The development of new halogen-bridged Pd chain complexes with molecular precision offers a promising strategy to stabilize Pd(III) ions, which are being considered as future optical, magnetic, dielectric, and conducting materials. More recently, uncommon and rare electronic states of Pd(III) ions in halogen-bridged chain complexes have been reported. In these systems, four different designed strategies have been adopted to stabilize Pd(III) oxidation states to date. This review focuses on the new strategies for the realization of Pd(III) halogen-bridged metal complexes (MX-Chains) using (1) weak ligand field and (2) triple hydrogen bond approaches. The resulting MX-Chains show clear evidence of the Pd(III) averaged-valence (AV) state rather than the conventional Pd(II)/Pd(IV) mixed-valence (MV) state. The relationships between the molecular structures, electronic states, and properties of these MX-Chains strongly depend on the in-plane ligands, counteranions and their surrounding environments. Furthermore, Pd(III) states have been found in the MX-Chains even above room temperature. Understanding and controlling the Pd(III) states in halogen-bridged chain complexes is a critical issue for development of next-generation devices, such as molecular electrical nano-wires. Overall, this review establishes halogen-bridged Pd(III) complexes as highly effective solid-state materials and provides detailed insight into their structure–property relationships, laying the groundwork for future developments in this new class of advanced materials.

Developing highly efficient multifunctional electrocatalysts is crucial for future sustainable energy pursuits, but remains a great challenge. Herein, a facile synthetic strategy is used to confine atomically thin Pd-PdO nanodomains to amorphous Ru metallene oxide (RuO2). The as-synthesized electrocatalyst (Pd(2)RuOx-0.5 h) exhibits excellent catalytic activity toward the pH-universal hydrogen evolution reaction (eta(10) = 14 mV in 1 m KOH, eta(10) = 12 mV in 0.5 m H2SO4, and eta(10) = 22 mV in 1 m PBS), alkaline oxygen evolution reaction (eta(10) = 225 mV), and overall water splitting (E-10 = 1.49 V) with high mass activity and operational stability. Further reduction endows the material (Pd(2)RuOx-2 h) with a promising alkaline oxygen reduction activity, evidenced by high halfway potential, four-electron selectivity, and excellent poison tolerance. The enhanced catalytic activity is attributed to the rational integration of favorable nanostructures, including 1) the atomically thin nanosheet morphology, 2) the coexisting amorphous and defective crystalline phases, and 3) the multi-component heterostructural features. These structural factors effectively regulate the material's electronic configuration and the adsorption of intermediates at the active sites for favorable reaction energetics.

Polarized FT-IR spectra of the Pt–I semiconductive nanowire, [Pt(en)2I](Asp-C_n)₂·H₂O, revealed that the first Pt^III–Pt^III AV state for n ≥ 13.

<title>Abstract</title>Lithium-ion-encapsulated fullerenes (Li⁺@C₆₀) are 3D superatoms with rich oxidative states. Here we show a conductive and magnetically frustrated metal–fullerene-bonded framework {[Cu₄(Li@C₆₀)(L)(py)₄](NTf₂)(hexane)}_{<italic>n</italic>} (<bold>1</bold>) (<italic>L</italic> = 1,2,4,5-tetrakis(methanesulfonamido)benzene, py = pyridine, NTf₂⁻ = bis(trifluoromethane)sulfonamide anion) prepared from redox-active dinuclear metal complex Cu₂(L)(py)₄ and lithium-ion-encapsulated fullerene salt (Li⁺@C₆₀)(NTf₂⁻). Electron donor Cu₂(L)(py)₂ bonds to acceptor Li⁺@C₆₀ via eight Cu‒C bonds. Cu–C bond formation stems from spontaneous charge transfer (CT) between Cu₂(L)(py)₄ and (Li⁺@C₆₀)(NTf₂⁻) by removing the two-terminal py molecules, yielding triplet ground state [Cu₂(L)(py)₂]⁺(Li⁺@C₆₀^•−), evidenced by absorption and electron paramagnetic resonance (EPR) spectra, magnetic properties and quantum chemical calculations. Moreover, Li⁺@C₆₀^•− radicals (<italic>S</italic> = ½) and Cu²⁺ ions (<italic>S</italic> = ½) interact antiferromagnetically in triangular spin lattices in the absence of long-range magnetic ordering to 1.8 K. The low-temperature heat capacity indicated that compound <bold>1</bold> is a potential candidate for an <italic>S</italic> = ½ quantum spin liquid (QSL).

