This paper describes the multicomponent dynamic covalent assembly of macrocyclic structures by utilizing hydrogen bonding-driven zigzag anthranilamides as "leading" components. Two or three amino groups have been introduced to one side of hydrogen bonded anthranilamide oligomers. The preorganization of the frameworks enabled the amino groups to condense with structurally matched aldehydes to form mono- and bimacrocycles in good to quantitative yields. Reactions from up to five components have been investigated, which involved one-step formation of up to six imine bonds. The preorganization of the templates highly enhanced the stability of the macrocyclic structures. As a result, all the macrocycles could be purified by simply recrystallizing the crude products from suitable solvents. Coexisting experiments of three series of three to five components were also performed, which all revealed that the preorganized precursors possessed high self-sorting capacity. On the basis of the same approach, a hydrazone-based macrocycle was also prepared quantitatively, while an intermacrocycle hydrazone-imine exchange was revealed to facilitate the formation of the hydrazone-based macrocycle from an imine-based macrocycle.
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Nanomaterials (Basel)
December 2024
Marine Engineering College, Dalian Maritime University, Dalian 116026, China.
Proton exchange membrane fuel cells (PEMFCs) are being pursued for applications in the maritime industry to meet stringent ship emissions regulations. Further basic research is needed to improve the performance of PEMFCs in marine environments. Assembly stress compresses the gas diffusion layer (GDL) beneath the ribs, significantly altering its pore structure and internal transport properties.
View Article and Find Full Text PDFThe length of actin filaments is regulated by the combined action of hundreds of actin-binding proteins. While the roles of individual proteins are well understood, how they combine to regulate actin dynamics in vivo remains unclear. Recent advances in microscopy have enabled precise, high-throughput measurements of filament lengths over time.
View Article and Find Full Text PDFNanoImpact
December 2024
European Commission, Joint Research Centre (JRC), Ispra, Italy.
In 2018 the European Commission adopted revisions to the Annexes of Regulation (EC) No 1907/2006 concerning registration, evaluation, authorisation and restriction of chemicals (REACH) to introduce nanomaterial-specific clarifications and provisions. Multicomponent nanomaterial (MCNM) is a non-regulatory term that has been used in recent EU-funded projects to describe nanomaterials with a complex structure and/or composition and which are expected to be increasingly used in products in the near future. This paper examines the regulatory preparedness of REACH, and its revised Annexes, for MCNMs.
View Article and Find Full Text PDFJ Phys Chem B
December 2024
Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States.
The achievement of sufficient dispersion of vulcanization accelerators is critical to tailoring superior cross-linked elastomers. Modern recipes rely on multicomponent formulations with silica particles covered by coupling agents. We study the molecular properties of select accelerators in polyisoprene melts and their affinity for functionalized surfaces via extensive all-atom molecular dynamics simulations.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Department of Mechanical Engineering, University of Washington, Seattle, WA, 98195, USA.
Vitrimer is a new, exciting class of sustainable polymers with healing abilities due to their dynamic covalent adaptive networks. However, a limited choice of constituent molecules restricts their property space and potential applications. To overcome this challenge, an innovative approach coupling molecular dynamics (MD) simulations and a novel graph variational autoencoder (VAE) model for inverse design of vitrimer chemistries with desired glass transition temperature (T) is presented.
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