370 results match your criteria: "Tsukuba Research Center[Affiliation]"

Monomeric tri-coordinated bis(ferrocenyl)haloalumanes.

Dalton Trans

January 2025

Graduate School of Science and Technology, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan.

The reactions of the sterically demanding ferrocenyl lithium dimer (Fc*Li) (Fc* = 2,5-bis(3,5-di--butyl-phenyl)-1-ferrocenyl) with aluminum trihalides (AlCl, AlBr, and AlI) to furnish the corresponding monomeric bis(ferrocenyl)haloalumanes are reported. In the case of the reaction with AlI, an unexpected intramolecular 1,1'-aluminum migration in the ferrocenyl moiety was found to occur. Their monomeric structures with a tri-coordinated aluminum atom show affinitive Al⋯Fe interactions.

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NLRP3 inflammasome inhibitor is a highly attractive drug target for the treatment of various inflammatory diseases. Here, we report the discovery of pyridazine derivatives as a new class of scaffold for NLRP3 inflammasome inhibitors. We optimized HTS hit 2a to improve both in vitro IL-1β inhibitory activity and the mean photo effect (MPE) value in the in vitro 3T3 neutral red uptake (NRU) phototoxicity test.

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Coexistence of the Radial-Guided Mode and WGM in Azimuthal-Grating-Integrated Microring Lasers.

ACS Photonics

December 2024

Graduate School and Faculty of Information Science and Electrical Engineering, Kyushu University, 744 Motooka Nishi-ku, Fukuoka, 819-0395, Japan.

Whispering-gallery mode (WGM) resonators, renowned for their high Q-factors and narrow line widths, are widely utilized in integrated photonics. Integrating diffraction gratings onto WGM cavities has gained significant attention because these gratings function as azimuthal refractive index modulators, enabling single-mode WGM emissions and supporting beams with orbital angular momentum (OAM). The introduction of curved grating structures facilitates guided mode resonances by coupling high-order diffracted waves with leaking modes from the waveguide.

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Optically Pumped and Electrically Switchable Microlaser Array Based on Elliptic Deformation and Q-Attenuation of Organic Droplet Oscillators.

Adv Mater

December 2024

Department of Materials Science, Institute of Pure and Applied Sciences, and Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8573, Japan.

Conventional laser panel displays are developed through the mass integration of electrically pumped lasers or through the incorporation of a beam steering system with an array of optically pumped lasers. Here a novel configuration of a laser panel display consisting of a non-steered pumping beam and an array of electrically Q-switchable lasers is reported. The laser oscillator consists of a robust, self-standing, and deformable minute droplet that emits laser through Whispering-Gallery Mode resonance when optically pumped.

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The bias-stress effects of bottom-gate top-contact polymer-based organic field-effect transistors (OFETs) with different channel lengths (50-500 μm) were evaluated by repeating cycles of prolonged on-state gate-bias application and transfer characteristics measurements in the linear regime. The thicknesses of poly(didodecylquaterthiophene--didodecylbithiazole) active layers were 26 and 37 nm. All OFETs exhibited nonlinear (nonideal) transfer characteristics with a maximum transconductance within the gate-source voltage sweep range.

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Like the crystallization of water to ice, magnetic transition occurs at a critical temperature after the slowing down of dynamically fluctuating short-range correlated spins. Here, we report a unique type of magnetic transition characterized by a linear increase in the volume fraction of unconventional static short-range-ordered spin clusters, which triggered a transition into a long-range order at a threshold fraction perfectly matching the bond percolation theory in a new quantum antiferromagnet of pseudo-trigonal Cu(OH)Cl. Static short-range order appeared in its Kagome lattice plane below ca.

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Bis(methylene)-λ-phosphane anions, , anionic phosphorus-centered heteroallene-type molecules, were obtained from the desilylation of a bis(silyl)methyl-substituted phosphaalkene. Their molecular structures, which were determined using spectroscopic techniques and single-crystal X-ray diffraction analysis, suggest that the central di-coordinated P atom is engaged in cumulative C[double bond, length as m-dash]P[double bond, length as m-dash]C π-bonds with the neighboring C atoms. The π-bond character of the C[double bond, length as m-dash]P[double bond, length as m-dash]C moieties was examined on the basis of the experimental results in combination with theoretical calculations; the results obtained suggest that multiple silyl substitutions at the C atom weaken the C[double bond, length as m-dash]P π-bonding character.

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Oxygen in solids usually exists in an O ionic state. As a result, it loses its magnetic nature of a single atom, wherein two unpaired electrons exist in its outer 2p orbitals. Here, it is shown that an unconventional stable ionic state of O is realized in a new semiconductor material SrAlO, leading to an intrinsic p-orbital ferromagnetism stable until ≈900 K.

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Interlayer Hydrogen Recombination from Hydrogen Boride Nanosheets Elucidated by Isotope Labeling.

