A series of Fréchet-type dendrimers with 9-benzyloxymethylanthracene cores were synthesized and characterized. The chiral source for the dendrimers was an (S)-2-methyl-1-butoxy group in the 3-position of the benzene ring. Irradiation at 366 nm of a dilute benzene solution led to the formation of two diastereomers (1:1) through a quantitative intramolecular [4pi+4pi] cycloaddition between the central anthracene ring and the neighboring benzene ring. The process can be reversed with 254 nm UV light or heat. The benzene rings in the dendrons work as a light-harvesting system. The optical rotation values measured for the reversible process showed fatigue resistance. Thus, a promising new type of chiroptical switch has been created that has optical rotation values as output signals.
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http://dx.doi.org/10.1002/asia.201000159 | DOI Listing |
Small
December 2024
School of Physical Science and Technology, ShanghaiTech University, 393 Huaxia Middle Rd. Pudong, Shanghai, 201210, P. R. China.
ACS Appl Bio Mater
December 2024
Department of Chemistry, Indian Institute of Technology, Kharagpur, West Bengal 721302, India.
Blue-emissive nitrogen-doped chiral carbon dots (d-NCD230 and l-NCD230) exhibiting antipodal chiroptical activity, synthesized from the thermal pyrolysis of citric acid and d/l-aspartic acid in 1:2 molar ratios, have been explored as chirality-based fluorescent turn-off/on probes for the detection of Hg and l-cysteine (l-Cys). Circular dichroism (CD) spectroscopy revealed that the chiroptical activity originates from a synergy among intrinsic chirality, chiral precursors on the NCD surface, and hybridization of lower energy levels within the embedded chiral chromophore. Quantitative analysis of optical asymmetry using the Kuhn asymmetry factor () at the CD signal of 312 nm showed a higher value for d-NCD230 (1.
View Article and Find Full Text PDFNanoscale
December 2024
Materials Genome Institute, Shanghai Engineering Research Center of Organ Repair and Shanghai Engineering Research Center for Integrated Circuits and Advanced Display Materials, Shanghai University, Shanghai 200444, China.
Circularly polarized luminescence (CPL) is a fascinating luminescence phenomenon that has garnered significant research attention for chiroptical applications. In this study, we developed a highly sensitive chiroptical sensor by co-assembling G-quartet nanofibers and nonchiral nitrogen sulfur-doped carbon dots (N-S-CDs) for dual ion detection. The N-S-CDs were synthesized using the one-step microwave method, and a helical G-quartet-based nanofiber structure (g-fiber) was simultaneously formed from guanosine 5'-monophosphate (GMP) in the presence of Sr.
View Article and Find Full Text PDFJACS Au
November 2024
College of Chemistry, Zhengzhou University, Zhengzhou 450001, China.
The development of chiroptical molecular switches for chiral sensing, data communication, optical displays, chiral logic gates, and asymmetric catalysis is currently a vibrant frontier of science and technology. Herein, we report a practical artificial dynamic system based on a 1,2-diaxial atropisomer. Organocatalytic parallel kinetic resolution allows the divergent synthesis of two sets of stereoisomers with vicinal C-C and N-N axes from the same racemic single-axis substrates.
View Article and Find Full Text PDFChem Sci
January 2025
Department of Chemistry, University at Albany, State University of New York Albany NY 12222 USA
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