<title>Abstract</title>The creation of low-dimensional heterostructures for intelligent devices is a challenging research topic; however, macro- and atomic-scale connections in one-dimensional (1D) electronic systems have not been achieved yet. Herein, we synthesize a heterostructure comprising a 1D Mott insulator [Ni(chxn)₂Br]Br₂ (<bold>1</bold>; chxn = 1<italic>R</italic>-2<italic>R</italic>-diaminocyclohexane) and a 1D Peierls or charge-density-wave insulator [Pd(chxn)₂Br]Br₂ (<bold>2</bold>) using stepwise electrochemical growth. It can be considered as the first example of electrochemical liquid-phase epitaxy applied to molecular-based heterostructures with a macroscopic scale. Moreover, atomic-resolution scanning tunneling microscopy images reveal a modulation of the electronic state in the heterojunction region with a length of five metal atoms (~ 2.5 nm), that is a direct evidence for the atomic-scale connection of <bold>1</bold> and <bold>2</bold>. This is the first time that the heterojunction in the 1D chains has been shown and examined experimentally at macro- and atomic-scale. This study thus serves as proof of concept for heterojunctions in 1D electronic systems.

We demonstrate a measurement system for synchrotron-radiation-based Mössbauer absorption spectra with 161Dy using the 25.7 keV nuclear first excited state. Mössbauer spectra of DyF3, Dy metal and DyPc2 (Pc = phthalocyaninato) were obtained and the parameters for the hyperfine structure of 161Dy nuclei in them were evaluated to demonstrate the feasibility of this method. Isomer shifts showed that Dy atoms in all of them are in trivalent state although those in Dy metal was in the region of trivalent metal region. The magnetic hyperfine field of Dy metal of 569 ± 1 T agreed with the literature of the Mössbauer experiments. That of DyPc2 of 489 ± 1 T was reasonable because the ground state of DyPc2 were in the state of Jz = ±13/2. Considering the highly penetrative nature of the 25.7 keV incident radiation, it will be straightforward to apply this method for the study of materials under various conditions such as high pressure, high magnetic fields, and reactive atmospheres.

We report the water adsorption/desorption behavior and dynamic magnetic properties of the Pt-Cl chain complex [{[Pt(en)2 ][PtCl2 (en)2 ]}3 ][{(MnCl5 )Cl3 }2 ] ⋅ 12H2 O (1). Upon heating 1 in a vacuum, we obtained the dehydrated form [{[Pt(en)2 ][PtCl2 (en)2 ]}3 ][{(MnCl5 )Cl3 }2 ] (1DH). The framework structures of 1 and 1DH are identical, and both complexes underwent slow magnetic relaxation. However, the magnetic relaxation times for 1DH were shorter than those for 1, meaning that the dynamic magnetic properties were controlled upon water vapor adsorption/desorption. From detailed analyses of the dynamic magnetic behavior, a phonon-bottleneck effect contributes to the magnetic relaxation processes. We discuss the mechanism for the changes in the magnetic relaxation processes upon dehydration in terms of the heat capacity and thermal conductivity.

プレプリント

Halogen-bridged linear chain metal complexes (MX-Chains) are fascinating compounds that have a quasi-one-dimensional (1D) electronic system. In this study, we synthesized the first Ni-based MX-Chain compound having hydroxy groups, i.e., [Ni(dabdOH)2Br]Br2·[Ni(dabdOHx)2Br]0.5·(2-PrOH)0.25·(MeOH)0.25(1·solvent, x = ∼0.6, dabdOH = (2S,3S)-2,3-diaminobutane-1,4-diol). Single-crystal X-ray diffraction revealed that the MX-Chains in 1·solvent formed sheets and single-chain structures in the superlattice. It suggested an MH-like state, whereas the polarized reflection and Raman spectra suggested a CDW-like state. Magnetic and electron spin resonance measurements revealed that both high-spin Ni(II) (∼15%) and low-spin Ni(III) (∼85%) sites are present in the chain structures, i.e., the metal sites show mixed valency. Therefore, we concluded that 1·solvent adopts an intermediate state between the MH and CDW states. Moreover, a single crystal of 1·solvent exhibited semiconductive characteristics along the chain direction. This finding represents a new structural and electronic state of 1D electronic systems as well as MX-Chains.

