of both Pt and Pd porphyrins to generate singlet oxygen was probed by monitoring the photoluminescence of 1 O2 at 1270 nm. Higher quantum yields for both triplet sensitizers compared to their free-base analogs were witnessed. Singlet oxygen quantum yields close to unity were possible to achieve in the case of Pt and Pd porphyrins bearing triphenylamine substituents at the meso-position. The present study brings out the importance of different meso-substituents on the triplet porphyrin sensitizers in governing singlet oxygen quantum yields; a key property of photosensitizers needed for photodynamic therapy, chemical synthesis, and other pertinent applications.

Atomic Vacancies in Transition Metal Dichalcogenides: Properties, Fabrication, and Limits.

Abstract: Structural defects, such as heteroatoms or atomic vacancies, are always present in materials and significantly affect their physical properties, in both positive or unwanted ways. Interestingly, defects generate an impressive range of functionalities in many materials, such as catalysis, electrical and thermal conductivity tuning, thermoelectricity, enhanced ion storage, magnetism, and others. These properties enable the use of defective materials in a great variety of technological applications. Here we review the principal properties generated by atomic vacancies in 2D compounds and thin films of transition metal dichalcogenides and the most consolidated methods for their formation and engineering. Eventually, we critically analysed the most important advantages, the limits and the current open challenges.

Pd Reaction Intermediates in Suzuki-Miyaura Cross-Coupling Characterized by Mass Spectrometry.

Abstract: Palladium-catalyzed Suzuki-Miyaura (SM) coupling is widely utilized in the construction of carbon-carbon bonds. In this study, nanoelectrospray ionization mass spectrometry (nanoESI-MS) is applied to simultaneously monitor precatalysts, catalytic intermediates, reagents, and products of the SM cross-coupling reaction of 3-Br-5-Ph-pyridine and phenylboronic acid. A set of Pd cluster ions related to the monoligated Pd (0) active catalyst is detected, and its deconvoluted isotopic distribution reveals contributions from two neutral molecules. One is assigned to the generally accepted Pd(0) active catalyst, seen in MS as the protonated molecule, while the other is tentatively assigned to an oxidized catalyst which was found to increase as the reaction proceeds. Oxidative stress testing of a synthetic model catalyst 1,5-cyclooctadiene Pd XPhos (COD-Pd-XPhos) performed using FeCl3 supported this assignment. The formation and conversion of the oxidative addition intermediate during the catalytic cycle was monitored to provide information on the progress of the transmetalation step.

Structures and Spectra of Halide Hydrate Clusters in the Solid State: A Link between the Gas Phase and Solution State.

Abstract: This Review describes and assesses known solid-state examples of halide hydrates that are discrete in nature. Most of these are chloride hydrates, and most discrete clusters are dihalides, with very few mono- or multi-halide species found in the solid state. Polymeric chloride hydrates, on the other hand, are mostly 2D layered structures. We also observe that there is a gap in the chloride:water ratio between 8-20 waters per chloride. Isolated clusters can be found with 1-3 waters per chloride, 2D layers with 2-8 waters, and 3D semiclathrates with 20-38 waters. However, 1D chains comprise only 1-2 waters per chloride. [Cl(H2 O)]- is the only species found in both the solid state and gas phase and is also the only halide hydrate with a free OH group. Infrared spectra in the ν(OH) region are distinctive and useful for identification. Agreement between computed (gas phase) and experimentally-observed solid state structures and their vibrational spectra gives us confidence that discrete halide hydrate species observed in the solid state provide a useful link between gas phase species and structural motifs of halide hydrates in solution, especially microsolvated ion-pairs.

Rare Alkali Elements as Markers of Local Glass Working in Medieval Tolmo de Minateda (Spain)

Abstract: Abstract Analytical data of Roman and early Islamic glass established several primary glass production groups linked to glassmaking centres in the Levant and in Egypt. In contrast, the activities of secondary glass workshops are largely invisible in the compositional fingerprint of first millennium glass. Laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) of 261 glass finds from the Visigothic settlement of Tolmo de Minateda (Spain) revealed a site‐specific contamination pattern due to secondary glass processing and recycling, namely the enrichment of the glass batch by a unique combination of rare alkali elements (Li, K, Rb, Cs). With a median of 21 ppm, Li is particularly distinctive. Elevated lithium contents (Li>30 ppm) are also one of the characteristic features of Iberian plant ash glass from the Islamic period. The earliest known examples of this type of glass were found among the ninth‐century remains from Tolmo.