J Phys Chem Lett

November 2024

Department of Materials Science, Institute of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.

In this study, deuterium boride (DB) nanosheets were synthesized as deuterated borophane through the ion exchange of magnesium cations in magnesium diboride with deuterons from a deuterium-type ion-exchange resin in acetonitrile. The Fourier-transform infrared absorption spectrum of DB exhibited clear isotope effects, namely the shift in the absorption peak of the B-H stretching vibrational mode to a lower wavenumber. Temperature-programmed desorption (TPD) from a mixture of DB and hydrogen boride (HB) nanosheets yielded a more intense hydrogen-deuterium (HD) signal compared to the H and D signals.

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Hydrogen boride (HB) sheets are emerging as a promising two-dimensional (2D) boron material, with potential applications as unique electrodes, substrates, and hydrogen storage materials. The 2D layered structure of HB was successfully synthesized using an ion-exchange method. The chemical bonding and structure of the HB sheets were investigated using Fourier Transform Infrared (FT-IR) spectroscopy and Transmission Electron Microscopy (TEM), respectively.

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Hydrogen Boride Sheets and Copper Nanoparticle Composites as a Visible-Light-Sensitive Hydrogen Release System.

Small

December 2024

Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8552, Japan.

Hydrogen boride (HB) sheet is a new class of 2D materials comprising hydrogen and boron, synthesized through ion-exchange and exfoliation techniques. HB sheets can release hydrogen (H) under light irradiation and is predicted to be a promising H storage material. However, its application is limited to the UV region.

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Visible-Light-Induced Hydrogen Generation from Mixtures of Hydrogen Boride Nanosheets and Phenanthroline Molecules.

Adv Sci (Weinh)

November 2024

Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8552, Japan.

Hydrogen boride (HB) nanosheets are recognized as a safe and lightweight hydrogen carrier, yet their hydrogen (H) generation technique has been limited. In the present study, nitrogen-containing organic heterocycles are mixed with HB nanosheets in acetonitrile solution for visible-light-driven H generation. After exploring various nitrogen-containing heterocycles, the mixture of 1,10-phenanthroline molecules (Phens) and HB nanosheets exhibited significant H generation even under visible light irradiation.

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Experimental and Theoretical Characterization of 4π-Electron Möbius Aromatic System of a 1,2-Digermacyclobutadiene.

Angew Chem Int Ed Engl

January 2025

Division of Chemistry, Institute of Pure and Applied Sciences, and Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8571, Japan.

Article Synopsis
  • The study visualizes the electron-density distribution in the 1,2-digermacyclobutadiene ring, highlighting its unique electron behavior.
  • The GeC ring exhibits a strong Möbius 4π-electron aromatic character, which is distinct from the antiaromatic nature of the all-carbon cyclobutadiene.
  • This research suggests that the presence of germanium alters the electronic properties significantly compared to the carbon-only structure.
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Regioselective Synthesis of Pyrrole-Based Poly(arylenevinylene)s via Mn-Catalyzed Hydroarylation Polyaddition.

Macromol Rapid Commun

October 2024

Institute of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8573, Japan.

Mn-catalyzed hydroarylation polyaddition of 1-(2-pyrimidinyl)pyrrole (1a) with aromatic diynes is investigated. The use of commercially available MnBr(CO) as a precatalyst under the optimized reaction conditions resulted in a site- and regioselective hydroarylation polyaddition, affording the corresponding poly(arylenevinylene)s (PAVs) with excellent vinylene selectivity. The reaction protocol eliminates the production of stoichiometric amounts of byproducts from the monomers.

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Access to clean water, hygiene, and sanitation is becoming an increasingly pressing global demand, particularly owing to rapid population growth and urbanization. Phytoremediation utilizes a highly conserved phytochelatin in plants, which captures hazardous heavy metal ions from aquatic environments and sequesters them in vacuoles. Herein, we report the design of phytochelatin-inspired copolymers containing carboxylate and thiolate moieties.

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Near-unity angular anisotropy of circularly polarized luminescence from microspheres of monodispersed chiral conjugated polymers.

Chem Commun (Camb)

July 2024

Department of Materials Science, Institute of Pure and Applied Sciences, and Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.

A microsphere, assembled from a chiral π-conjugated polymer with narrow polydispersity, features a well-organized twisted-bipolar structure and exhibits highly biased circularly polarized luminescence (CPL). The CPL emitted toward the equatorial direction is 61-fold greater than that emitted along the zenith direction, which is the highest anisotropy among existing microscopic CPL emitters.