プレプリント

Lanthanide (Ln) compounds are common research targets in the field of magnetism and optics. Their properties arise from the electron localized in the f-orbital. Moreover, the effect of the covalency between lanthanide and ligands on magnetism attracted significant attention. We provided insight into the Gd–Pt bond (of the heterometallic Ln-Pt complexes: {[Pt(PhSAc)4]Ln[(PhSAc)4Pt]} NEt4·2DMF (Ln = Y(0), La(1), Gd(2); PhSAc = thiobenzoate, NEt4 = tetraethylammonium)); single-crystal polarized X-ray absorption near edge structure (XANES) reveal the electronic states around metal ion, where spectra of Gd-LIII edges show the Gd–Pt direction has the highest covalency (less ionic) around Gd ion in 2. In addition, calculating natural bonding (NBO) analysis, natural population analysis (NPA), LOL, and atoms in molecules (AIM), ab initio calculations reveal the role of metallic and organic ligands in the electronic and magnetic properties of Ln complexes. The slow magnetization relaxation of the Gd complex, which has not been reported previously in the Pt–Gd–Pt system, was observed up to 45K, the highest temperature reported to date among isolated Gd-complexes.

The dynamical magnetic behavior of metal complexes correlates with their phonon modes, which depend on solid polymorphs. However, no systematic study has revealed the correlation between solid phases and spin-lattice...

We report here a structurally perfect kagomé lattice {[Cu<underline>3</underline>(bpy)<underline>6</underline>](SiF<underline>6</underline>)<underline>3</underline>(melamine)<underline>8</underline>}<underline>n</underline> (<bold>1</bold>), where bpy is 4,4′-bipyridine and [SiF<underline>6</underline>]^2‒ is hexafluorosilicate anion. In comparison to general 1D linear, 2D layered and 3D cubic...

Low-voltage operation, high durability, and long memory time are demanded for electrochromic (EC) display device applications. Metallo-supramolecular polymers (MSPs), composed of a metal ion and ditopic ligand, are one of the recently developed EC materials, and the ligand modification is expected to tune the redox potential of MSP. In order to lower the redox potential of MSP, tetrakis(N-methylbenzimidazolyl)bipyridine (L-Bip) was designed as an electronically rich ligand. Ru-based MSP (polyRu-LBip) was successfully synthesized by 1:1 complexation of RuCl2(DMSO)(4) with LBip. The molecular weight (M-w) was high (8.8 x 10(6) Da) enough to provide a simple H-1 NMR spectrum, of which the proton peaks could be assigned by the comparison with the spectrum of the corresponding mono-Ru complex. The redox potential (E-1/2) between Ru(II/III) was 0.51 V versus Ag/Ag+, which was much lower than the redox potential of previously reported Ru-based MSP with bis(terpyridyl)benzene (0.95 V vs Ag/Ag+). The polymer film exhibited reversible, distinct color changes between violet and light green-yellow upon applying very low potentials of 0 and 0.6 V vs Ag/Ag+, respectively. The appearance and disappearance of the metal-to-ligand charge transfer absorption by the electrochemical redox between Ru(II/III) were confirmed using in situ spectro-electrochemical measurement. A solid-state EC device with polyRu-L-Bip was revealed to have large optical contrast (Delta T 54%), fast response time (1.37 s for bleaching and 0.67 s for coloration), remarkable coloration efficiency (571 cm(2)/C), and high durability for the repeated color changes more than 20,000 cycles. The device also showed a long optical memory time of up to 19 h to maintain 40% to the initial contrast under the open circuit conditions. It is considered that the stabilization of the Ru(III) state by L-Bip suppressed the self-coloring to Ru(II) inside the device.

For the development of durable electrochromic (EC) materials with wide absorption, large optical contrast, and high coloration efficiency, a three-dimensionally hyperbranched Fe(II)-based metallo-supramolecular polymer (polyFe3-D) was one-step synthesized by the complexation of an Fe(II) salt and an asymmetrical ditopic ligand (L) containing terpyridine (tpy) and phenanthroline (phen) moieties, according to the formation of a 1:2 complex of Fe(II) and tpys (Fe-tpys) and a 1:3 complex of Fe(II) and phens (Fe-phens). The formation of Fe-tpys and Fe-phens was confirmed by the appearance of two metal-to-ligand charge transfer (MLCT) absorptions in the visible area during the titration experiment. The molecular weight (M-w) of polyFe-3D was determined to 3.96 x 10(5) Da by a size-exclusion chromatography-viscometry measurement. PolyFe-3D with the two different Fe(II) complexes (Fe-typs and Fe-phens) exhibited a pair of redox waves for Fe(II/III) (E-1/2 = 0.74 V vs Ag/Ag+) reversibly in the cyclic voltammograms. The linear relationship between the peak current and the root of the scan rate during redox suggested a diffusion-controlled redox reaction. The spin-coated polymer film showed reversible EC changes between magenta and pale green, caused by the redox of Fe(II/III). A wide visible region from 430 to 640 nm was covered with the two MLCT absorptions of the Fe-tpys and Fe-phens moieties. The broad MLCT absorption disappeared upon applying 1.2 V vs Ag/Ag+ and reappeared at 0 V vs Ag/Ag+. The EC changes were revealed to have both a large transmittance change (Delta T) with 70% at 573 nm and a very high coloration efficiency (eta) with 689 cm(2)/C. The coloration efficiency exceeded those of the reported linear (one-dimensional), two-dimensional nanosheeted, and three-dimensional hyperbranched Fe(II)-based metallo-supramolecular polymers. A polyFe-3D film showed high durability for the EC changes of more than 1000 cycles. A solid-state simple device fabricated using polyFe-3D exhibited reversible EC changes of more than 1000 cycles without degradation.

