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A new arylene ethynylene macrocycle (AEM) molecule bearing endo-acetamide groups was obtained by a Pd/Cu mediated homo-coupling reaction. Introducing tetraethylene glycol ether as a linkage between two C-shaped fragments substantially improved the final cyclization yield (30%). Concentration-dependent HNMR experiments indicated that strong aggregates formed through H-bonds were observed for this new macrocycle with amide groups in solution. And also, this macrocycle was fluorescent in solution and showed a highly selective fluorescence quenching response toward the highly toxic Hg. More importantly, this macrocycle could induce gelation of several solvents. Significantly, an interesting aggregation-induced enhanced emission (AIEE) behavior was observed for this macrocycle upon gelation. Both SEM and TEM investigations revealed that nanoporous structures existed in the xerogels. This study offers a new molecular design approach to develop fluorescent gels from planar AEM molecules with a functional cavity.
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http://dx.doi.org/10.1039/d0sm02144j | DOI Listing |
Nano Lett
August 2025
Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States.
We describe the design, synthesis, and single-molecule junction conductance of π-electron molecules bearing both radial and linear π-conjugation pathways, whereby cycloparaphenylene (CPP) radial cores are π-extended linearly with aryl alkyne substituents as models for previously reported CPP-arylene ethynylene conjugated polymers. Although radially and linearly conjugated molecules have been studied previously in isolation as junction-bridging molecular electronic units, this is the first study to examine molecules where both topologies are operative. Our results reveal that the presence of radial CPP components within the junction-spanning pathway leads to a reduction in the conductance of the backbone compared to model linear phenyl substituents.
View Article and Find Full Text PDFAcc Chem Res
August 2025
Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea.
ConspectusThe construction of synthetic counterparts that mimic the structures and functions of proteins and nucleic acids has become a central focus of research in supramolecular chemistry. Aromatic foldamers are capable of folding into secondary or higher-order structures that resemble those of biomacromolecules. Over the past two decades, a variety of aromatic foldamers have been developed, including -arylene ethynylene foldamers summarized in this Account.
View Article and Find Full Text PDFMolecules
November 2024
Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, USA.
J Am Chem Soc
February 2024
Kekulé-Institut für Organische Chemie und Biochemie der Universität Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany.
Phenanthracene nanotubes with arylene-ethynylene-butadiynylene rims and phenanthracene walls are synthesized in a modular bottom-up approach. One of the rims carries hexadecyloxy side chains, mediating the affinity to highly oriented pyrolytic graphite. Molecular dynamics simulations show that the nanotubes are much more flexible than their structural formulas suggest: In , the phenanthracene units act as hinges that flip the two macrocycles relative to each other to one of two possible sites, as quantum mechanical models suggest and scanning tunneling microscopy investigations prove.
View Article and Find Full Text PDFChemistry
September 2023
Chemistry Department, University of Wisconsin-Stevens Point, 2101 Fourth Avenue, Stevens Point, WI, 54481, USA.
Macrocycle formation that relies upon trans metal coordination of appropriately placed pyridine ligands within an arylene ethynylene construct provides rapid and reliable access to molecular rotators encapsulated within macrocyclic stators. Showing no significant close contacts to the central rotators, X-ray crystallography of Ag -coordinated macrocycles provides plausibility for unobstructed rotation or wobbling of rotators within the central cavity. Solid-state C NMR of Pd -coordinated macrocycles supports the notion of unobstructed movement of simple arenes in the crystal lattice.
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