Publications by authors named "Kazuya Kubo"

Stable radicals have attracted increasing attention in recent years because of their unique electronic and optical characteristics. Aminoxyl radicals are one of the most widely studied stable radicals to date, but their applications in opto-functional materials have yet to be explored in detail. Our group previously reported the boron complexes of aminoxyl radicals exhibit near-infrared (NIR) absorption.

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Article Synopsis
  • Foot and ankle impairments are common in rheumatoid arthritis (RA) patients, often causing skin issues like calluses and ingrown toenails, prompting a study on expert foot care's effectiveness.
  • The study included 31 RA patients receiving foot care, with their progress tracked using a foot evaluation survey at three different points: baseline, 1.3 months, and 3.6 months later.
  • Results showed significant improvements in pain relief and general health, but no noticeable changes in physical functioning, social interactions, or footwear concerns, highlighting the need for clinicians to recognize the limitations of foot care in RA management.
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Methods relying on the use of solid solutions can be used to produce solid materials having finely controlled physical properties. In the current investigation, we utilized this protocol to prepare solid solutions derived from two different Werner complexes in order to assess the effects of component ratios on acetone vapor adsorption properties. For this purpose, microcrystalline solid solutions with the basic elemental composition α-[Cu(PF6)2(py)4]x[Cu(CF3SO3)2(py)4]1-x (x = 0.

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We report the synthesis, structural characterisation, and adsorption properties of a three-dimensional metal-organic framework [Zn(pydcao)(DMF)] (H2-pydcao = 3,5-pyridinedicarboxylic acid N-oxide) that has an unprecedented [Zn2(N-oxide)2] secondary building unit.

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We report the synthesis of five novel crystals [(4-BrAni+)(DB[18]crown-6)]2[SMo12O402-]·2CH3CN (1), [(4-BrAni+)(B[18]crown-6)]2[SMo12O402-]·CH3CN (2), [(4-BrAni+)(B[18]crown-6)]3[PMo12O402-]·2CH3CN (3), [(3-AP+)3(B[18]crown-6)2][PMo12O403-] (4) and [NBu4+][(3-AP2+)(DB[30]crown-10)][PMo12O403-]·CH3CN (5) (4-BrAni+ = 4-bromoanilinium; B[18]crown-6 = benzo[18]-crown-6; DB[18]crown-6 = dibenzo[18]-crown-6; DB[30]crown-10 = dibenzo[30]-crown-10; 3-AP+ = 3-aminopyridinium; 3-AP2+ = 3-ammoniumpyridinium; NBu4+ = tetrabutylammonium). In order to construct non-centrosymmetric crystals, the five crystals were designed using a method to gradually introduce asymmetry into the building units. Crystal 1 was constructed with a symmetric supramolecular cation (SPC) [(4-BrAni+)(DB[18]crown-6)], resulting in a P21/n space group.

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The Mott transition-a metal-insulator transition caused by repulsive Coulomb interactions between electrons-is a central issue in condensed matter physics because it is the mother earth of various attractive phenomena. Outstanding examples are high- (critical temperature) cuprates and manganites exhibiting colossal magnetoresistance. Furthermore, spin liquid states, which are quantum-fluctuation-driven disordered ground states in antiferromagnets, have recently been found in magnetic systems very near the Mott transition.

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A two-dimensional (2D) layered Mg(II) coordination polymer (CP) with a high tolerance for H2 O was designed, synthesised, and crystallographically characterised. The synthesis was achieved by the introduction of a flexible 2D layered structure composed of Mg(II) ions and isonicotinate N-oxide ligands. Owing to its high H2 O tolerance, the obtained 2D layered structure has the flexibility to repeatedly adsorb a large amount of H2 O associated with interlayer expansion and enable the removal of H2 O from a H2 O/2-propanol mixed vapour.

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The development of highly efficient CO separation materials is very important for environmental preservation and energy conservation. Crystalline porous coordination polymers (PCPs)/metal-organic frameworks are one of a number of promising types of porous materials for CO separation because of their controllable pore size, shape and surface function. Simultaneously, the unique structural flexibility of PCPs affords both high CO selectivity and inexpensive regeneration.

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Invited for this month's cover is the group of Prof. Shin-ichiro Noro from Hokkaido University, Japan. The cover picture shows a copper(II) porous coordination polymer that can adsorb CO over CH at high selectivity under CO /CH mixed gas conditions, even with the coexistence of water.

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The design of inexpensive and less toxic porous coordination polymers (PCPs) that show selective adsorption or high adsorption capacity is a critical issue in research on applicable porous materials. Although use of Group II magnesium(II) and calcium(II) ions as building blocks could provide cheaper materials and lead to enhanced biocompatibility, examples of magnesium(II) and calcium(II) PCPs are extremely limited compared with commonly used transition metal ones, because neutral bridging ligands have not been available for magnesium(II) and calcium(II) ions. Here we report a rationally designed neutral and charge-polarized bridging ligand as a new partner for magnesium(II) and calcium(II) ions.

