Planar chiral [2.2]paracyclophane was employed as chiral scaffolds to twist an anthracene ring by tethering at its 1- and 8-positions; thus, twist chirality was induced in the anthracene moiety. The chiroptical properties of the resulting molecule, including circular dichroism (CD) and circularly polarized luminescence (CPL), were found to be derived from the twist chirality. An analogous molecule bearing long alkyl chains was a viscous liquid at ambient temperature, and its liquid film exhibited good CD and CPL profiles. Theoretical studies are carried out to determine the origin of these properties in the ground and excited states, which reproduced well the experimental results.
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http://dx.doi.org/10.1002/asia.202200418 | DOI Listing |
ACS Appl Mater Interfaces
December 2024
Beijing Institute of Smart Energy, Beijing 102200, China.
Supramolecular chirality has gained immense attention for great potential, in which the rational engineering strategy facilitates unique helical stacking/assembly, high chiroptical behavior, and prime biomedical activity. In this study, we reported a novel chiral organic donor-acceptor cocrystal based on asymmetrical components of benzo()naphtho(1,2-)thiophene (BNT) and 9-oxo-9H-indeno(1,2-)pyrazine-2,3-dicarbonitrile (DCAF) that exhibited red emission using a simple solution approach. During the self-assembly, a kinetically controlled growth of polar solvent or substrate induction led to the chiral packing and helical morphology twisted by the cooperation of electrostatic potential energy and chirality.
View Article and Find Full Text PDFScience
December 2024
Center for Complex Particle Systems (COMPASS), University of Michigan, Ann Arbor, MI, USA.
Planck's law ignores but does not prohibit black-body radiation (BBR) from being circularly polarized. BBR from nanostructured filaments with twisted geometry from nanocarbon or metal has strong ellipticity from 500 to 3000 nanometers. The submicrometer-scale chirality of these filaments satisfies the dimensionality requirements imposed by fluctuation-dissipation theorem and requires symmetry breaking in absorptivity and emissivity according to Kirchhoff's law.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
Ferroelectric nematic liquid crystals are polar fluids characterized by microscopic orientational ordering and macroscopic spontaneous polarizations. Within these fluids, domain walls that separate regions of different polarizations are ubiquitous. We demonstrate that the π walls in films of the polar fluids consist of twin half-integer surface disclinations spaced horizontally, enclosing a subdomain where the polarization exhibits left- or right-handed π twists across the film.
View Article and Find Full Text PDFChemistry
December 2024
Hiroshima University, Chemistry, 1-3-1 Kagamiyama, 739-8526, Higashi-Hiroshima, JAPAN.
The intermolecular host-guest complexation of head-to-tail monomers consisting of cleft-shaped bisporphyrin and trinitrofluorenone units connected by a chiral binaphthyl linker was employed to construct helically twisted supramolecular polymers. Results from 1H NMR, diffusion-ordered NMR spectroscopy, and viscometry experiments revealed that the supramolecular polymerization of these monomers follows a ring-chain competition mechanism. The introduction of bulky substituents at the linker significantly suppressed the formation of macrocyclic oligomers, whereas smaller alkyl chains facilitated the formation of the cyclic form.
View Article and Find Full Text PDFRep Prog Phys
December 2024
Department of Physics, The University of Hong Kong, The University of Hong Kong, Pokfulam, Hong Kong, Hong Kong, 999077, HONG KONG.
Spinless systems exhibit unique topological characteristics compared to spinful ones, stemming from their distinct algebra. Without chiral interactions typically linked to spin, an intriguing yet unexplored interplay between topological and structural chirality may be anticipated. Here we discover spinless topological chiralities solely from structural chiralities that lie in the 3D spatial patterning of structureless units, exemplified using two types of twisted graphite systems.
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