Chemistry-Methods

Single atom catalysts (SACs) harbor a potential to exceed nanoparticle catalysts in terms of activity, stability and selectivity in a growing number of chemical reactions. Although their investigation is attracting significant attention, important fundamental questions focusing on key physicochemical properties of SACs (e. g., structure – property relationships, structural dynamics, reaction‐driven restructuring) remain unanswered. A main challenge for research in the field is how to reliably characterize the environments of single atoms in the presence of complicating factors such as low weight loadings, strong metal‐support interactions, and atomic and multiscale heterogeneity of bonding in the single atom sites. This review addresses this challenge – identifying catalytically relevant features of physicochemical properties of single atoms (charge state, electronic structure, atomic configuration, bonding interactions with a support) and surveying advanced tools/methods for characterizing them. The review places a strong emphasis on multimodal methods exploiting X‐ray absorption, emission and photoelectron spectroscopies, and provides several examples from the authors’ research that demonstrate their use as powerful tools for SAC characterization.

Matthew Kottwitz

Yuanyuan Li

Haodong Wang

Anatoly I. Frenkel

Ralph G. Nuzzo

Chemistry–Methods

Chemistry Methods

Single Atom Catalysts: A Review of Characterization Methods

单原子催化剂：表征方法综述

Abstract Liquid Cell Transmission Electron Microscopy (LCTEM) is a great progression in nanostructure imaging, allowing the observation of chemical reactions in real time. It is widely reported, that this technique can be successfully used for analyzing nanoparticles synthesis, diffusion, aggregation and degradation. This gives a completely new insight into nanotechnological research. Normally, samples in TEM must be observed in vacuum, showing only the results of a performed experiment, whereas in situ observations in liquid environment provide information about the dynamics of the processes. LCTEM can show, how orientation of the particles/aggregates, surface roughness or solution flow rate influence the examined reaction. Those data are highly valuable for creating kinetic models of the reactions. There are however still some obstacles in LCTEM. Imaging of nanostructures in liquid environment is problematic since the electron beam reportedly may affect the observed sample. The beam modifies the temperature and pH of the liquid sample, changing the process dynamics. Therefore, its influence needs to be considered during in situ TEM observations. Nevertheless, LCTEM remains one of the highest achievements in the field of nanostructures imaging. In this review, recent achievements and developments of the LCTEM technique are presented.

Tomasz Tarnawski

Magdalena Parlińska‐Wojtan

Chemistry - Methods

Opportunities and Obstacles in LCTEM Nanoimaging – a review

LCTEM纳米成像中的机遇与挑战——综述

The Front Cover shows Wiener skewing in sedimentation velocity boundary of highly concentrated macromolecular solutions. The transient refractive index gradient produces an optical aberration that can be recognized by the displacement of the Rayleigh interference optical baseline features associated with the migrating refractive index gradient. The red lines represent two select baseline blips with best-fit translation and slope. Global analysis of the translation versus slope data reveals the magnitude of Wiener skewing, which then can be modeled in the sedimentation analysis. More information can be found in the Research Article by Sumit K. Chaturvedi and Peter Schuck (DOI: 10.1002/cmtd.202400035).

Sumit K. Chaturvedi

Peter Schuck

Cover Picture: Analysis of Macromolecular Size Distributions in Concentrated Solutions (Chem. Methods 12/2024)

