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Open Access Research Article Just Accepted
Enantiomeric discrimination by UV-Vis-absorption chiral anisotropy of chiral nanostructured Au particles
Nano Research
Available online: 07 March 2025
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Enantiomeric discrimination plays a crucial role in various scientific domains, including analytical chemistry, chemical biology, pharmaceuticals, and pesticide research. A variety of theoretical frameworks and chiroptical spectroscopic methods, including optical rotation and circular dichroism, have been devised to identify and quantify enantiomers. Generally, circularly polarized light is utilized to determine the absolute configuration and composition of enantiomers. However, these techniques are not suitable for racemic mixtures or substances with minimal optical activity. Herein, we propose that UV-Vis absorption-chiral anisotropy (UV-Vis-ChA) of chiral nanostructured Au particles (CNAPs) can be utilized for enantiomeric discrimination, using amino acids as a model system. The CNAPs, synthesized via a seed-mediated method using chiral glutathione as the symmetry-breaking agent, exhibit a helical nanocubic structure. Upon the addition of amino acid enantiomers to the CNAPs solution, the decrease in the UV-Vis absorbance of CNAPs solution, with varying rates, was induced by enantiomers with different enantiomeric excess (ee) values. The rate constant of absorbance decrease (kΔ) was proportional to the ee values, regardless of polarity, size, or chromophore type. It is speculated that the UV-Vis-ChA results from the selective aggregation of CNAPs due to the formation of coordination bonds with enantiomers driven by their spin polarizations. This work provides a cost-effective, broad-spectrum, and quantitative approach to enantiomeric discrimination.

Communication Issue
Spin chiral anisotropy of diamagnetic chiral mesostructured In2O3 films
Nano Research 2024, 17(8): 7756-7761
Published: 22 June 2024
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Downloads:51

Spin chiral anisotropy (SChA) refers to the occurrence of different spin polarization in antipodal chiral structures. Herein, we report the SChA in diamagnetic chiral mesostructured In2O3 films (CMIFs) with manifestation of chirality-dependent magnetic circular dichroism (MCD) signals. CMIFs were grown on fluorine-doped tin dioxide conductive glass (FTO) substrates, which were synthesized via a hydrothermal route, with malic acid used as the symmetry-breaking agent. Two levels of chirality have been identified in CMIFs: primary nanoflakes with atomically twisted crystal lattices and secondary helical stacking of the nanoflakes. CMIFs exhibit chirality-dependent asymmetric MCD signals due to the different interactions of chirality-induced effective magnetic field and external magnetic field, which distinguish from the commonly observed external magnetic field-dependent symmetric MCD signals. These findings provide insights into spin manipulation of spin-paired diamagnets.

Research Article Issue
Chiral mesostructured hematite with temperature-independent magnetism due to spin confinement
Nano Research 2024, 17(3): 2019-2024
Published: 08 September 2023
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Hematite (α-Fe2O3) is known to undergo conversion from weak ferromagnetic to antiferromagnetic as the temperature decreases below the Morin temperature (TM = 250 K) due to spin moment rotation occurring during the Morin transition (MT). Herein, we endowed hematite with mesostructured chirality to maintain weak ferromagnetism without MT. Chiral mesostructured hematite (CMH) nanoparticles were prepared by a hydrothermal method with glutamic acid (Glu) as the symmetry-breaking agent. The triangular bipyramidal CMH nanoparticles were composed of helically cleaved nanoflakes with twisted crystal lattice. Field-cooled (FC) magnetization measurements showed that the magnetic moments of CMH were stabilized without MT within the temperature range of 10–300 K. Hysteresis loop measurements confirmed the weak ferromagnetism of CMH. The enhanced Dzyaloshinskii–Moriya interaction (DMI) was speculated to be responsible for the temperature-independent weak ferromagnetism, in which the spin configuration would be confined with canted antiferromagnetic coupling due to the mesostructured chirality of CMH.

Research Article Issue
Insight on metal ions inducing chiral self-assembly of DNA in silica mineralization
Nano Research 2023, 16(3): 3998-4003
Published: 17 June 2022
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Downloads:38

The self-assembly of DNA provides an attractive approach to understanding structural formation mechanism in living organisms and to assisting applications in materials chemistry. Herein, we investigated the effect of metal ions on chiral self-assembly of DNA through the synthesis of chiral mesostructured silica via self-assembly of metal ions, DNA, and silica source. 31 types of multivalent cationic metal ions were found to induce formation of chiral impeller-like DNA-silica complexes due to the chiral stacking of DNA. The strength of the interaction between the metal ion and phosphate group of DNA was speculated for the chiral stacking of DNA due to close distance of adjacent DNA to assure mutual recognition. Theoretical calculations indicated that chiral packing of DNA depends on the stability of the bridging phosphate-metal ion-phosphate bonds of DNA based on electron delocalization in d-orbital conjugation of metal ions.

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