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Article Synopsis
  • Cross-dehydrogenative coupling (CDC) reactions are highlighted as efficient methods for creating C-C bonds, with a recent focus on the selective reaction between naphthalene and fluorobenzene at the β-position.
  • The unique selectivity is driven by the reductive elimination process, influenced by the steric effects of the naphthyl group and the electron-withdrawing nature of fluorobenzene.
  • The findings indicate that regioselectivity in C-H functionalization of polycyclic aromatic hydrocarbons (PAHs) relies on the reductive elimination rather than the initial C-H cleavage, with variations in selectivity depending on the specific PAH structure.
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Multiscale structure of LaAlO from single-crystal X-ray diffraction.

Acta Crystallogr B Struct Sci Cryst Eng Mater

August 2024

Department of Physics, Institute of Pure and Applied Sciences and Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan.

A domain-resolved synchrotron single-crystal X-ray diffraction study of a LaAlO pseudo-merohedral twin crystal was successfully carried out in combination with powder diffraction data from the same sample. Multiscale structure information ranging from micro- to nano- to atomic scale was determined from one single crystal. There is almost no change of domain ratios at temperatures of less than 400 K indicating no movement of the domain wall.

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Visible-Light-Driven Hydrogen Release from Dye-Sensitized Hydrogen Boride Nanosheets.

ACS Appl Mater Interfaces

July 2024

Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Tokyo, Meguro-ku 152-8552, Japan.

Article Synopsis
  • Hydrogen boride (HB) nanosheets are considered lightweight and safe hydrogen carriers due to their high hydrogen density (8.5 wt %) and ability to release hydrogen when exposed to light.* -
  • The study introduces dye-modified HB nanosheets that can generate hydrogen using visible light (over 470 nm), eliminating the need for heat, by allowing electron transfer from excited dye molecules.* -
  • While the hydrogen production decreases over time due to dye oxidation, enhancing the process with agents like iodine ions and formic acid can sustain hydrogen generation from these nanosheets for longer periods.*
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Ball-milled MoS with graphene shows enhanced catalytic activity for hydrogen evolution reaction.

Sci Technol Adv Mater

May 2024

Department of Materials Science, Institute of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Japan.

The hydrogen evolution reaction (HER) is an important phenomenon in water splitting. Consequently, the development of an active, earth-abundant, and inexpensive HER catalyst is highly desired. MoS has drawn considerable interest as an HER catalyst because it is composed of non-precious metal and exhibits high catalytic activity in the nanosheet form.

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Article Synopsis
  • * Results showed that tin perovskite layers exhibited significant downward band bending, which negatively impacts hole selectivity and surface passivation.
  • * However, the addition of Sn powder to the precursor solution improved the situation by preventing downward band bending and promoting upward band bending, enhancing hole selectivity and overall efficiency of tin perovskite solar cells.
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A detailed understanding of the ultrafast dynamics of halogen-bonded materials is desired for designing supramolecular materials and tuning various electronic properties by external stimuli. Here, a prototypical halogen-bonded multifunctional material containing spin crossover (SCO) cations and paramagnetic radical anions is studied as a model system of photo-switchable SCO hybrid systems using ultrafast electron diffraction and two complementary optical spectroscopic techniques. Our results reveal a sequential dynamics from SCO to radical dimer softening, uncovering a key transient intermediate state.

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Photoinduced dynamics during electronic transfer from narrow to wide bandgap layers in one-dimensional heterostructured materials.

Nat Commun

May 2024

Institute of Pure and Applied Science and Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba, Tsukuba, 305-8573, Japan.

Electron transfer is a fundamental energy conversion process widely present in synthetic, industrial, and natural systems. Understanding the electron transfer process is important to exploit the uniqueness of the low-dimensional van der Waals (vdW) heterostructures because interlayer electron transfer produces the function of this class of material. Here, we show the occurrence of an electron transfer process in one-dimensional layer-stacking of carbon nanotubes (CNTs) and boron nitride nanotubes (BNNTs).

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Fusion Growth and Extraordinary Distortion of Ultrasmall Metal Oxide Nanoparticles.

J Am Chem Soc

June 2024

WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan.

Ultrasmall metal oxide nanoparticles (<5 nm) potentially have new properties, different from conventional nanoparticles. The precise size control of ultrasmall nanoparticles remains difficult for metal oxide. In this study, the size of CeO nanoparticles was precisely controlled (1.

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Synthesis and Optical Properties of Binaphthyl Derivatives with Comprehensive Introduction of Phenylethynyl Groups.

Chem Asian J

August 2024

Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, 606-8522, Japan.

In this study, compounds with phenylethynyl (PE) groups introduced at all of the possible positions of the methylene-bridged structure of the 1,1'-bi-2-naphthol backbone (3-PE to 8-PE) were synthesized. Compounds with four or six phenylethynyl groups (3,6-PE, 4,6-PE, 5,6-PE, 6,7-PE, and 3,4,6-PE) were also synthesized. The key reaction for the synthesis of these compounds was the Sonogashira reaction using halogen scaffolds.

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