Structural Characterization of a New Collagen Biomimetic Octapeptide with Nanoscale Self‐Assembly Potential: Experimental and Theoretical Approaches

Abstract: Bioinspired peptides are attractive biomolecules which can improve our understanding of self-assembly processes for rational design of new peptide-based materials. Herein, a new amidated peptide FRSAPFIE (FRS), based on a sequence present in human collagen, was synthesized, characterized by mass spectrometry and subjected to self-assembling investigations. The optimal conditions for self-assembly were disclosed by dynamic light scattering at 32 °C and a peptide concentration of 0.51 %. In addition, AFM studies revealed ellipsoidal FRS shapes with an area between 0.8 and 3.1 μm2 . The ability of self-assembly was also proved using FAD dye as extrinsic fluorescence reporter. According to the theoretical analysis, the FRS peptide tends to form a bundle-type association, with a type of fibrillary tangles particle. Altogether, our findings address new challenges regarding the FRS peptide which can be used in further self-assembly studies to design biocompatible drug-delivery platforms.

Dynamic Transformation of DNA Nanostructures inside Living Cells.

Abstract: DNA nanostructures, that show sequence programmable responsiveness to intracellular signals, have been explored as potential candidates of artificial dynamic functional structures in living cells. Recently, we developed a series of intracellular signals responding DNA nanostructures in living cells to perform a special mission. In this review, the developed DNA nanostructures and their dynamic transformation properties are summarized and discussed. The DNA nanostructures are generally categorized into DNA-inorganic nanomaterials and DNA-organic nanomaterials depending on the composition. At the end of this review, the challenges and prospects on instructing dynamic DNA nanostructures in living cells are discussed. We believe that this review will contribute to the further development of stimuli-responsive nanomaterials, which is of great potential in biomedical applications.

Guanidine Carboxy Zinc Complexes for the Chemical Recycling of Renewable Polyesters.

Abstract: Our previously published non-toxic guanidine carboxy Zn catalysts, suitable for lactide ring opening polymerisation (ROP) under industrially preferred melt conditions, have been tested towards the alcoholysis of renewable polyesters. A structure-reactivity relationship has been found for the methanolysis of PLA in anhydrous THF, dependent on the substituents introduced at the ligand backbone. Using the unsubstituted "TMGasme" catalyst C2, a polyester conversion of 41 % was reached after 5 h at 60 °C. Introducing an electron density donating -NMe2 group at the ligand (C3) caused and increase in catalyst activity, resulting in a PLA conversion of 72 %. Hence, C3 was further tested, stressing the industrial applicability of PLA chemical recycling. Catalyst recycling, process scale up as well as solvent free alcoholysis, with full degradation in the PLA melt after 1 h, were demonstrated, allowing for the implementation of a circular (bio)plastics economy promoted by these catalysts.

Redox-Active Hydrocarbons: Isolation and Structural Determination of Cationic States toward Advanced Response Systems.

Abstract: Organic chemistry has developed rapidly as a carbon-based science. Particularly, hydrocarbons with aromatic rings have attracted much attention as molecular materials for use in organic electronics. In principle, aromatic species can be constructed if carbon and hydrogen atoms are available. Therefore, revealing the nature of pure hydrocarbons with an (anti)aromatic nature should pave the way for the development of as yet unexplored organic materials. In this Review, we focus on pure hydrocarbons composed of only carbon and hydrogen atoms, and present recent studies on their intrinsic electrochemical and spectroscopic properties and structural characterization of their cationic states. We also address more sophisticated hydrocarbon-based response systems that are capable of modulating their properties in response to external stimuli such as light, heat, and electric potential.

Strategies for the Construction of Functional Materials Utilizing Presynthesized Metal-Organic Cages (MOCs).

Abstract: Metal-organic cages (MOCs) that assemble from metal ions or metal clusters and organic ligands have attracted the interest of the scientific community because of their various functional coordination cavities. Unlike metal-organic frameworks (MOFs) with infinite frameworks, MOCs have discrete structures, making them soluble and stable in certain solvents and facilitating their application as starting reagents in the further construction of single components or composite materials. In recent years, increasing progress has been made in this field. In this review, we introduce these works from the perspective of design strategies, and focus on how presynthesized MOCs can be used to construct functional materials. Finally, we discuss the challenges and development prospects in this field.

Solid-State Characterization of Acetylpyridine Copper Complexes for the Activation of H2 O2 in Advanced Oxidation Processes.

Abstract: This work describes the synthesis of 4-(4-AcPy) and 3-acetylpyridine (3-AcPy) copper soluble complexes for the activation of hydrogen peroxide and the concomitant generation of reactive oxygen species (ROS). Given the paramagnetic effects of copper ions in the Nuclear Magnetic Resonance (NMR) lines, we aimed at demonstrating that the combination of high-resolution 2D solid-state NMR experiments, Electron Paramagnetic Resonance (EPR), single-crystal X-ray crystallography and Density Functional Theory (DFT) calculations allows a detailed study of the chemical structure of the ligands and the surrounding metal ions. The copper complexes synthesized with CuCl2 were useful for the activation of H2 O2 during which the only ROS was the hydroxyl one, as demonstrated by EPR experiments. A removal of methyl orange (MO) azo-dye higher than 85 % was achieved in 200 minutes, combining 1.7 mM of copper complexes with 60 mM of H2 O2 and 40 μM of MO.

