Self-Assembled Chiral Nanoparticle Superstructures and Identification of Their Collective Optical Activity from Ligand Asymmetry

Chiral Transfer and Evolution in Cysteine Induced Cobalt Superstructures

Chiral organic additives have unveiled the extraordinary capacity to form chiral inorganic superstructures, however, complex hierarchical structures have hindered the understanding of chiral transfer and growth mechanisms. This study introduces a simple hydrothermal synthesis method for constructing chiral cobalt superstructures with cysteine, demonstrating specific recognition of chiral molecules and outstanding electrocatalytic activity. The mild preparation conditions allow in situ tracking of chirality evolution in the chiral cobalt superstructure, offering unprecedented insights into the chiral transfer and amplification mechanism. The resulting superstructures exhibit a universal formation process applicable to other metal oxides, extending the understanding of chiral superstructure evolution. This work contributes not only to the fundamental understanding of chirality in self-assembled structures but also provides a versatile method for designing chiral inorganic nanomaterials with remarkable molecular recognition and electrocatalytic capabilities.

A cooperation tale of biomolecules and nanomaterials in nanoscale chiral sensing and separation

The cooperative relationship between biomolecules and nanomaterials makes up a beautiful tale about nanoscale chiral sensing and separation. Biomolecules are considered a fabulous chirality 'donor' to develop chiral sensors and separation systems. Nature has endowed biomolecules with mysterious chirality. Various nanomaterials with specific physicochemical attributes can realize the transmission and amplification of this chirality. We focus on highlighting the advantages of combining biomolecules and nanomaterials in nanoscale chirality. To enhance the sensors' detection sensitivity, novel cooperation approaches between nanomaterials and biomolecules have attracted tremendous attention. Moreover, innovative biomolecule-based nanocomposites possess great importance in developing chiral separation systems with improved assay performance. This review describes the formation of a network based on nanomaterials and biomolecules mainly including DNA, proteins, peptides, amino acids, and polysaccharides. We hope this tale will record the perpetual relation between biomolecules and nanomaterials in nanoscale chirality.

Versatile fabrication of metal sulfide supraparticles by an in situ decomposition-assembly strategy

Supraparticles (SPs) are of great importance in both fundamental and applied studies due to their emerging collective properties, synergistic effects, and various applications. Metal sulfide nanomaterials are of vital importance in biomedicine, catalysis, battery materials, and other fields. Herein, an in situ decomposition-assembly strategy for the versatile fabrication of metal sulfide SPs is developed. In the fabrication, cysteine molecules and metal cations first react and form coordination polymers, which are then decomposed by heating to produce small-sized metal sulfide nanocrystals. Driven by elimination of the high surface energy of NCs generated by thermal decomposition and the van der Waals attraction, the resulting nanocrystals in situ self-assemble each other and form SP products. In addition to homogeneous Cu2S, CdS, and ZnS products, the proposed system can even be extended to fabricate hybrid Cu2S/Fe2O3 SPs. Furthermore, the SP size can be easily tuned from 10 to 100 nm by adjusting the proportion of cysteine and metal ions. The SPs not only exhibit various properties including photothermal conversion, fluorescence, and magnetism, depending on their composition, but can also combine these properties by the formation of hybrid structures.

Unconventional-Phase Crystalline Materials Constructed from Multiscale Building Blocks

Crystal phase, an intrinsic characteristic of crystalline materials, is one of the key parameters to determine their physicochemical properties. Recently, great progress has been made in the synthesis of nanomaterials with unconventional phases that are different from their thermodynamically stable bulk counterparts via various synthetic methods. A nanocrystalline material can also be viewed as an assembly of atoms with long-range order. When larger entities, such as nanoclusters, nanoparticles, and microparticles, are used as building blocks, supercrystalline materials with rich phases are obtained, some of which even have no analogues in the atomic and molecular crystals. The unconventional phases of nanocrystalline and supercrystalline materials endow them with distinctive properties as compared to their conventional counterparts. This Review highlights the state-of-the-art progress of nanocrystalline and supercrystalline materials with unconventional phases constructed from multiscale building blocks, including atoms, nanoclusters, spherical and anisotropic nanoparticles, and microparticles. Emerging strategies for engineering their crystal phases are introduced, with highlights on the governing parameters that are essential for the formation of unconventional phases. Phase-dependent properties and applications of nanocrystalline and supercrystalline materials are summarized. Finally, major challenges and opportunities in future research directions are proposed.

Complexation Reaction-Based Two-Dimensional Luminescent Crystalline Assembly of Atomic Clusters for Recyclable Storage of Oxygen

In this work, we report storage of oxygen in two-dimensional (2D) crystalline nanosheets comprising luminescent gold nanoclusters (Au NCs). Complexation reaction between Au NCs (stabilized by l-phenylalanine and mercaptopropionic acid) and zinc ions led to the formation of crystalline assembly of Au NCs. The crystalline nature of the assembly of Au NCs was confirmed through transmission electron microscopy (TEM), high-resolution TEM, and selected area electron diffraction (SAED) analysis. Atomic force microscopy (AFM) analysis, in conjunction with field emission scanning electron microscopy (FESEM) analysis, confirmed the 2D nature of the assembly of the Au NCs. The 2D crystalline nanosheets formed out of reaction between Au NCs and Zn²⁺ were found to be of near-uniform thickness, with an average value of 3.8 ± 1.65 nm. These 2D nanosheets constituting of hierarchically organized Au NCs were further used for reversible storage of oxygen at ambient conditions of 20 °C and 20 bar pressure.