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We evaluated the skeletal muscle loss in hemodialysis (HD) patients by bioelectrical impedance analysis (BIA) and handgrip strength test. Thirty-four HD patients and 16 healthy subjects (control group) were measured for skeletal muscle mass normalized as the skeletal muscle mass index (SMI), calculated as skeletal muscle mass (kg)/height (m)(2) using a tetrapolar bioelectrical impedance plethysmograph. Handgrip strength test was also performed using a hand dynamometer in both groups.

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Purpose: To determine whether vigorous and moderate physical activity volumes are associated with skeletal muscle loss and chronic kidney disease-mineral and bone disorder (CKD-MBD) in hemodialysis (HD) patients.

Methods: Skeletal muscle index (SMI) was measured using a bioelectrical impedance plethysmograph, and grip strength using a hand dynamometer, in 32 HD patients and 16 healthy controls. In HD patients, bone density was measured using digital image processing, and serum bone metabolism markers were measured as surrogate markers for CKD-MBD.

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Ferroelectricity is essential to many forms of current technology, ranging from sensors and actuators to optical or memory devices. In this circumstance, organic ferroelectrics are of particular importance because of their potential application in tomorrow's organic devices, and several pure organic ferroelectrics have been recently developed. However, some problems, such as current leakage and/or low working frequencies, make their application prospects especially for ferroelectric memory (FeRAM) not clear.

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We report the syntheses and crystal structures of novel porous assemblies of coordination complexes (PACs) with/without guest molecules, α-[Cu(A)₂(py)₄] (α-PAC-2-A (A = PF₆, BF₄, CF₃SO₃, and CH₃SO₃); py = pyridine), γ-{[Cu(PF₆)₂(py)₄]·2guest} (γ-PAC-2-PF₆ ⊃ 2guest (guest = acetone and py)), γ-{[Cu(BF₄)₂(py)₄]·2acetone} (γ-PAC-2-BF₄ ⊃ 2acetone), and β-{[Cu(CH₃SO₃)₂(py)₄]·2.67H₂O} (β-PAC-2-CH₃SO₃ ⊃ 2.67H₂O).

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The use of divalent Cu(II) ions and an anion-mixing method led to the rational construction of a porous coordination polymer bridged by weak Lewis-base inorganic CF3SO3(-) monoanions.

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Porous coordination polymer (PCP) polymorphs with the formula [Cu(CF3SO3)2(bpp)2]n [1 and 2, where bpp = 1,3-bis(4-pyridyl)propane] have been synthesized and crystallographically characterized, and their distinguishable porous properties have been investigated. 1 was obtained by the removal of guest acetone molecules from one-dimensional PCP {[Cu(CF3SO3)(bpp)2]·CF3SO3·2acetone}n (1⊃2acetone), while 2 was derived from two-dimensional PCP {[Cu(CF3SO3)2(bpp)2]·H2O}n (2⊃H2O) by the loss of guest H2O molecules. The desolvated PCPs 1 and 2 with the same formula [Cu(CF3SO3)2(bpp)2] showed distinguishable structures, suggesting PCP polymorphs.

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Supramolecular cations formed by monoprotonated pyridazinium cations and cis-anti-cis-dicyclohexano[18]-crown-6 (DCH[18]-crown-6) or dibenzo[18]-crown-6 (DB[18]-crown-6) were introduced into [Ni(dmit)2]− salts (where dmit2− = 2-thione-1,3-dithiole-4,5-dithiolate). X-ray crystal structure analysis of (pyridazinium+)(DCH[18]-crown-6)[Ni(dmit)2]− (1) revealed a chair-type conformation of the DCH[18]-crown-6 moiety. A V-shaped conformation of the DB[18]-crown-6 moiety was observed in (pyridazinium+)(DB[18]-crown-6)2[Ni(dmit)2]−(H2O)2 (2).

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Two new isostructural molecular metals-(BDH-TTP)(6)[M(III)(C(5)O(5))(3)]·CH(2)Cl(2) (BDH-TTP = 2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene, where M = Fe (1) and Ga (2))-have been prepared and fully characterized. Compound 1 is a molecular conductor showing paramagnetic behavior, which is due to the presence of isolated [Fe(C(5)O(5))(3)](3-) complexes with high-spin S = (5)/(2) Fe(III) metal ions. The conductivity originates from the BDH-TTP organic donors arranged in a κ-type molecular packing.

