Twisted Nanographenes with Robust Conformational Stability

Nanomaterials, Journal Year: 2024, Volume and Issue: 14(21), P. 1737 - 1737

Published: Oct. 30, 2024

Owing to a lack of methodology for rationally and selectively synthesizing twisted nanographenes, it is usually inevitable that we obtain nanographenes as mixture with various geometries, such unidirectionally twisted, alternatively randomly even wavy structures, reflecting the high activation barriers among them. Otherwise, they are interconvertible if low enough only averaged properties can be observed under thermal equilibrium. Recently, reported on double-twisted nanographene containing four [6]helicene units within skeleton. In this paper, discuss robust conformational stability nanographene, both experimentally computationally. The results indicate could racemized at temperatures exceeding 200 °C, first flip one rate-degerming step.

Language: Английский

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Synthesis, Chiroptical Properties, and Absolute Configuration Determination of Phenyl‐4‐pyridyl‐2,5‐dipyrimidinylmethane

Asian Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 9, 2024

Abstract Phenyl‐4‐pyridyl‐2,5‐dipyrimidinylmethane ( 1 ) has been synthesized in five steps from 5‐methylpyrimidine. The structural feature of is the symmetry elements with respect to 180° rotation aryl group along central C−C bonds. Due this feature, compound expected good crystallinity despite asymmetric molecular structure. optical resolution was achieved by high performance liquid chromatography using chiral stationary phase (chiral HPLC). circular dichroism (CD) spectra two fractions showed opposite signs. As expected, X‐ray crystallographic analysis successfully performed for both racemic and enantiomerically pure crystals , nitrogen atoms being unambiguously assigned cases. It concluded first‐eluted fraction HPLC determined be S configuration CD calculation reproducing experimental spectrum anomalous diffraction .

Language: Английский

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Oxidation Triggered Supramolecular Chirality

Nano Letters, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 9, 2024

Topochemical reactions normally occurring in the solid and crystalline state exhibit solvent-free catalyst-free properties, with high atom economy which have been widely applied materials science polymer synthesis. Herein, we explore potential of topochemical for controlling emergence supramolecular chirality precise fabrication chiroptical materials. Boronic acid pinacol esters (BPin) were conjugated to naphthalimides containing an inherent chiral cholesteryl group linked by alkyl or benzene spacers. The BPin segments oxidized H2O2 form hydroxyl groups, enhanced luminescence, reduced steric effects, increased amphiphilicity. liposomal aggregates underwent situ oxidation transformed into 1D nanoarchitectures, exhibiting macroscopic chirality, active Cotton circularly polarized luminescence. Oxidation could also initiate intimate interplay between building units guest molecule, evolution multiple component assembly system realized.

Language: Английский

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FRET endows rare earth Eu(III) complex with stable ultra-dissymmetry and narrowband circularly polarized luminescence

Science China Materials, Journal Year: 2024, Volume and Issue: 68(3), P. 879 - 887

Published: Dec. 18, 2024

Language: Английский

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