Recently, self-healing polymers based on disulfide compounds have gained attention due to the versatile chemistry of disulfide bonds and easy implementation into polymeric materials. However, the underlying mechanisms of disulfide exchange which induce the self-healing effect in poly(disulfide)s remain unclear. In this work, we elucidate the process of disulfide exchange using a variety of spectroscopic techniques. Comparing a model exchange reaction of 4-aminophenyl disulfide and diphenyl disulfide with modified reactions in the presence of additional radical traps or radical sources confirmed that the exchange reaction between disulfide compounds occurred via a radical-mediated mechanism. Furthermore, when investigating the effect of catalysts on the model exchange reaction, it could be concluded that catalysts enhance the disulfide exchange reaction through the formation of S-based anions in addition to the radical-mediated mechanism.
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http://dx.doi.org/10.1039/c6cp04028d | DOI Listing |
ACS Appl Mater Interfaces
January 2025
School of Integrated Circuits, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
Designing efficient and cost-effective electrocatalysts toward oxygen reduction reaction (ORR) under demanding acidic environments plays a critical role in advancing proton exchange membrane fuel cells (PEMFCs). Metal-nitrogen-carbon (M-N-C) catalysts with atomically dispersed metals have gained attention for their affordability, excellent catalytic performance, and distinctive features including consistent active sites and high atomic utilization. Over the past decade, significant achievements have been made in this field.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Chinese Academy of Sciences Qingdao Industrial Energy Storage Technology Institute, Department of Energy Science and Energy Technology, Songling Road, 189, 266101, Qingdao City, CHINA.
Membrane-assisted direct seawater splitting (DSS) technologies are actively studied as a promising route to produce green hydrogen (H2), whereas the indispensable use of supporting electrolytes that help to extract water and provide electrochemically-accelerated reaction media results in a severe energy penalty, consuming up to 12.5% of energy input when using a typical KOH electrolyte. We bypass this issue by designing a zero-gap electrolyzer configuration based on the integration of cation exchange membrane and bipolar membrane assemblies, which protects stable DSS operation against the precipitates and corrosion in the absence of additional supporting electrolytes.
View Article and Find Full Text PDFWorld J Surg Oncol
January 2025
Department of Oncology, The Second Xiangya Hospital of Central South University, Changsha, China.
Objective: This study aims to elucidate the therapeutic efficacy and safety of a taxane-based chemotherapy in combination with immune checkpoint inhibitors regimen in patients diagnosed with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC).
Methods: We retrospectively collected clinical data from 154 patients who received at least two cycles of PD-1 inhibitors in combination with a taxane-based chemotherapy as first-line treatment in seven hospitals in Hunan Province, between December 2018 and December 2023. These patients were subjected to long-term follow-up.
FEBS J
January 2025
Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland.
Rhizobium etli is a nitrogen-fixing bacterium that encodes two l-asparaginases. The structure of the inducible R. etli asparaginase ReAV has been recently determined to reveal a protein with no similarity to known enzymes with l-asparaginase activity, but showing a curious resemblance to glutaminases and β-lactamases.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Texas A&M University, Chemistry, UNITED STATES OF AMERICA.
The functionalization of pyridines at positions remote to the N-atom remains an outstanding problem in organic synthesis. The inherent challenges associated with overriding the influence of the embedded N-atom within pyridines was overcome using n-butylsodium, which provided an avenue to deprotonate and functionalize the C4-position over traditionally observed addition products that are formed with organolithium bases. In this work, we show that freshly generated 4-sodiopyrdines could undergo transition metal free alkylation reactions directly with a variety of primary alkyl halides bearing diverse functional groups.
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