Single-molecule magnets exhibit magnetic bistabililties at the molecular level, making them promising for molecule-based spintronics due to high magnetic densities. The incorporation of SMM behavior and electrical conductivity in one compound is rare because these two physical properties often do not operate in the same temperature range, which further hinders their use in practical applications. Here we present an organic-inorganic molecular hybrid, β″-(BEDO-TTF)3[Co(pdms)2]·(MeCN)(H2O)2 (BO3) (BEDO-TTF = bis(ethylenedioxy)tetrathiafulvalene and H2pdms = 1,2-bis(methanesulfonamido)benzene), which manifests both metallic conduction (electrical conductivity up to 1000 S cm-1 at 12 K under 2.0 gigapascal pressure) and SMM behavior in the temperature range 12-26 K for the first time.

<p>A thermally stable and highly electrically conductive Pd(<sc>iii</sc>) 1D complex [Pd(dabdOH)₂Cl]Cl₂ was newly synthesized.</p>

Dual-redox metallo-supramolecular polymers with a zigzag structure (polyFe-N and polyRu-N) were successfully synthesized by 1:1 complexation of a redox-active Fe(II) or Ru(II) ion and 4,4-bis(2,2:6,2-terpyridinyl)phenyl-triphenylamine (L-TPA) as a redox-active ligand. The polymers had high solubility in methanol, and the polymer solutions showed dark brown (polyFe-N) or orange-red (polyRu-N) coloration. UV-vis spectra of the polymers displayed a strong metal-to-ligand charge transfer (MLCT) absorption in the visible region. Cyclic voltammograms of the polymer films exhibited two pairs of reversible redox waves. The first redox at similar to 0.5 V versus Ag/Ag+ was assigned to the redox in the triphenylamine (TPA) moiety of L-TPA, and the second redox at 0.8 V versus Ag/Ag+ (polyFe-N) or 0.9 V versus Ag/Ag+ (polyRu-N) was given to the redox of Fe(II)/(III) or Ru(II)/(III), respectively. Upon applying a positive potential of more than 0.5 V versus Ag/Ag+ to the polymer films, a new absorption at similar to 820 nm in the near-infrared (NIR) region appeared with wide tailing to the longer wavelength. It is considered that the new absorption in the NIR region is caused by the polaron band of the oxidized ligand in the polymers. When the applied potential was increased to 1.0 V versus Ag/Ag+ (polyFe-N) or 1.1 V versus Ag/Ag+ (polyRu-N), the maximum wavelength of the new absorption in the NIR region shifted to 885-900 nm and the absorbance was further enhanced with disappearance of the MLCT absorption. Eventually, the original colors of the polymers were faint to light green. This visible-to-NIR electrochromism was reversible, and maximum optical contrast (Delta T) reached 52% in the visible region and 80% in the NIR region. A prototype solid-state device with the polymer was fabricated for practical utilization, exhibiting excellent cycle stability of >4000 cycles with maintaining high optical contrast from the visible-to-NIR range.

This article was published with erroneous affiliation number information regarding author Makoto Seto. Please find in this document the correct affiliation citation for author Makoto Seto that should be regarded as the final version by the reader. This article is part of the Topical Collection on Proceedings of the International Conference on the Applications of the Mössbauer Effect (ICAME2019), 1-6 September 2019, Dalian, China.

