Electrophilic aromatic substitution in the calix[n]arene series is a well-established procedure leading exclusively to para-substituted derivatives. An unprecedented regioselectivity of the mercuration reaction leading to the meta-substituted calix[4]arenes is described. These compounds represent a new type of substitution pattern in classical calixarene chemistry and open the door for the straightforward synthesis of inherently chiral receptors based on calixarenes.
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http://dx.doi.org/10.1021/ol301420t | DOI Listing |
ACS Nano
January 2025
School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen (CUHK-Shenzhen), Guangdong 518172, P.R. China.
Helical structures such as right-handed double helix for DNA and left-handed α-helix for proteins in biological systems are inherently chiral. Importantly, chirality at the nanoscopic level plays a vital role in their macroscopic chiral functionalities. In order to mimic the structures and functions of natural chiral nanoarchitectures, a variety of chiral nanostructures obtained from artificial helical polymers are prepared, which can be directly observed by atomic force microscopy (AFM), scanning tunneling microscopy (STM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM).
View Article and Find Full Text PDFChaos
January 2025
School of Mechanical and Power Engineering, Zhengzhou University, Science Road 100, 450001 Zhengzhou, China.
In this paper, the complex and dynamically rich distribution of stable phases in the well-known discrete Ikeda map is studied in detail. The unfolding patterns of these stable phases are described through three complementary stability diagrams: the Lyapunov stability diagram, the isoperiod stability diagram, and the isospike stability diagram. The adding-doubling complexification cascade and fascinating non-quantum chiral pairs are discovered, marking the first report of such structures in discrete mapping.
View Article and Find Full Text PDFNat Commun
January 2025
College of Chemistry, Central China Normal University (CCNU), Wuhan, Hubei, PR China.
C-C and C-X bond forming reactions are essential tools in organic synthesis, constantly revolutionizing human life. Among the key methods for constructing new chemical bonds are nucleophilic addition reactions involving imines. However, the inherent challenges in synthesizing and storing imines have stimulated interest in designing stable precursors, which generates imines in situ during the reaction.
View Article and Find Full Text PDFACS Biomater Sci Eng
December 2024
Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana46556, United States.
Small extracellular vesicles (sEVs) are promising nanocarriers for drug delivery to treat a wide range of diseases due to their natural origin and innate homing properties. However, suboptimal therapeutic effects, attributed to ineffective targeting, limited lysosomal escape, and insufficient delivery, remain challenges in effectively delivering therapeutic cargo. Despite advances in sEV-based drug delivery systems, conventional approaches need improvement to address low drug-loading efficiency and to develop surface functionalization techniques for precise targeting of cells of interest, all while preserving the membrane integrity of sEVs.
View Article and Find Full Text PDFResearch (Wash D C)
December 2024
School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
Chirality has garnered significant attention in the scientific community since its discovery by Louis Pasteur over a century ago. It has been showing a profound impact on chemical, biomedical, and materials sciences. Significant progress has been made in controlling molecular chirality, as evidenced by the several Nobel Prizes in chemistry awarded in this area, particularly for advancements in the asymmetric catalytic synthesis of molecules with central and axial chirality.
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