Osamu Sato

Photoinduced magnetization was observed in a Prussian blue analog, K0.2Co1.4- [Fe(CN)6]·6.9H2O. An increase in the critical temperature from 16 to 19 kelvin was observed as a result of red light illumination. Moreover, the magnetization in the ferrimagnetic region below 16 kelvin was substantially increased after illumination and could be restored almost to its original level by thermal treatment. These effects are thought to be caused by an internal photochemical redox reaction. Furtherm

The magnetic properties of many magnetic materials can be controlled by external stimuli. The principal focus here is on the thermal, photochemical, electrochemical, and chemical control of phase transitions that involve changes in magnetization. The molecular compounds described herein range from metal complexes, through pure organic compounds to composite materials. Most of the Review is devoted to the properties of valence-tautomeric compounds, molecular magnets, and spin-crossover complexes,

Molecular-based ferrimagnetic thin films with high critical temperatures ( T c ) composed of mixed-valence chromium cyanides were synthesized by means of a simple electrochemical route. The highest T c was 270 K, obtained for Cr 2.12 (CN) 6 . The T c values were easily controlled by changing the preparation conditions. Moreover, a reversible shift of T c could be electrochemically induced. As a result of such electrochemical control, these cyanides can be switched reversibly back and forth betwe

A possible route to finding new optically switchable molecular solids is to investigate the photoeffects of compounds that exhibit an abrupt phase transition or hysteresis loop. Such compounds must possess at least bistable states that are separated by a potential barrier in free energy. In fact, on the basis of this idea, we have recently succeeded in identifying three kinds of optically switchable molecular compounds. These include an Fe(III) spin-crossover complex exhibiting light induced exc

Two kinds of cobalt-iron cyanides (Rb(0.66)Co(1.25)[Fe(CN)(6)].4.3H(2)O and Co(1.5)[Fe(CN)(6)].6H(2)O) with different electronic structures have been investigated to understand the photoinduced long-range magnetic ordering. Rb(0.66)Co(1.25)[Fe(CN)(6)].4.3H(2)O produces a photomagnetic effect, whereas Co(1.5)[Fe(CN)(6)].6H(2)O does not respond to light. FT-IR and Mössbauer studies revealed that their oxidation states are expressed as Rb(0.66)Co(III)(0.84)Co(II)(0.41)[Fe(II)(CN)(6)] and Co(II)(1.5

The structural blue color of a Morpho butterfly originates from the diffraction of light and interference effects due to the presence of the microstructures on the wing of the butterfly. Structural color on the surface of a damselfish reversibly changes between green and blue. Inspired by these creatures, we have been trying to prepare high-quality and functional structural color films. We describe our efforts in this Account. A useful technique to prepare such structural color films in colloida

Abstract Man kennt eine Vielzahl magnetischer Materialien, deren magnetische Eigenschaften durch externe Stimuli geschaltet werden können. Das Hauptaugenmerk liegt auf der thermischen, photochemischen, elektrochemischen und chemischen Steuerung von Phasenübergängen, die mit einem Wechsel der Magnetisierung einhergehen. Die Bandbreite der beschriebenen Spezies reicht von Metallkomplexen über rein organische Verbindungen bis zu Kompositmaterialien, wobei der Schwerpunkt dieses Aufsatzes auf den Ei

A number of photofunctional molecular compounds have been developed recently. Typical examples of these are phototunable valence tautomeric compounds, which are now attracting great attention. When the charge-transfer bands of some Co valence tautomeric compounds are excited at low temperature, metastable redox isomers can be created after irradiation. The lifetimes of the metastable states can be more than several hours. These transformations can involve changes in the magnetic properties of th

Abstract The electrochemical, photochemical and chemical control of the magnetic properties in molecular compounds is described. The preparation of various thin films of CrCr and FeFe Prussian blue on a conducting electrode allowed us to control the magnetic properties by varying the oxidation state of the component metals. The magnetic properties of CrCr Prussian blue show that the critical temperature and coercive field can be drastically modified by electrochemical treatment. That is, the com

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Reversible photoinduced magnetization was observed in a cobalt iron cyanide thin film. Magnetic properties of the prussian blue analog, , can be switched between ferrimagnetic and paramagnetic by visible and near‐IR light illumination. The critical temperature after illumination was about 26 K. This material, obtained via an electrochemical route in the form of thin films on an electrode, provides a new system whose magnetic properties can be controlled by both photochemical and electrochemical

Here, we use a pyridinecarbaldehyde rhodamine 6G hydrazone ligand (L) to synthesize an Fe(II) complex 1 for the search of new fluorescent-spin crossover (SCO) materials. Single-crystal structural determinations suggest that the Fe(II) ion is chelated by two ring-opened ligands (L-o) to form a FeN₄O₂ coordination environment, and intermolecular π---π contacts of the xanthene groups connect the adjacent molecules to form a supramolecular one-dimensional chain. Magnetic suscep

Charge-transfer-induced spin transition occurs cooperatively and reversibly in the isolated FeIII2CoII chains of {[Fe(pzTp)(CN)3]2Co(4-styrylpyridine)2}⋅2 H2O ⋅2 CH3OH (1). When 1 is irradiated with 532 nm light, it shows single-chain magnetic behavior with no antiferromagnetic ordering after irradiation (see picture; C gray, N blue, B yellow; LS=low spin, HS=high spin).