Highly dense hexagonal Fe(II)-based coordination nanosheets (CONASHs) were designed by dual-branching, at the metal-coordination moieties and the tritopic ligands, which successfully obtained a liquid/liquid interface by the complexation of Fe(II) ions and the tritopic bidentate ligands. The 1:1 complexation was confirmed by titration. The obtained Fe(II)-based nanosheets were fully characterized by small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). A monolayer of the sheets was obtained, employing the Langmuir-Blodgett (LB) method, and the determined thickness was similar to 2.5 nm. The polymer nanosheets exhibited red-to-colorless electrochromism because the electrochemical redox transformation between Fe(II) and Fe (III) ions controlled the appearance/disappearance of the metal (ion)-to-ligand charge-transfer (MLCT) absorption. The poor pi-conjugation in the tritopic ligands contributed to the highly colorless electrochromic state. A solid-state device, with the robust polymer film, exhibited excellent electrochromic (EC) properties, with high optical contrast (Delta T > 65%) and high durability after repeated color changes for >15 000 cycles, upon applying low-operating voltages (+1.5/0 V).

We synthesized Fe(II)-based metallo-supramolecular polymers with bisterpyridines bearing ethynylene, phenylene, and durene as spacer (polyFeL1-3) and investigated the effect of the spacer modification on the electrochromic properties. We revealed the redox potential and MLCT absorption of polymers were greatly influenced by the spacer alteration. PolyFeL1-3 exhibited different colors; blue, bluish purple, and purple, respectively. Blue- and purple-colored electrochromic devices were successfully fabricated using polyFeL1 and polyFeL3. The electrochromic color changes were observed upon applying +3V for bleaching or -3V for coloring.

The use of metallo-supramolecular polymer (MSP) as a thin-film-based redox supercapacitor electrode material is reported for the first time. Fe(II)- and Ru(II)-based MSPs (polyFe and polyRu, respectively) were synthesized by complexation of appropriate metal salts with 4',4 ''-(1,4-phenylene)bis-2,2':6',2 ''-terpyridine, and thin films of these polymers were prepared by spray coating onto an indium tin oxide glass substrate. A study of the energy storage performances of the polyFe and polyRu films in a nonaqueous electrolyte system revealed volumetric capacitances of similar to 62.6 +/- 3 F/cm(3) for polyFe and 98.5 +/- 7 F/cm(3) for polyRu at a current density of 2 A/cm(3). To improve the energy storage performance over a wider potential range, asymmetric supercapacitor (ASC) displays were fabricated with suitable combinations of the MSPs as cathodic materials and Prussian blue as the anodic counter material in a sandwich configuration with a transparent polymeric ion gel as the electrolyte. The fabricated ASCs showed a maximum volumetric energy density (similar to 10-18 mW h/cm(3)) that was higher than that of lithium thin-film batteries and a power density (7 W/cm(3)) comparable to that of conventional electrolyte capacitors, with superb cyclic stability for 10 000 cycles. To demonstrate the practical use of the MSP, the illumination of a light-emitting diode bulb was powered by a laboratory-made device. This work should inspire the development of high-performance thin-film flexible supercapacitors based on MSPs as active cathodic materials.

Four color electrochromism (yellow, magenta, blue, and navy) has been achieved in Cr(iii)-based metallo-supramolecular polymers (polyCr), which were synthesized by 1 : 1 complexation of Cr ions and 1,4-di[[2,2 ':6 ',2 ''-terpyridin]-4 '-yl]benzene (L). The polymer structure was determined by X-ray absorption fine structure (XAFS) measurement and X-ray photoelectron spectroscopy (XPS). The molecular weight of polyCr was calculated as 3.2 x 10(7) Da using right angle light scattering (RALS). The EXAFS fitting indicated that the bond distances of Cr-N are 2.020 angstrom and 2.208 angstrom. A film of polyCr shows multi-color electrochromism (EC) or absorption: a sharp peak at 380 nm at 0 V vs. Ag/Ag+ (yellow), a sharp peak at 510 nm and a broad peak at 800 nm at -0.6 V vs. Ag/Ag+ (magenta), a broad peak at 610 nm and between 700-900 nm at -1.2 V vs. Ag/Ag+ (blue), a broad peak between 450-900 nm at -1.8 V vs. Ag/Ag+ (navy). The transmittances change (Delta T), the switching times for coloring and bleaching (T-c, T-b) and the coloration efficiency (eta(c), eta(b)): [Delta T, (T-c, T-b), (eta(c), eta(b))] were [39.2%, (5.56 s, 1.39 s), (169 cm(2) C-1, 230 cm(2) C-1)] at 510 nm between -0.6 and 0.2 V vs. Ag/Ag+, [67.0%, (6.93 s, 2.52 s), (138 cm(2) C-1, 172 cm(2) C-1)] at 610 nm between -1.2 and 0.2 V vs. Ag/Ag+, [86.1%, (6.80 s, 3.03 s), (167 cm(2) C-1, 134 cm(2) C-1)] at 780 nm between -1.8 and 0.2 V vs. Ag/Ag+, respectively, during the cycles. The durability experiment indicates that polyCr shows an EC property for at least 100 cycles.

