The bottom-up assembly of chiral structures usually relies on a cascade of molecular recognition interactions. A thorough description of these complex stereochemical mechanisms requires the capability of imaging multilevel coordination in real-time. Here we report the first direct observation of hierarchical expression of supramolecular chirality at work, for 10,10'-dibromo-9,9'-bianthryl (DBBA) on Cu(111). Molecular recognition first steers the growth of chiral organometallic chains and then leads to the formation of enantiopure islands. The structure of the networks was determined by noncontact atomic force microscopy (nc-AFM), while high-speed scanning tunnelling microscopy (STM) revealed details of the assembly mechanisms at the ms time-scale. The direct observation of the chirality transfer pathways allowed us to evaluate the enantioselectivity of the interchain coupling.
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http://dx.doi.org/10.1039/c7cp01341h | DOI Listing |
Materials (Basel)
January 2025
College of Chemistry, Sichuan University, Chengdu 610064, China.
Circularly polarized luminescence (CPL) is an emerging field with significant applications in molecular electronics, optical materials, and chiroptical sensing. Achieving efficient CPL emission in organic systems remains a major challenge, particularly in the development of materials with high fluorescence quantum yields (Φ) and large luminescence dissymmetry factors (g). Herein, we report the efficient synthesis of shape-persistent tetraphenylethylene macrocycles and investigate its potential as a CPL material.
View Article and Find Full Text PDFACS Appl Bio Mater
January 2025
School of Chemistry, Pharmacy and Food Biosciences, University of Reading, Whiteknights, Reading RG6 6AD, U.K.
A series of tripodal (three-arm) lysine-based peptides were designed and synthesized and their self-assembly properties in aqueous solution and antimicrobial activity were investigated. We compare the behaviors of homochiral tripodal peptides (KKY)K and a homologue containing the bulky aromatic fluorenylmethoxycarbonyl (Fmoc) group Fmoc-(KKY)K, and heterochiral analogues containing k (d-Lys), (kkY)K and Fmoc-(kkY)K. The molecular conformation and self-assembly in aqueous solutions were probed using various spectroscopic techniques, along with small-angle X-ray scattering (SAXS) and cryogenic-transmission electron microscopy (cryo-TEM).
View Article and Find Full Text PDFActa Histochem
January 2025
School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK.
In recent years, a great interest has been focused on the prebiotic origin of nucleic acids and life on Earth. An attractive idea is that life was initially based on an autocatalytic and autoreplicative RNA (the RNA-world). RNA duplexes are right-handed helical chains with antiparallel orientation, but the rationale for these features is not yet known.
View Article and Find Full Text PDFRSC Chem Biol
December 2024
Department of Chemistry, Texas A&M University College Station Texas 77843 USA
Despite the growing interest in mirror-image l-oligonucleotides, both as a robust nucleic acid analogue and as an artificial genetic polymer, their broader adoption in biochemical research and medicine remains hindered by challenges associated with the synthesis of long sequences, especially for l-RNA. Herein, we present a novel strategy for assembling long l-RNAs the joining of two or more shorter fragments using cross-chiral ligase ribozymes together with new substrate activation chemistry. We show that 5'-monophosphorylated l-RNA, which is readily prepared by solid-phase synthesis, can be activated by chemical attachment of a 5'-adenosine monophosphate (AMP) or diphosphate (ADP), yielding 5'-adenosyl(di- or tri-)phosphate l-RNA.
View Article and Find Full Text PDFSmall
January 2025
Shanghai Key Laboratory of Advanced Polymeric Materials, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Endowing biomimetic sequence-controlled polymers with chiral functionality to construct stimuli-responsive chiral materials offers a promising approach for innovative chiroptical switch, but it remains challenging. Herein, it is reported that the self-assembly of sequence-defined chiral amphiphilic alternating azopeptoids to generate photo-responsive and ultrathin bilayer peptoidosomes with a vesicular thickness of ≈1.50 nm and a diameter of around ≈290 nm.
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