封面图片：浓溶液中大分子尺寸分布的分析（《化学方法》2024年12月）

Abstract A 17 O solid‐state NMR method for salt/co‐crystal discrimination in binary compounds of carboxylic acids is presented. The method incorporates a quick and relatively inexpensive labelling protocol for mechanochemical 17 O enrichment of the carboxyl oxygen positions, as previously described by Metro et al. Angew. Chem. 2017, 56, 6803, followed by a visual interpretation of the recorded 17 O solid‐state magic‐angle spinning (MAS) NMR spectra in terms of the nature of the enriched oxygen sites in the prepared binary compound. Care must be taken where variable‐temperature changes in the 17 O MAS spectra are observed. Nevertheless, we observe that, at low temperatures, the averaging effect of chemical exchange of the carboxyl/carboxylate moieties can be avoided and two well separated 17 O lines are obtained for a carboxylic acid, whereas the almost equivalent carboxylate oxygen sites give rise to a single NMR signal. The method is illustrated in two cases, one in which salts can be identified also from their 1 H solid‐state NMR spectra by the absence of high ppm resonances due to hydrogen bonding, and another one, the more general case of organic crystals with multiple hydrogen bonding, where only 17 O solid‐state NMR spectra can be employed for salt/co‐crystal discrimination. A quantitative analysis of 17 O solid‐state NMR spectral parameters can provide useful information in structural studies by NMR crystallography approaches.

Ioana‐Georgeta Grosu

Dinu Iuga

Ben P. Tatman

Maria O. Miclaus

Steven P. Brown

Claudiu Filip

Salt/Co‐Crystal Discrimination Made Easy by <sup>17</sup>O Solid‐State NMR

通过<sup>17</sup>O固态核磁共振轻松区分盐/共晶

Abstract The open‐access movement in chemistry has led to a surge in publicly accessible data repositories such as PubChem and ChemSpider, housing more than 100 million chemical compounds. These repositories are invaluable for large‐scale virtual screening but lack crucial pricing information, a vital economic aspect influencing commercial decisions. Currently, these databases merely provide hyperlinks to vendor websites for pricing details, necessitating manual exploration due to the diverse structures of vendor websites, making automated data extraction impractical. To tackle this challenge, we introduce ChemPrice, a Python package that streamlines the collection of pricing data through the integration of ChemSpace, Mcule, and Molport platforms that provide up‐to‐date price information from over 100 suppliers. ChemPrice standardizes pricing units, offering consolidated and best‐pricing information for specified compounds. Its modular design facilitates integration into automated virtual screening workflows, and a user‐friendly web interface caters to those with limited coding skills, enabling easy compound list uploading and pricing data retrieval. This innovation addresses the complexity of collecting compound prices and enables integration into the virtual screening code workflows, providing a valuable resource for a wide community of users seeking comprehensive and up‐to‐date pricing information to enhance their decision‐making processes.

Murat Cihan Sorkun

Baptiste Saliou

Süleyman Er

ChemPrice, a Python Package for Automated Chemical Price Search

ChemPrice，一个用于自动化化学品价格搜索的Python包

Abstract We present the Multi‐site (MS) QuantEXAFS approach, designed to model the EXAFS data from samples containing an element in different local bonding geometries. Building upon our QuantEXAFS method, which maps experimental extended X‐ray absorption fine structures (EXAFS) data to DFT‐optimized structures, MS‐QuantEXAFS introduces the key capability to probe fractional contributions of multiple sites that may be present in an experimental sample. Specifically, we demonstrate effectiveness of this technique by investigating mixed samples containing known fractions of site‐isolated subsurface Pt/MgO with Pt nanoparticles uniformly supported on MgO. The ‘site‐fractions’ obtained through MS‐QuantEXAFS closely match (i. e., ±6%) the known fractions of the physically mixed samples. This approach has been generalized to other oxides, and thus represents an important advance in quantifying the speciation of non‐uniform catalyst samples.