This is a report to reveal the role of alkali metal ions on proton transfer in metallo-supramolecular polymers (MSPs). We successfully synthesized europium(III)-based MSPs with different counter cations (Li+, Na+, and K+) (polyEu-M+, M = Li, Na, and K, respectively) via 1:1 complexation of Eu(III) salt and tetracarboxylic acid-substituted bisterpyridine in the presence of metal hydroxide (MOH, M = Li, Na, and K). We found that the proton conductivity was dramatically changed by the countercation species of the polymer. Among the three polymers, polyEu-Li+ showed the highest proton conductivity (1.54 x 10(-2) S cm(-1)) at 95% relative humidity (RH) and 75 degrees C and also exhibited the lowest activation energy 0.14 eV at 95% RH. PolyEu-Li+ presented high water uptake (14.58), which was measured by the mass change (%) with respective reference mass, compared with polyEu-Na+ (13.08) and polyEu-K+ (11.50) at 95% RH. The results indicate that effective proton channels enabled by water molecules were formed in the presence of Li+.

A novel terpyridine-based bimetallic metallo-supramolecular polymer (polyFeOs) containing alternately complexed Fe(II) and Os(II) ions is synthesized. For precise synthesis of the polymer, a new three-step synthetic pathway is developed to obtain a high yield (%) of product in each step. The first step is the synthesis of dibromo terpyridine-Os(II) complex in 87% yield, the second step is the synthesis of bisterpyridine ligand containing Os(II) (OsL1) in 74% yield, and the last step is the synthesis of polyFeOs in 90% yield. The polyFeOs exhibits high thermal stability with two degradation temperatures at around 390 and 690 degrees C, which indicate thermal evaporation of the counter anions (Cl- and BF4-) and degradation of the coordination bonds, respectively. The combination of two different metal ions in polyFeOs results in an enlarged optical window (lambda = 315-675 nm) and two highly stable reversible redox states, which can be of huge interest for potential optical, electro-optical, and electrochemical applications.

<p>In this study, the electronic states of Os-based metallo-supramolecular polymers (<bold>poly(OsL)2+</bold>) during electrochromism were tracked by <italic>in situ</italic> X-ray absorption fine structure (XAFS), infrared (IR), and impedance spectroscopies.</p>

<p>A metallic single-molecule magnet was synthesised demonstrating simultaneous metallic conduction and excellent SMM properties at the same temperature range for the first time, with potential applications in molecule-based quantum spintronics.</p>

<p>A flexible coordination polymer with naphthalenediimide core exhibited the reversible desorption-adsorption of solvent molecules and the enhancement of electrical conductivity (~ 10^–7 S cm^–1) by chemical reduction using hydrazine.</p>

accepted

Accepted

BEST OF INTERNATIONAL DISPLAY WORKSHOPS 2018

A solid-state electrochromic (EC) device with high thermal durability was successfully fabricated by the combination of Fe(II)-based metallo-supramolecular polymer (polyFe) as a cathodically coloring EC layer, a poly (methyl methacrylate)-based solid-state electrolyte layer, and Prussian blue (PB) as an anodically coloring EC layer between two indium tin oxide (ITO)-coated glass conducting substrates. Spray coating technique was used to make polyFe film on ITO-glass. Counter materials were investigated to improve the long-term durability and performance of solid state devices. The polyFe layer thickness was optimized at 240 +/- 50 nm, resulting in better electrochromic performance of the fabricated device with transmittance change of similar to 54% and 95% cyclic stability after 1000 cycles with a short response time by applying voltages of +2.7 V and -1.3 V reversibly. Importantly, the thermal stability of the fabricated solid device was also explored, and we achieved maximum temperature stability at 100 degrees C with 50% retention of device properties in this study.

