Country：Japan

Country：Japan

Country：Japan

Country：Japan

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

DOI： 10.1007/s10971-022-05897-8

Other URL： https://link.springer.com/article/10.1007/s10971-022-05897-8/fulltext.html

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

The degree of pore filling is an important parameter for defining guest@MOF properties in applications including electronics, optics, and gas separation. However, the interplay of key aspects of host–guest interactions, such as a quantitative description of the guest alignment or the structural integrity of the host as function of pore filling are yet to be determined. Polarisation-dependent infrared spectroscopy in attenuated total reflection configuration combined with gas sorption allowed to simultaneously study the orientation of the guest molecule and structural changes of the MOF framework during the pore filling process. Thereby we found, that initially randomly oriented guest molecules align with increasing pore filling during adsorption from the gas phase. At the same time, the framework itself undergoes a reversible, guest molecule-dependent rotation of the aromatic linker and a linker detachment process, which induce defects.

DOI： 10.1002/anie.202201725

Other URL： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/anie.202201725

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

DOI： 10.1246/cl.220108

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

DOI： 10.1002/ange.202201725

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Chiral inorganic materials have attracted increasing attention in the fields such as catalysis, electronics, photonics, and sensing. A new class of functional materials with chirality is extensively explored. Herein, we demonstrate the synthesis of nanometric nickel layered hydroxide salt (Ni-LHS) modified with chiral amino acids, (D- or L-) phenylalanine (PHE). An alkalization reaction in a starting mixture of nickel-phenylalanine aqua complexes was induced by using propylene oxide, leading to intercalate and adsorb phenylalanine on the surface and into the interlayers of Ni-LHS in an in-situ manner. The chiral molecules also act as surface modifier to inhibit the extensive crystal growth and aggregation, to form Ni-LHS with a diameter of 2–3 nm in a state of stablly-suspended in a solvent. It was also found that Ni-LHS exhibit induced circular dichroism (ICD) in the spectral range of d-d transitions of Ni(II) metal centres. The layered nanomaterials with chiroptical response demonstrated here is a promising option as an advanced adsorbent for detection of molecules. [Figure not available: see fulltext.]

DOI： 10.1007/s10971-022-05766-4

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Processing oriented metal–organic frameworks (MOFs) as thin films is a key challenge for their application to device fabrication. However, typical fabrication methods cannot generate precisely oriented crystals on commercially relevant scales (i.e., cm2). This limits access to applications that require anisotropic functional properties (e.g., separation, optics, and electronics). Currently, highly oriented copper-based MOFs are synthesized via the addition of the organic MOF component to an ethanolic solution of manually aligned Cu(OH)2 nanobelt films. In this work, the optimization of a semi-automatic method for the fabrication of precisely oriented MOF films that affords a 100% yield of high quality ceramic films at the centimeter scale is reported. This improved fabrication protocol will facilitate the progress of heteroepitaxially grown MOFs for molecular separators and micro-opto-electronic devices.

DOI： 10.1002/admi.202101039

Other URL： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/admi.202101039

Kind of work：Joint Work  

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Kind of work：Joint Work  

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Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Molecular structures of siloxane materials should be highly controlled for achieving advanced functionalities. However, it is still difficult to precisely control the structure of siloxane materials by the sol–gel processing. In the present study, we focused on the silanol groups in the intermediate oligomers and resultant siloxane materials as a key structural unit for controlling the molecular structure. Thermal stability and chemical reactivity of silanol groups were found to be highly dependent on the steric effects of the surrounding side chains and siloxane skeletons. The present work suggests that controlling the steric effects around silanol groups in the intermediate oligomers allows modulating the crosslink density of siloxane skeletons. The selective molecular modification tunes the structure and chemical properties of the resultant siloxane materials. [Figure not available: see fulltext.]

DOI： 10.1007/s10971-020-05448-z

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Oriented film and pattern of TCNQ@Cu₃(BTC)₂(HKUST-1) fabricated <italic>via</italic> epitaxial growth exhibit anisotropic electrical properties toward MOF-based (flexible) thin-film smart device applications, such as transistors and thermoelectric thin films.

DOI： 10.1039/d1ta02968a

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

<p>Polarization-dependent infrared spectroscopy of oriented metal organic framework films fills the information gap left by diffraction methods and gives access to the orientation of the aromatic linker and initial orientation of ultra-thin films.</p>

DOI： 10.1039/d1sc02370e

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Multilayered metal-organic frameworks (MOF) thin films, called MOF-on-MOF thin films, generate integrated and multiple functionalities toward high-performance sensing, electrochemical, and optical devices. Although epitaxy at the MOF/MOF interfaces in these multilayered MOF films plays a crucial role for high functionalities, the effect of structural consistency at a molecular scale at the epitaxial interface on the quality of the films (e.g., crystallite size and degree of orientation of MOF-on-MOF thin films) has not been explored. Here, we report the factors governing such physical parameters by revealing a relationship between lattice mismatch ratios and orientations of MOF-on-MOF thin films with epitaxial interfaces (referred as to "e-MoM thin films"). Highly oriented e-MoM thin films were successfully obtained by considering not only lattice mismatch ratios but also stacking order depending on the lattice parameters of MOF components. Because of the chemical and structural tunability of e-MoM materials, the present finding will offer insight into fabricating e-MoM thin films for designing future MOF-based devices.