Rachita Rana

Jiyun Hong

Adam S. Hoffman

Baraa Werghi

Simon R. Bare

Ambarish R. Kulkarni

Quantifying the Site Heterogeneities of Non‐Uniform Catalysts Using QuantEXAFS

使用QuantEXAFS量化非均匀催化剂的位点异质性

Abstract Renewable chemicals from carbohydrate‐rich wastes, like furfural and 5‐hydroxymethylfurfural (HMF), are gaining prominence as alternatives to petroleum‐based resources. Assessing the suitability of biomass as feedstock for furfural and HMF production requires knowledge of its composition. This study focuses on developing and validating predictive models for individual sugar concentrations in hydrolysates using quantitative 1H NMR data. Utilizing partial least square (PLS) regression, the dataset includes 137 NMR spectra of multi‐component sugar standards (arabinose, fructose, galactose, glucose, mannose, maltose, sucrose, and xylose). The best‐performing model achieved an R 2 of 0.987–0.999 and RMSECV of 0.37–1.56 mM and is based on the non‐overlapping area of the NMR spectrum. Real‐world samples were used for validation, resulting in predicted sugar concentrations with a mean standard deviation of 0.5 mM. This high accuracy and streamlined analysis process make these models practical for quantifying large sample sets, showcasing the reliability and accessibility of extracting statistical information from H‐NMR data.

Kristoffer Mega Herdlevær

Kasper Strandengen

Camilla Løhre

Tanja Barth

Determination of Sugar Concentrations in Aqueous Solution Using Multivariate Predictions Based on 1H‐NMR Spectroscopy

基于1H-NMR光谱的多变量预测法测定水溶液中糖浓度的研究

短名	Chemistry Methods
Journal Impact	5.95
国际分区	CHEMISTRY, MULTIDISCIPLINARY(Q1)

出版信息	出版商: John Wiley and Sons Inc，出版周期: ，期刊类型: journal，开源期刊: 否
基本数据	创刊年份: 2021，原创研究文献占比: ，自引率:， Gold OA占比:

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Single Atom Catalysts: A Review of Characterization Methods

Opportunities and Obstacles in LCTEM Nanoimaging – a review

Cover Picture: Analysis of Macromolecular Size Distributions in Concentrated Solutions (Chem. Methods 12/2024)

Salt/Co‐Crystal Discrimination Made Easy by ¹⁷O Solid‐State NMR

ChemPrice, a Python Package for Automated Chemical Price Search

Salt/Co‐Crystal Discrimination Made Easy by ¹⁷O Solid‐State NMR

Cover Picture: Analysis of Macromolecular Size Distributions in Concentrated Solutions (Chem. Methods 12/2024)

Quantifying the Site Heterogeneities of Non‐Uniform Catalysts Using QuantEXAFS

ChemPrice, a Python Package for Automated Chemical Price Search

Determination of Sugar Concentrations in Aqueous Solution Using Multivariate Predictions Based on 1H‐NMR Spectroscopy

Chemistry-Methods

期刊引文格式

有 1 位以上作者的期刊

有 2 位作者的期刊

有 3 位作者的期刊

有 5 位以上作者的期刊

书籍引用格式

学位论文引用格式

网页引用格式

专利引用格式

手工熬夜修改参考文献？研飞自动匹配期刊，一键轻松成稿，支持 Word/WPS

投稿经验分享

Single Atom Catalysts: A Review of Characterization Methods

Opportunities and Obstacles in LCTEM Nanoimaging – a review

Cover Picture: Analysis of Macromolecular Size Distributions in Concentrated Solutions (Chem. Methods 12/2024)

Salt/Co‐Crystal Discrimination Made Easy by 17O Solid‐State NMR

ChemPrice, a Python Package for Automated Chemical Price Search

Salt/Co‐Crystal Discrimination Made Easy by 17O Solid‐State NMR

Cover Picture: Analysis of Macromolecular Size Distributions in Concentrated Solutions (Chem. Methods 12/2024)

Quantifying the Site Heterogeneities of Non‐Uniform Catalysts Using QuantEXAFS

ChemPrice, a Python Package for Automated Chemical Price Search

Determination of Sugar Concentrations in Aqueous Solution Using Multivariate Predictions Based on 1H‐NMR Spectroscopy

Salt/Co‐Crystal Discrimination Made Easy by ¹⁷O Solid‐State NMR

Salt/Co‐Crystal Discrimination Made Easy by ¹⁷O Solid‐State NMR