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495 results on '"Takamizawa, Satoshi"'

7. Structural and Thermal Diffusivity Analysis of an Organoferroelastic Crystal Showing Scissor-Like Two-Directional Deformation Induced by Uniaxial Compression

Author

Ranjan, Subham, primary, Ryu, Meguya, additional, Morioka, Ryota, additional, Kamegaki, Shuji, additional, Ng, Soon Hock, additional, Smith, Daniel, additional, Vongsvivut, Jitraporn, additional, Tobin, Mark J., additional, Juodkazis, Saulius, additional, Morikawa, Junko, additional, and Takamizawa, Satoshi, additional

Published
2023
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9. Assembling of a Water‐Soluble N^C^N‐Coordinated Pt(II) Complex Aggregate Assisted by Carbon Dioxide in Basic Aqueous Solution.

Author

Mita, Hiroyuki, Hattori, Shingo, Sasaki, Toshiyuki, Takamizawa, Satoshi, and Shinozaki, Kazuteru

Subjects
PLATINUM, AQUEOUS solutions, CARBON dioxide, SINGULAR value decomposition, CHARGE-transfer transitions, X-ray crystallography
Abstract

We report an unprecedented result of self‐aggregation of [Pt(L1)Cl] (HL1=1,3‐di(5‐carboxy‐2‐pyridyl)benzene) triggered by CO2 in basic aqueous solution. The color of basic aqueous solution containing [Pt(L1)Cl] changes from yellow to blue‐green during the aggregation resulted from a reaction with CO2 in air. Upon CO2 gas bubbling, strong and broad absorption bands of aggregate assigned to the metal‐metal‐to‐ligand charge‐transfer transition appeared at 701 and 1152 nm. Recrystallization of [Pt(L1)Cl] from Na2CO3 aqueous solution afforded polymorphic crystals of red and blue‐green forms. A single X‐ray crystallography revealed that the red form of crystal consists of a Pt−Pt stacked dimer bridged by CO32− ion and one of the carboxy groups of L1 is deprotonated. An elemental analysis provided evidence that the blue‐green crystal is constructed by linear array consisting of the [Pt(L2)(CO3)]3− (HL2=1,3‐di(5‐carboxylate‐2‐pyridyl)benzene) units. The formation process of blue‐green aggregate in aqueous solution was monitored through a transient absorption spectrum, and the absorption of aggregates involved in the spectral change were examined by a global analysis. A singular value decomposition and kinetic analysis provide that there are four species resulted from the self‐assembling reaction in the solution and the maximal degree of aggregation is at least 32‐mer. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Solid state 1H, 7Li, and 13C NMR studies on new ionic plastic crystals of crown ether–Li-TFSA complexes.

Author

Kobayashi, Akira, Yamagami, Jun, Ranjan, Subham, Takamizawa, Satoshi, and Honda, Hisashi

Abstract

This study provides the first evidence that a Li ion can form ionic plastic crystals using crown ether with a bis-(trifluoromethanesulphonyl) amide (TFSA) anion. 1H, 7Li, and 13C nuclear-magnetic-resonance (NMR) measurements of the 15-crown-5–Li-TFSA complex revealed that the constituents underwent isotropic reorientation in the plastic crystalline phase. The NMR data of the 12-crown-4–Li-TFSA salt showed that the complex is a rotator crystal (the complexes are denoted as [Li 15C5] and [Li 12C4] in this paper). The X-ray diffraction (XRD) reflection patterns of the [Li 15C5] crystal recorded in the highest-temperature solid phase (plastic phase) could be indexed to a cubic structure. Conversely, [Li 12C4] could be fitted to a trigonal structure. In this study, [M (3n)Cn] (M = Li, Na, K; n = 4–6) complexes were also prepared, and NMR, DSC, XRD, and electrical conductivity measurements were performed. Based on these results, we additionally revealed that the [Na 15C5] and [K (15C5)2] complexes are also new rotator crystals. Single-crystal XRD measurements also revealed that the [Na 15C5] compound has two stable sites in the crystal. Activation energies of molecular motions in the [M (3n)Cn] crystals were estimated using 1H NMR relaxation time (T1 and T2) measurements. The electrical conductivity measurements of [Li 12C4], [Li 15C5], and [Na 15C5] showed high ionic conductivities (∼10−2 S cm−1). [ABSTRACT FROM AUTHOR]

Published
2023
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12. Evaluation of the tacrolimus treatment using euploid blastocyst for women with repeated implantation failures showing elevated type-1 helper T (Th1)/Th2 cell ratios

Author

Nakagawa, Koji, primary, Kuroda, Keiji, additional, Shiobara, Keisuke, additional, Ishiyama, Shunsuke, additional, Nakao, Kazuki, additional, Horikawa, Takashi, additional, Kataoka, Hisayo, additional, Takamizawa, Satoshi, additional, Kwak-Kim, Joanne, additional, and Sugiyama, Rikikazu, additional

Published
2023
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22. Mechanical deformation and multiple thermal restoration of organic crystals: reversible multi-stage shape-changing effect with luminescence-color changes

