Chemistry methods : new approaches to solving problems in chemistry最新文献

An apparatus for real-time in-situ monitoring of electrochemical advanced oxidation processes using visible spectrophotometry has been developed. Central to the design is a 3D-printed sleeve that interfaces commercially available electrochemical and spectrophotometry units. Using the anodic oxidation of Acid Orange 7 as a test bed, the apparatus has been used for probing the impact of varying electrode composition, current density, electrolyte concentration, and stirring speed on the rate of decolorization. In addition, the unit was used to prove that decolorization can continue after electrolysis has been stopped, thereby showing the inherent value of real-time monitoring. Given that a significant challenge in the field of advanced oxidation processes is the inability to compare different reported systems, our approach, using commercially available equipment and a printable interface may open avenues for more standardized data collection.

Plastic is an important commodity that is used in several sectors. However, plastic waste generation is a pressing issue and needs attention as it risks the environment. While methods such as landfilling, incineration and recycling are known for handling plastic waste, they have their own limitations like generation of secondary pollutants and the low quality of the recycled plastic. In this scenario, new methods and technologies for efficiently handling plastic waste are the need of the hour as it is aggravating the concern of pollution and its health risks. This highlight article predominantly focuses on the recently reported combinatorial approach (Angew. Chem. Int. Ed. 2022, 61, e202212013), where it has been shown that integrating the magnetic property of bare Fe₃O₄ nanoparticles and nanozyme technology can be used for microplastic removal and degradation with nearly 100 % efficiency.

Automated prediction of reaction impurities is useful in early-stage reaction development, synthesis planning and optimization. Existing reaction predictors are catered towards main product prediction, and are often black-box, making it difficult to troubleshoot erroneous outcomes. This work aims to present an automated, interpretable impurity prediction workflow based on data mining large chemical reaction databases. A 14-step workflow was implemented in Python and RDKit using Reaxys® data. Evaluation of potential chemical reactions between functional groups present in the same reaction environment in the user-supplied query species can be accurately performed by directly mining the Reaxys® database for similar or ‘analogue’ reactions involving these functional groups. Reaction templates can then be extracted from analogue reactions and applied to the relevant species in the original query to return impurities and transformations of interest. Three proof-of-concept case studies (paracetamol, agomelatine and lersivirine) were conducted, with the workflow correctly suggesting impurities within the top two outcomes. At all stages, suggested impurities can be traced back to the originating template and analogue reaction in the literature, allowing for closer inspection and user validation. Ultimately, this work could be useful as a benchmark for more sophisticated algorithms or models since it is interpretable, as opposed to purely black-box solutions.

Measuring molecular binding kinetics represents one of the most important tasks in molecular interaction analysis. Surface plasmon resonance (SPR) is a popular tool for analyzing molecular binding. Plasmonic scattering microscopy (PSM) is a newly developed SPR imaging technology, which detects the out-of-plane scattering of surface plasmons by analytes and has pushed the detection limit of label-free SPR imaging down to a single-protein level. In addition, PSM also allows SPR imaging with high spatiotemporal resolution, making it possible to analyze cellular response to the molecular bindings. In this Mini Review, we present PSM as a method of choice for chemical and biological imaging, introduce its theoretical mechanism, present its experimental schemes, summarize its exciting applications, and discuss its challenges as well as the promising future.

Driven by the transition to a CO₂-neutral energy economy, research on polymer electrolyte fuel cells gained much interest during the last decade, with researchers trying to overcome the sluggish kinetics of the oxygen reduction reaction (ORR) limiting their performance. Modification of existing ORR catalysts with small amounts of ionic liquids (IL) represents an innovative approach to altering the catalytic activity and stability. ILs are supposed to take effect by modifying the local microenvironment at electrochemical interfaces. Nevertheless, a thorough understanding about the local distribution of ILs over solid catalysts is still lacking, hindering the IL modification strategy to be a generic approach to rationally modulating the catalytic performance of a catalyst. In this study we employed STEM-EDS spectral imaging to locate the IL distribution on the catalyst in presence of Nafion^TM. To overcome the difficulties associated with low energy STEM-EDS we setup a sophisticated data processing routine based on machine learning.

Structural colors have been regarded as an ideal alternative to pigments because of the advantages of environmental friendliness, resistance to fading, especially in the fields of textile dyeing and printing, which is highly polluted in traditional ways and needs to be upgraded. They are generated by the interaction between the micro/nano structure of the material surface and the incident light, which is closely related to the sizes and periods of the structures. Based on different nano arrangements, the structures can be roughly divided into photonic crystals and non-photonic crystals. In this review, we summarized recent research progress in structural coloration of fibers and textiles. Learning from nature, researchers proposed various methods to fabricate biomimetic structural colors, and the applications of structural colored fibers and textiles were extended. The challenges and perspectives were also presented. Hopefully, reference for the design and preparation of structural color-based textiles can be inspired.

A major challenge in the development of molecular photoswitches capable of storing and releasing solar energy is to simultaneously realize many of the performance criteria required of the switches for such applications. Here, we take on this challenge by introducing an all-around performance descriptor that combines three key criteria (related to energy density, storage time and light-absorption characteristics), and by using density functional theory methods to calculate its values for 52 newly designed dihydroazulene/vinylheptafulvene (DHA/VHF) switches. Thereby, we are able to identify several switches with excellent overall properties that contain a structural motif absent in all DHA/VHF compounds previously considered for solar-energy storage. For some of these switches, we also provide retrosynthetic analyses and demonstrate that they form the energy-storing VHF isomer through a facile DHA→VHF photoisomerization reaction. All in all, we conclude that these switches show great promise for further development towards applications in solar-energy storage.

The identification of biotransformation products of drug compounds is a crucial step in drug development. Over the last decades, liquid chromatography-mass spectrometry (LC-MS) has become the method of choice for metabolite profiling because of its high sensitivity and selectivity. However, determining the full molecular structure of the detected metabolites, including the exact biotransformation site, remains challenging on the basis of MS alone. Here we explore infrared ion spectroscopy (IRIS) as a novel MS-based method for the elucidation of metabolic pathways in drug metabolism research. Using the drug midazolam as an example, we identify several biotransformation products directly from an in vitro drug incubation sample. We show that IR spectra of the aglycone MS/MS fragment ions of glucuronide metabolites establish a direct link between detected phase I and phase II metabolites. Moreover, using quantum-chemically computed IR spectra of candidate structures, we are able to assign the exact sites of biotransformation in absence of reference standards. Additionally, we demonstrate the utility of IRIS for structural elucidation by identifying several ring-opened midazolam derivatives formed in an acidic environment.