DOI： 10.1021/acsanm.0c03462

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

DOI： 10.1016/j.clay.2021.106006

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Kind of work：Single Work  

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Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. A design of atomic and oligomer level structure in organic-inorganic hybrid materials is highly important for various applications. Nonaqueous acid-base reaction allows us to prepare silicophosphates with controlled inorganic networks (-(O-P-O-Si)n) at atomic level because phosphorous and silicon-based precursors can react directly, resulting in an alternating copolymer network. Organic functionalization in those materials has been realized so far by using organic-modified phosphorous acid and/or organo-chlorosilane as precursors. In the present study, silicophosphate oligomers exhibiting inorganic-organic hybrid chains of (-(O-P-O-Si-R-Si)n) (R: bridging organic functional groups), are prepared from phosphoric acid and organo-bridged bis(chlorosilane). The 1, 2-bis(chlorodimethylsilyl)ethane ((C2H4)(Me2SiCl)2) and 1, 4-bis(chlorodimethylsilyl)benzene ((C6H4)(Me2SiCl)2) were used as organo-bridged bis(chlorosilane). Different types of silicophosphate oligomers with different network structures and terminal groups (P-OH and/or Si-Cl) were prepared by changing the reaction temperature and molar ratio of precursors. The formation of low molecular weight oligomers of ring and cage morphologies (ring tetramer, cage pentamer, and ring hexamer) is suggested in the product prepared from phosphoric acid and (C6H4)(Me2SiCl)2 molecule at 150 °C. Those silicophosphate hybrid oligomers are expected to be used as building blocks of hybrid materials with well-defined network structures for desired functionalities.

DOI： 10.3390/molecules25010127

PubMed

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

DOI： 10.2109/jcersj2.20105

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Imparting an enhanced CO2 reduction selectivity to ZnGa2O4 photocatalysts has been demonstrated by controlled crystallization from interdispersed nanoparticles of zinc and gallium hydroxides. The hydroxide precursor in which Zn(ii) and Ga(iii) are homogeneously interdispersed was prepared through an epoxide-driven sol-gel reaction. ZnGa2O4 obtained by a heat-treatment exhibits a higher surface basicity and an enhanced affinity for CO2 molecules than previously-reported standard ZnGa2O4. The enhanced affinity for CO2 molecules of the resultant ZnGa2O4 leads to highly-selective CO evolution in CO2 photo-reduction with H2O reductants. The present scheme is promising to achieve desirable surface chemistry on metal oxide photocatalysts.

DOI： 10.1039/d0ra00710b

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Thin films of metal-organic frameworks (MOFs) have attracted huge interests for various applications (e.g., sensing, catalysts and opto-electronics) due to their large porosity and tunable chemical property. Controlling the position and orientation of MOF crystals on device-scale substrates (over the centimeter scale) is required for the practical use of these sophisticated applications. Cu(OH)2 is a good precursor of the Cu-based MOF thin film due to their high reactivity with organic linkers, which allows for the growth of MOFs under mild conditions. In addition, lattice matching allows for the epitaxial growth of MOFs on Cu(OH)2. This article describes our recent progress on the fabrication of MOF thin films grown on assemblies of nanostructured Cu(OH)2. The approach enables us to control both position and orientation of MOF crystals on a substrate. The present approach for oriented MOF thin film growth is expanded for the oriented MOF-on-MOF thin films where different types of MOF layers possess epitaxial interfaces. A unique anisotropic plasmon resonance is found in the oriented MOFon- MOF films accommodating Ag nanoparticles. These materials demonstrated here are considered as good candidates for functional porous coatings for solid catalysts, bio-sensors, electrical/optical devises and others.

DOI： 10.2497/jjspm.67.132

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

© 2020 The Royal Society of Chemistry. Controlling the direction of molecular-scale pores enables the accommodation of guest molecular-scale species with alignment in the desired direction, allowing for the development of high-performance mechanical, thermal, electronic, photonic and biomedical organic devices (host-guest approach). Regularly ordered 1D nanochannels of metal-organic frameworks (MOFs) have been demonstrated as superior hosts for aligning functional molecules and polymers. However, controlling the orientation of MOF films with 1D nanochannels at commercially relevant scales remains a significant challenge. Here, we report the fabrication of macroscopically oriented films of Cu-based pillar-layered MOFs having regularly ordered 1D nanochannels. The direction of 1D nanochannels is controllable by optimizing the crystal growth process; 1D nanochannels align either perpendicular or parallel to substrates, offering molecular-scale pore arrays for a macroscopic alignment of functional guest molecules in the desired direction. Due to the fundamental interest and widespread technological importance of controlling the alignment of functional molecules and polymers in a particular direction, orientation-controllable MOF films will open up the possibility of realising the potential of MOFs in advanced technologies.