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Supramolecular assemblies of anilinium (Ani(+)) and fluoroanilinium derivatives (FAni(+)) with [18]crown-6 were introduced into electrically conducting [Ni(dmit)(2)] crystals (dmit(2-) is 2-thioxo-1,3-dithiole-4,5-dithiolate). The crystal structures, electrical conductivities, and magnetic susceptibilities of four new crystals of (Ani(+))([18]crown-6)[Ni(dmit)(2)](3) (1), (o-FAni(+))([18]crown-6)[Ni(dmit)(2)](3) (2), (m-FAni(+))([18]crown-6)[Ni(dmit)(2)](3) (3), and (p-FAni(+))([18]crown-6)[Ni(dmit)(2)](3) (4) were examined from the viewpoint of dynamic supramolecular rotator structures within the crystals. The crystal structures, electrical conduction, and magnetic properties were classified into group-I (crystals 1 and 4) and group-II (crystals 2 and 3).

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Sandwich-type hydrogen-bonded supramolecular dications (DAAz(2+))([18]crown-6)(2) and (DAAz(2+))(dicyclohexane[18]crown-6)(2) (DAAz(2+) = 4,4'-(phenylazophenyl)diammonium) were introduced into [Ni(dmit)(2)](-) anions via a diffusion method to form novel single crystals (DAAz(2+))([18]crown-6)(2)[Ni(dmit)(2)](2) (1) and (DAAz(2+))(dicyclohexane[18]crown-6)(2)[Ni(dmit)(2)](2) (2), respectively, which were characterized based on their crystal structures and magnetic susceptibilities. The molecular assembly structures and its physical properties were expanded in the use of a three component molecular network system. The two ammonium groups (-NH(3)(+)) of the DAAz(2+) dication formed N-H(+)-O hydrogen-bonding interactions with the oxygen atoms of [18]crown-6 and dicyclohexane[18]crown-6.

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The electrochemical oxidation of an acetone solution containing [Mn(III) (5-MeOsaltmen)(H(2)O)](2)(PF(6))(2) (5-MeOsaltmen(2-) = N,N'-(1,1,2,2-tetramethylethylene)bis(5-methoxysalicylideneiminate)) and (NBu(4))[Ni(dmit)(2)] (dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate) afforded a hybrid material, [Mn(5-MeOsaltmen)(acetone)](2)[Ni(dmit)(2)](6) (1), in which [Mn(2)](2+) single-molecule magnets (SMMs) with an S(T) = 4 ground state and [Ni(dmit)(2)](n-) molecules in a charge-ordered state (n = 0 or 1) are assembled in a layer-by-layer structure. Compound 1 crystallizes in the triclinic space group P1 with an inversion center at the midpoint of the Mn···Mn dimer. The [Mn(2)](2+) unit has a typical nonplanar Mn(III) dimeric core and is structurally consistent with previously reported [Mn(2)] SMMs.

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Bis(2,3-pyrazinedithiolate)nickel complex Na[Ni(pdt)(2)]·2H(2)O formed one-dimensional stacks of the Ni(pdt)(2) units and showed strong antiferromagnetic interactions along the stacking direction. A first-order phase transition between the paramagnetic and diamagnetic states, which was driven by dimerization of the Ni(pdt)(2) units, accompanied by coordination bond formation, was observed.

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An alternating chain of a paddlewheel [Ru(2)(II,III)(O(2)CEt)(4)](+) (EtCO(2)(-) = propionate) complex and [Pt(mnt)(2)](-) (mnt(2-) = maleonitriledithiolate) has a ferrimagnetic spin arrangement of S = 3/2 and 1/2 local spins, respectively, as well as three-dimensional antiferromagnetic ordering with a canting mode at 8.6 K. This chain is stacked at the [Pt(mnt)(2)](-) units to form a slipped column in the vertical direction against the chain, which acts as a pathway for electrical conduction.

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The electronic properties of cation radical salts derived from organometallic mixed-ligand complexes [(ppy)Au(S-S)](ppy- = C-dehydro-2-phenylpyridine(-); S-S(2-) = dithiolene ligand) with Au(III)-C sigma-bond were investigated. A 2:1 salt complex [(ppy)Au(C8H4S8)]2[PF6] (C8H4S8(2-) = 2-((4,5-ethylenedithio)-1,3-dithiole-2-ylidene)-1,3-dithiole-4,5-dithiolate(2-)) exhibited semiconductive behavior under ambient pressure (rho rt = 2.6 Omega cm, Ea = 0.

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Trimetallic nickel dithiolene complexes with two tetrathiooxalate (tto) ligands were obtained by a reaction monitored by ESI-mass spectrometry followed by HPLC separation and were characterized by elemental or crystal structural analysis, MO calculations, and electrical conductivity measurements.

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