Author

Feng, Chi, Seki, Tomohiro, Sakamoto, Shunichi, Sasaki, Toshiyuki, Takamizawa, Satoshi, 1000090282300, Ito, Hajime, Feng, Chi, Seki, Tomohiro, Sakamoto, Shunichi, Sasaki, Toshiyuki, Takamizawa, Satoshi, 1000090282300, and Ito, Hajime

Abstract

Shape-memory materials can be mechanically deformed and subsequently reverse the deformation upon changing the temperature. Shape-memory materials have attracted considerable attention for basic research and industrial applications, and polymer and alloy shape-memory materials have been well studied; however, it is formidably challenging to develop functional shape-memory materials, such as materials with multi-stage and anisotropic shape changes and shape changes accompanied by changes in color and light emission. Here, we found a reversible multi-stage shape-changing effect after mechanical deformation in a molecular crystal induced by multi-step thermal phase transitions with reversible shape changes and luminescence-color changes. Using single-crystal structure and thermal analyses as well as mechanical property measurements, we found that the reversible multi-stage shape-changing effect was achieved by a combination of a twinning deformation and multi-step thermal phase transitions. The changes in the crystal shape and luminescence suggest novel strategies for imparting known shape-memory materials with additional functionalities.

Published
2022

36. The mechanism of bending in a plastically flexible crystal

Author

Bhandary, Subhrajyoti, Thompson, Amy J., McMurtrie, John C., Clegg, Jack K., Ghosh, Peuli, Mangalampalli, S. R.N.Kiran, Takamizawa, Satoshi, Chopra, Deepak, Bhandary, Subhrajyoti, Thompson, Amy J., McMurtrie, John C., Clegg, Jack K., Ghosh, Peuli, Mangalampalli, S. R.N.Kiran, Takamizawa, Satoshi, and Chopra, Deepak

Abstract

Mechanically adaptable molecular crystals have potential applications in flexible smart materials and devices. Here, we report the mechanism of plastic deformation in single crystals of a small organic molecule (N-(4-ethynylphenyl)-3-fluoro-4-(trifluoromethyl)benzamide) that can be repeatedly irreversibly bent and returned to its original shape without concomitant delamination or loss of integrity. Along with the quantification of the crystals' local and bulk mechanical properties (hardness, indentation modulus and Young's modulus), micro-focus synchrotron X-ray diffraction mapping show that upon deformation, molecular layers lined with trifluoromethyl groups cooperatively slip past one another resulting in their impressive plastic malleability.

Published
2020

37. Photoluminescent Ferroelastic Molecular Crystals

Author

1000050638187, Seki, Tomohiro, Feng, Chi, Kashiyama, Kentaro, Sakamoto, Shunichi, Takasaki, Yuichi, Sasaki, Toshiyuki, Takamizawa, Satoshi, 1000090282300, Ito, Hajime, 1000050638187, Seki, Tomohiro, Feng, Chi, Kashiyama, Kentaro, Sakamoto, Shunichi, Takasaki, Yuichi, Sasaki, Toshiyuki, Takamizawa, Satoshi, 1000090282300, and Ito, Hajime

Abstract

Ferroelasticity has been reported for several types of molecular crystals, which show mechanical-stress-induced shape change under twinning and/or spontaneous formation of strain. Aiming to create materials that exhibit both ferroelasticity and light-emission characteristics, we discovered the first examples of ferroelastic luminescent organometallic crystals. Crystals of arylgold(I)(N-heterocyclic carbene)(NHC) complexes bend upon exposure to anisotropic mechanical stress. X-ray diffraction analyses and stress-strain measurements on these ferroelastic crystals confirmed typical ferroelastic behavior, mechanical twinning, and the spontaneous build-up of strain. A comparison with single-crystal structures of related gold-NHC complexes that do not show ferroelasticity shed light on the structural origins of the ferroelastic behavior.

Published
2020

38. Photoluminescent Ferroelastic Molecular Crystals

Author

Seki, Tomohiro, Feng, Chi, Kashiyama, Kentaro, Sakamoto, Shunichi, Takasaki, Yuichi, Sasaki, Toshiyuki, Takamizawa, Satoshi, Ito, Hajime, Seki, Tomohiro, Feng, Chi, Kashiyama, Kentaro, Sakamoto, Shunichi, Takasaki, Yuichi, Sasaki, Toshiyuki, Takamizawa, Satoshi, and Ito, Hajime

Abstract

Ferroelasticity has been reported for several types of molecular crystals, which show mechanical-stress-induced shape change under twinning and/or spontaneous formation of strain. Aiming to create materials that exhibit both ferroelasticity and light-emission characteristics, we discovered the first examples of ferroelastic luminescent organometallic crystals. Crystals of arylgold(I)(N-heterocyclic carbene)(NHC) complexes bend upon exposure to anisotropic mechanical stress. X-ray diffraction analyses and stress-strain measurements on these ferroelastic crystals confirmed typical ferroelastic behavior, mechanical twinning, and the spontaneous build-up of strain. A comparison with single-crystal structures of related gold-NHC complexes that do not show ferroelasticity shed light on the structural origins of the ferroelastic behavior.

Published
2020

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