Design, Synthesis, and Evaluation of Neomycin-Imidazole Conjugates for RNA Cleavage.

Abstract: Targeting RNA with synthetic small molecules attracted much interest during recent years as a particularly promising therapeutic approach in a large number of pathologies spanning from genetic disorders, cancers as well as bacterial and viral infections. In this work, we took advantage of a known RNA binder, neomycin, to prepare neomycin-imidazole conjugates mimicking the active site of ribonuclease enzymes able to induce a site-specific cleavage of HIV-1 TAR RNA in physiological conditions. These new conjugates were prepared using a straightforward synthetic methodology and were studied for their ability to bind the target, inhibit Tat/TAR interaction and induce selective cleavage using fluorescence-based assays and molecular docking. We found compounds with nanomolar affinity, promising cleavage activity and the ability to inhibit Tat/TAR interaction with submicromolar IC50 s.

Automated Bonding Analysis with Crystal Orbital Hamilton Populations.

Abstract: Understanding crystalline structures based on their chemical bonding is growing in importance. In this context, chemical bonding can be studied with the Crystal Orbital Hamilton Population (COHP), allowing for quantifying interatomic bond strength. Here we present a new set of tools to automate the calculation of COHP and analyze the results. We use the program packages VASP and LOBSTER, and the Python packages atomate and pymatgen. The analysis produced by our tools includes plots, a textual description, and key data in a machine-readable format. To illustrate those capabilities, we have selected simple test compounds (NaCl, GaN), the oxynitrides BaTaO2 N, CaTaO2 N, and SrTaO2 N, and the thermoelectric material Yb14 Mn1 Sb11 . We show correlations between bond strengths and stabilities in the oxynitrides and the influence of the Mn-Sb bonds on the magnetism in Yb14 Mn1 Sb11 . Our contribution enables high-throughput bonding analysis and will facilitate the use of bonding information for machine learning studies.

Peptide‐Conjugated Silver Nanoparticles for the Colorimetric Detection of the Oncoprotein Mdm2 in Human Serum

Abstract: Invited for this month's cover are the collaborating groups of Prof. Gilles Bruylants and Prof. Ivan Jabin, Université libre de Bruxelles, Belgium. The cover picture shows the principle of a colorimetric sensor, based on peptide-conjugated silver nanoparticles, for the detection of the cancer biomarker Mdm2. The particles were functionalized via a recently developed strategy based on the use of calixarene diazonium salts. The calixarene-based coating provides an unprecedented stability to the silver nanoparticles, enabling their use as colorimetric reporters for in vitro diagnostics. The cover was designed by I. Jabin. More information can be found in the Research Article by I. Jabin, G. Bruylants, and co-workers.

Aptamer-Functionalized Fractal Nanoplasmonics-Assisted Laser Desorption/Ionization Mass Spectrometry for Metabolite Detection.

Abstract: Accurate profiling of metabolites in biofluids provides a feasible approach to disease diagnosis and therapeutic evaluation in clinics. However, current material-based analytical platforms for in vitro metabolite detection often requires tedious sample pretreatment. To address this issue, herein, we report an aptamer-functionalized fractal gold nanoflower (Apt-AuNF)-based sensing platform for metabolite analysis. A series of fractal AuNFs with tunable nanoshell structures was synthesized using DNA-engineered strategy, and optimized Apt-AuNFs were demonstrated to enable efficient trap of target analytes with ∼5-fold enhanced enrichment, thus achieving selective analysis of metabolites in complex biofluids without requirement of pre-enrichment and purification. We applied Apt-AuNF-assisted laser desorption/ionization mass spectrometry for disease diagnosis, identifying diabetic patients through daily monitoring and glucose quantification in serum. This work provides a guideline to design materials for high-performance metabolic analysis and precise disease diagnosis.

Advances in Electrochemiluminescence Biosensors Based on DNA Walkers.

Abstract: Mediated by Watson-Crick base-pairing principle, DNA can be used to construct multi-functional molecular machines, such as DNA walkers, tweezers, logic gates and motors. It is noteworthy that DNA walkers with the advantages of programmability and diverse structures within the micro-nano scale have attracted intense attention in the field of biosensing, bioimaging, drug delivery, and genetic diagnosis. DNA walkers are comprised of driving power, walking strands and the tracks. The driving power acts as an external stimulus and the tracks as a platform for the walking strands to move autonomously. Under the specific external stimulus as driving power, such as strand displacement strategies, enzymatic reactions and environmental condition stimulus, DNA walkers could realize the generation and amplification of signals. Electrochemiluminescence (ECL) biosensors, combining ECL technology and bio-identification strategies, exhibit the virtue of high sensitivity, wide linear response range and low background interference. Recently, the construction of DNA walker-based ECL biosensors can amplify the targets and signals via multiple identification and recycles, achieving ultrasensitive detection for diverse targets. Herein, this review systematically summarizes the construction of different types of DNA walkers and their applications in ECL biosensors. Ultimately, this review summarizes and discusses the prospects for DNA walkers.