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

Incorporation of photochromic compounds into magnetic systems is one of the new strategies being implemented to realize the control of magnetic properties by photoillumination. We have designed composite materials comprising iron oxide particles and photochromic spiropyran vesicles as cast films on substrates. Photofunctional magnetic vesicles of amphiphilic spiropyran (SP1822) containing iron oxide particles exhibit superparamagnetic properties at room temperature. Both photoisomerization and photoinduced aggregation of the photoresponsive magnetic vesicles were observed, even without any supporting media such as solvents or polymer matrixes. As a result of the assembly of the vesicles, magnetic dipolar interactions among adjacent iron oxide particles were induced by photoillumination at room temperature, even in the solid state.

Magnetic Vesicles of Amphiphilic Spiropyran Containing Iron Oxide Particles on a Solid State Substrate

The 1-D compound [Fe(L)(CN)2][Mn(hfac)2] (1), which adopts the -NC-Fe-CN-Mn- heterometallic structure, has been shown to exhibit light-induced excited spin-state trapping effects. After illumination, anti-ferromagnetic coupling was observed between the iron(II) (S = 2) and manganese(II) (S = 5/2) ions.

Novel structural and magnetic properties of a 1-D iron(II)-manganese(II) LIESST compound bridged by cyanide.

The effects of pressure on valence tautomeric transitions of dinuclear cobalt complexes

http://pfwww.kek.jp/acr2001pdf/PartB/PF01UR070.pdf

Photo-induced magnetized state of Co(DTBSQ)(DTBCat)(phen) · C6H5CH3 studied by X-ray absorption spectroscopy

It is an ongoing challenge to design and synthesize magnetic materials that undergo colossal thermal expansion, which possess potential applications as microscale or nanoscale actuators with magnetic functionality. In this work, we use the paramagnetic metallocyanate building block to construct a cyanide bridged Fe−Co complex, which shows thermally induced intramolecuar charge transfer and rotation of building blocks. Metal-to-metal charge transfer between 180 and 240 K induced a volumetric thermal expansion coefficient of 1498 MK-¹, and spin transition with a hysteretic magnetic transition. Rotation of the magnetic building blocks induced change of π...π interactions, resulting in a negative volume expansion coefficient of −489 MK-¹, and another hysteretic magnetic transition between 300 and 350 K. The present work presents a strategy for incorporating both colossal positive and negative volumetric thermal expansion with shape and magnetic memory effects in a material.

Osamu Sato

Papers

Magnetic Vesicles of Amphiphilic Spiropyran Containing Iron Oxide Particles on a Solid State Substrate

Novel structural and magnetic properties of a 1-D iron(II)-manganese(II) LIESST compound bridged by cyanide.

The effects of pressure on valence tautomeric transitions of dinuclear cobalt complexes

Photo-induced magnetized state of Co(DTBSQ)(DTBCat)(phen) · C6H5CH3 studied by X-ray absorption spectroscopy

A Material Showing Colossal Positive and Negative Volumetric Thermal Expansion with Hysteretic Magnetic Transition.