Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

Titanium Dioxide Nanomaterials: Synthesis, Properties, Modifications, and Applications

Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

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Dye-Sensitized Solar Cells

J. Appl. Cryst.の発刊に際して

The long-standing challenge of designing and constructing new crystalline solid-state materials from molecular building blocks is just beginning to be addressed with success. A conceptual approach that requires the use of secondary building units to direct the assembly of ordered frameworks epitomizes this process: we call this approach reticular synthesis. This chemistry has yielded materials designed to have predetermined structures, compositions and properties. In particular, highly porous frameworks held together by strong metal-oxygen-carbon bonds and with exceptionally large surface area and capacity for gas storage have been prepared and their pore metrics systematically varied and functionalized.

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Reticular synthesis and the design of new materials

The preparation and characterization of [Co II-HS (dpa)(3,5-DBSQ) 2 ] are presented first time. From the magnetic curve, the phase transition temperatures, T c is 380 K. To our knowledge, the T c value is the highest among the species exhibiting thermal valence tautomerism. After illumination with 532 nm light at 5 K, the magnetization values increase from μ eff =1.73 to 2.0 μ B , showing valence tautomerism. The metastable state will recover to the original state with the increase of temperature. The alternate illumination with 532 and 830 nm light at 5 K can induce a reversible change in magnetization. The quick response to light means that this compound can be used for the development of optical–magnetic switch.

Novel Co complex with high transformation temperature of valence tautomerism

A one-dimensional homochiral MoIVCuII compound, [Cu(tren)][Cu(33)][Mo(CN)8]·4H2O (1, tren = tris(2-aminoethyl)amine, 33 = bis(3-aminopropyl)amine), was synthesized and characterized. Compound 1 experiences spontaneous resolution from achiral components and crystallized in a chiral space group P21. It exhibits photomagnetism via photoinduced metal-to-metal charge transfer, making it a novel example of multifunctional molecule-based materials.

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A one-dimensional homochiral Mo(IV)-Cu(II) coordination polymer: spontaneous resolution and photoresponsive properties

The photoswitchable magnetic thin films have been designed by alternate depositions of bipolar amphiphilic azobenzene and Fe 3 O 4 nanoparticles by using the layer-by-layer adsorption technique. In these films, reversible photoisomerizations of the azobenzene chromophore affected the electrostatic interaction between the azobenzene chromophore and the surface of Fe 3 O 4 nanoparticles. As a result, we have succeeded in controlling the magnetization of these films by photoillumination at room temperature.

Photoswitchable magnetic layer-by-layer films consisting of azobenzene derivatives and iron oxide nanoparticles

A self-assembled cobalt molecular grid of a pyrazine-bridged bis-tridentate ligand (LR), where R = H (1), CH3 (2), and Br (3), was prepared and structurally characterized. Depending on the electronic effects of the substituents on the ligand, the redox of the metal center was systematically modulated, and the magnetic behavior from essentially high-spin CoII in 3 versus completely diamagnetic CoIII in 1 to CoII spin-crossover in 2 can be achieved.

Redox Modulation of Spin Crossover within a Cobalt Metallogrid.

The authors describe their experience with ten cases of brain tumors in children in whom the onset of symptoms occurred within the first year of life, but who were operated on when they were 2 months

Osamu Sato

Papers

Novel Co complex with high transformation temperature of valence tautomerism

A one-dimensional homochiral Mo(IV)-Cu(II) coordination polymer: spontaneous resolution and photoresponsive properties

Photoswitchable magnetic layer-by-layer films consisting of azobenzene derivatives and iron oxide nanoparticles

Redox Modulation of Spin Crossover within a Cobalt Metallogrid.

Brain tumors of early infants.