DOI： 10.1039/d0sc02958k

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

© 2020 American Chemical Society. Enormous efforts have been devoted to the development of crystalline aerogels toward heterogeneous catalysis, energy storage, ion/molecular absorption, and luminescence. However, properties of aerogels are not fully exploited due to their low content of functional moieties embedded in their solid networks, low crystallinity, and limited chemical compositions. Herein, we develop a one-pot approach based on crystallization from amorphous metal hydroxides modified with a β-diketone ligand, toward crystalline transition-metal hydroxide aerogels. Synthesis of monolithic and crystalline aerogels of layered double hydroxide (LDH) was performed in a Ni-Al system starting from aqueous ethanol solutions of NiCl2·6H2O and AlCl3·6H2O with acetylacetone (acac) as an organic ligand. Propylene oxide (PO) as an alkalization reagent was added into precursory solutions to yield monolithic wet gels. The successive pH increase induces the formation of a three-dimensional (3-D) solid framework composed of amorphous Al(OH)3. Then, amphoteric Al(OH)3 undergoes crystallization into Ni-Al LDH via an acetylacetone-driven dissolution-crystallization of metal hydroxides without destroying the preformed 3-D solid framework. The process allows us to obtain crystalline aerogel monoliths with high porosity and high transparency after supercritical CO2 drying of wet gels. The present scheme can be expected to synthesize functionalized aerogel composed of crystalline transition-metal oxide/hydroxide nanobuilding blocks (NBBs).

DOI： 10.1021/acs.langmuir.0c01292

PubMed

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

© The Royal Society of Chemistry. A novel approach for thermo-responsive wettability has been accomplished by surface roughness change induced by thermal expansion of paraffin coated on titanate nanostructures. The surface exhibits thermo-responsive and reversible wettability change in a hydrophobic regime; the surface shows superhydrophobicity with contact angles of ∼157° below 50 °C and ∼118° above 50 °C due to a decrease of surface roughness caused by thermally-expanded paraffin at higher temperatures. Reversible wettability change of ∼40° of a contact angle allows for fast and multi-directional droplet transport. The present approach affords a versatile selection of materials and wide variety of contact angles, promoting both scientific advancement and technology innovation in the field of smart surfaces. This journal is

DOI： 10.1039/d0ra05471b

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

DOI： 10.1002/ange.201904691

Kind of work：Joint Work  

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

DOI： 10.1002/anie.201904691

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

DOI： 10.1002/ange.201901707

Kind of work：Joint Work  

Kind of work：Joint Work  

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Deformation of the mesostructures in surfactant/silica hybrid films and mesoporous silica films prepared on bulky elastomeric substrates is investigated by compressing the substrates along an in-plane direction of the films. The mesostructure in the surfactant/silica hybrid film consists of organized micelles and a silica matrix. The micelles are removed in the mesoporous silica films to leave mesopores. A grazing-incidence small-angle X-ray scattering investigation reveals that the mesostructures with C2mm symmetry anisotropically change under a compressive strain of 6% in both films; shrinkage of the lattice parameters is along the direction of compression and extension in the normal direction. Deformation is reversible below a strain as high as 6%. Anisotropic deformation of the mesostructures results in an anisotropic change of the refractive indices normal and parallel to the direction of the compression. Compression of the surfactant/silica hybrid film induces a decrease of the refractive index parallel to the surface and an increase normal to the surface on the order of 10-3, while an opposite result is observed for the mesoporous silica film. The present finding gives us fundamental insight into the development of adaptive optical components for sensing, attenuation, switching, modulation, shutters, filters, and others in soft-material-based devices.

DOI： 10.1021/acsanm.9b00269

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

DOI： 10.2109/jcersj2.19089

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

The precise alignment of multiple layers of metal–organic framework (MOF) thin films, or MOF-on-MOF films, over macroscopic length scales is presented. The MOF-on-MOF films are fabricated by epitaxially matching the interface. The first MOF layer (Cu2(BPDC)2, BPDC=biphenyl-4,4′-dicarboxylate) is grown on an oriented Cu(OH)2 film by a “one-pot” approach. Aligned second (Cu2(BDC)2, BDC=benzene 1,4-dicarboxylate, or Cu2(BPYDC)2, BPYDC=2,2′-bipyridine-5,5′-dicarboxylate) MOF layers can be deposited using liquid-phase epitaxy. The co-orientation of the MOF films is confirmed by X-ray diffraction. Importantly, our strategy allows for the synthesis of aligned MOF films, for example, Cu2(BPYDC)2, that cannot be grown on a Cu(OH)2 surface. We show that aligned MOF films furnished with Ag nanoparticles show a unique anisotropic plasmon resonance. Our MOF-on-MOF approach expands the chemistry of heteroepitaxially oriented MOF films and provides a new toolbox for multifunctional porous coatings.

DOI： 10.1002/anie.201901707

PubMed

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