The coordination nanosheets (CONASHs) are emerging as a new class of functional two-dimensional materials, which are one of the most active research areas of chemistry and physics in this decade. Despite the success of various structural and functional CONASHs, the development of a new molecular structure to discover alluring functional CONASHs remains challenging. Herein, we report successful preparation of two novel CONASHs (NBP1 and NBP2) through coordination between one of the unexplored molecular frameworks of bis(2,2'-bipyridine)-based ligands (BP1 and BP2) and Fe2+ ions. Using a liquid-liquid interface as a platform, large-scale thin films of multilayer CONASHs have been prepared without any support, which can be deposited onto any desired substrate. Detailed characterization of the CONASHs using various microscopic and spectroscopic techniques reveals homogeneous and flat morphology of nanometer thickness with the quantitative formation of tris(2,2'-bipyridine)-Fe2+ complex motifs in the nanosheet frameworks. The color of the films has been tuned from blue to magenta by the suitable molecular design of the ligands. Owing to the insolubility of the CONASH films in any solvent and the presence of redox-active Fe2+, we explore the functionality of these nanostructured thin films deposited on indium tin oxide as electrochromic materials. The CONASHs exhibit color-to-colorless and color-to-color electrochromic transitions with attractive response times, switching stabilities, and coloration efficiencies. Finally, we demonstrate solid-state electrochromic devices of the CONASHs operated at a potential range of +2.5 to -2.5 V, which are electrochemically stable for several switching cycles, suggesting that these CONASHs are potential electrochromic materials for next-generation display applications.

We successfully observed the synchrotron-radiation-based Mossbauer absorption spectra with Gd-158 and Ru-99. Their nuclear resonant energies were 79.5 keV and 89.6 keV, respectively, and they are factually the highest energy which energy region synchrotron radiation covers with sufficient intensity as the incident X-rays for Mossbauer spectroscopy. Although the low recoilless fraction owing to these high resonant energy, Mossbauer energy spectra of GdPd3 to (Gd2O3)-Gd-158 and fcc-Ru nanoparticles to bulk hcp-Ru-99 metal were obtained with natural samples of the former compounds with sufficient amount, because of the high transparency of these high energy X-rays(to electronic scattering). In spite of large statistical errors, we can evaluate the hyperfine parameters when the spectrum includes simple 1-site profile. Ru-99 and Gd-158 SR-based Mossbauer absorption spectra of various complex materials including somewhat complex structures will be available with the improvements to the measurement system; More detector elements for larger solid angle subtended to the scatterer sample will yields more counting rates and improvement higher recoilless fraction by arranging more appropriate chemical specimen as the scatterer yields deeper absorption profile.

A Tb(III)-based coordination polymer (polyTb) was synthesized by complexation of Tb(NO3)(3)center dot(6H(2)O) and 4',4 ''''-[1,1'-biphenyl]-4,4'-diylbis[6,6 ''-bis(ethoxycarbonyl)2':6',2 ''-terpyridine](L). The polymer structure was determined by Job's plots, DFT calculation, and X-ray absorption fine structure (XAFS) measurement. Job's plots indicated that the mole ratio (Tb ion:L) is 1:1. The optimized model structures suggested a La model: the LaN6 center dot center dot center dot(O=C)(2) model. The bond distances of La-O and La-N are similar to 2.80 angstrom and 2.60 angstrom, respectively. The EXAFS fitting indicated that the bond distances of Tb-O and Tb-N are 2.65 angstrom and 2.95 angstrom, respectively. polyTb shows field-induced magnetic relaxation in the solid and solution state. The luminescence of polyTb, originating from an f-f transition, was observed (phi = 6.9%). polyTb formed a porous structure on a Si substrate, whereas a fibrous complex structure was formed on glass. polyTb chains are orientated on glass, which were determined by XRD.

Developing high proton conducting solid materials is significant in the field of fuel cells. A europium(III)based metallo-supramolecular polymer with uncoordinated carboxylic acids (PolyEu-H) was successfully synthesized by modifying the synthesis conditions. The proton conductivity was enhanced with increasing the relative humidity (RH) from 30 to 95% RH. PolyEu-H showed about 104 times higher proton conductivity than the polymer with coordinated carboxylic acids (PolyEu) and about 400 times higher than the polymer without carboxylic acids (PolyEu-2). The proton conductivity of PolyEu-H reached 4.45 x 10(-2) S cm(-1) at 95% RH and 25 degrees C and 5.6 x 10(-2) S cm(-1) at 75 degrees C. The activation energy, Ea was ultralow (0.04 eV), which indicates proton conduction based on the Grotthuss mechanism. The results indicate that efficient proton conduction occurs through proton channels formed by moisture in PolyEu-H.

As newly designed electrochromic devices (ECDs), we fabricated a multi-patterned display (MPD) and a tube-shaped display (TSD) with Fe(II)-based metallo-supramolecular polymer (polyFe) and/or Ru(II)-based polymer (polyRu). The MPD was fabricated by staking three independent ECDs. The device thickness was less than 5 mm using both-sides-coated ITO glasses. The MPD presented eight different images with high contrast and fast response. The bleaching and coloring times (T-b and T-c) were 1.7 and 2.0 s at 500 nm, in which the absorption attributed to polyRu appears, respectively, and 3.6 and 1.8 s at 600 nm, in which the absorption attributed to polyFe appears, respectively. The TSD was successfully fabricated using two flexible ITO-PET films and two tube-shaped glasses. The TSD also showed good electrochromic behavior (T-b: 22 s and T-c: 3.6 s). These results guarantee the achievement of the further application for new design of architecture or appliance.

