How did the collaborationo nt his project start? This work is ac ollaboration between two research groups in Waseda University (Kuroda-Shimojima-Wada Laboratory,w ith an interest in the synthesis of inorganic solids from molecular precursors) and the University of To kyo (Mizuno-Yamaguchi Laboratory, with an interest in the catalysis of metal oxide cluster compounds like polyoxometalates). The collaboration started when one of the authors (Y.K.) moved between these groups. During many discussions , we came to the idea that several polyoxometalates can be regarded as building blocks of inorganic solids, and techniques developed specially for the chemical design of polyoxometalates can also be applied to inorganic solids like brucite-type layered metal hydroxides. Thus, we succeeded in establishing the novel synthetic concept of hybrid metal hydroxide nanosheets by combining the chemistries of layered metal hydroxides and polyoxometalates. What is the most significant result of this study? The modification reaction developed in this study can be applied to aw ide range of materials, in terms of constituent metallic elements of metal hydroxide nanosheets and those of surface functional groups. Because tripodal ligands have flexible tridentate binding sites, they can adjust their conformations to metal hydrox-ide nanosheets with different lattice constants;t his is expressed by the phrase "one-size-fits-all modifier" in the title. What was the inspiration for this cover design? The cover design was inspired by the Japanese Sushi culture. We enjoy various fishes in as tandardized style, in which as lice of af ish is placed on av inegared rice ball. In this study,w ec an provide various metal hydroxide nanosheets in as tandardized method. The future goal of this study will be the production of designed nanosheets which satisfy the demands of functional devices , in the same way as aS ushi master makes flavored Sushi that fits the customer's taste. Invited for the cover of this issue is the group of Yoshiyuki Kuroda and Kazuyuki Kuroda at the Waseda University in Tokyo. The image depicts how the production of diverse metal hydroxide nanosheets can be standardized in the same way as Sushi. Read the full text of the article at

Layered magnesium hydroxides modified organically with tris(hydroxymethyl)aminomethane (Tris-NH) were directly synthesized from magnesium chloride dissolved in a polar organic solvent, like dimethyl sulfoxide (DMSO), containing a small amount of water. Tris-NH acted as a base for precipitating magnesium hydroxides as well as an organic modifier. In contrast to the case of an aqueous solution, the use of organic solvents substantially increased the degree of modification of layered magnesium hydroxides with Tris-NH owing to the formation of bidentate Mg-O-C linkages by Tris-NH in addition to its tridentate bonding mode. Bidentate linkages, hydrolyzed readily in water, are stable in the organic media. Pentaerythritol (Tris-CHOH), trimethylolethane (Tris-CH), and trimethylolpropane (Tris-CH) were also successfully used for the synthesis of organically-modified layered magnesium hydroxides by the addition of tetrabutylammonium hydroxide as a base with DMSO as the solvent. The synthesis of hybrid magnesium hydroxides in organic solvents is expected to expand the chemistry of organically modified layered metal hydroxides with various metallic species and a wide variety of organic functional groups.

Precise size control of layered double hydroxide nanoparticles (LDHNPs) is crucial for their applications in anion exchange, catalysis, and drug delivery systems. Here, we report the synthesis of LDHNPs through a reconstruction method, using tripodal ligands (e.g., tris(hydroxymethyl)aminomethane; THAM). We found that the mechanism of reconstruction at least includes a dissolution-recrystallization process rather than topotactic transformation. THAM is immobilized on the surface of recrystallized LDHNPs with tridentate linkages, suppressing their crystal growth especially in lateral directions. The particle size of the LDHNPs is precisely controlled by the concentration of THAM regardless of the synthetic routes, such as coprecipitation and reconstruction. It is suggested that the particle size is controlled on the basis of Ostwald ripening which is governed by the equilibrium of the surface modification reaction.

Layered double hydroxides (LDHs) have occupied an important place in the fields of catalysts, electrocatalysts, and fillers, and their applicability can be greatly enhanced by interlayer organic modifications. In contrast to general organic modification based on noncovalent modification using ionic organic species, this study has clarified in situ interlayer covalent modification of LDH nanoparticles (LDHNPs) with the tripodal ligand tris(hydroxymethyl)aminomethane (Tris-NH 2 ). Interlayer-modified CoAl LDHNPs were obtained by a one-pot hydrothermal treatment of an aqueous solution containing metal salts and Tris-NH 2 at 180 °C for 24 h. Tris-NH 2 was covalently bonded on the interlayer surface of LDHNPs. Interlayer-modified NiAl LDHNPs were also similarly synthesized. Some comparative experiments under different conditions indicate that the important parameters for interlayer modification are the number of bonding sites per a modifier, the electronegativity of a constituent divalent metal element, and the concentration of a modifier; this is because these parameters affect the hydrolytic stability of alkoxy−metal bonds between a modifier and a layer of LDHNPs. The synthesis of interlayer-modified MgAl LDHNPs was achieved by adjusting these parameters. This achievement will enable new potential applications because modification of only the outer surface has been achieved until now. Interlayer-modified LDHNPs possessing CO 3 2− in the interlayer space were delaminated into monolayers under ultrasonication in water. The proposed method provides a rational approach for interlayer modification and facile delamination of LDHNPs.

Conventional top-down methods for preparing inorganic nanosheets possess fundamental challenges of morphological control. Herein, the direct synthesis of organically modified single-layer magnesium hydroxide nanosheets with narrow size distribution was achieved...