A heterometallic Tb-Pt complex, [Tb2Pt3(SAc)(12)(H2O)(2)] (SAc = thioacetate), was synthesized. Dual emission was modulated by the presence of a heterometallic Tb-Pt bonding environment. The heterometallic Tb-Pt bond lowers the symmetry of the Tb ion and enhanced the emission efficiency. In addition, the Tb-Pt complex shows field-induced multiple magnetic relaxation pathways. Furthermore, it served as an antenna for the observed dual emission. In other words, the heterometallic Tb-Pt bond has a significant effect on the luminescence and magnetic properties of the complex.

Heterometallic Gd-Pt complexes ([Gd2Pt3(H2O)(2)(SAc)(12)] (SAc=thioacetate), [Y1.4Gd0.6Pt3(H2O)(2)(SAc)(12)], and [Gd2Pt3(H2O)(6)(SAc)(12)]7H(2)O have been synthesized. The crystal structures and DFT calculations indicated a Gd-Pt heretometallic bond. Single-crystal ESR spectra determined the direction of magnetic anisotropy as direction of the Gd-Pt bond. In other words, the Gd-Pt bond dictates the direction of magnetic anisotropy. The heterometallic Gd-Pt bond lowers the symmetry of the Gd ion, splitting the Kramers doublet in a dc field. Thus, we observed clear field-induced slow magnetic relaxation of [Y1.4Gd0.6Pt3(H2O)(2)(SAc)(12)] up to 36K. The relaxation process was determined to be a direct process.

The temperature dependence of the Peierls-Hubbard phase transition in [Pd(cptn)(2)Br]Br-2 (cptn: 1R,2R diaminocyclopentane) was directly observed using a low-temperature scanning tunneling microscope. A short ligand without alkyl chains was used to form a rigid crystal lattice to reduce the effect of structural changes in the crystal with temperature. The hysteresis in the temperature dependence of the ratio between the areas of the charge density wave (CDW) state produced by the Pd-II-Pd-IV mixed-valence state and the Mott-Hubbard (MH) state with a Pd-III-averaged valence state which is a characteristic of the first-order phase transition, was directly observed at the atomic scale. Pinning of the CDW phase by defects was observed below the critical temperature, suggesting the growth of the CDW phase with defects as nuclei. (C) 2016 The Japan Society of Applied Physics

A neutral mononuclear Fe-III complex [Fe-III(H-5-Br-thsa-Me)(5-Br-thsa-Me)]H2O (1; H-2-5-Br-thsa-Me=5-bromosalicylaldehyde methylthiosemicarbazone) was prepared that exhibited a three-step spin-crossover (SCO) with symmetry breaking and a 14K hysteresis loop owing to strong cooperativity. Two ordered intermediate states of 1 were observed, 4HS-2LS and 2HS-4LS, which exhibited reentrant phase-transition behavior. This study provides a new platform for examining multistability in SCO complexes.

We synthesized a bromo-bridged Pd complex, which underwent as lowering the temperature a charge-density-wave (CDW) to Mott-Hubbard (MH) phase transition, as confirmed by using X-ray diffraction analysis, ESR, FT-IR and Raman spectroscopies. The complex showed a phase-separation phenomenon with a striped pattern over a wide temperature range, and domain propagation was observed using an optical microscope. Moreover, we observed changes in the local electronic state accompanying the phase transition by using scanning tunneling microscopy (STM).

低次元有機伝導体は、電子格子相互作用とオンサイトクーロン反発が競合して起こる転移系としてパイエルス-ハバードモデルの典型的系として注目されている。この転移は化学的圧力や光照射などの様々な物理パラメータで引き起こされる。本研究では、温度変化に伴う局所的な転移の進行過程を温度可変高空間分解能STMにより可視化した。<br>

Theoretical calculations are typically utilized for examining intermetallic interactions. However, to validate theory, experimental confirmation of the existence of these interactions is necessary. We synthesized new heterometallic Ln–Pt complexes, NEt4{[Pt(PhSAc)4]Ln[(PhSAc)4Pt]}·2DMF (Ln: lanthanoid = Gd (1), Tb (2), Dy (3), PhSAc = benzothioacetate, NEt4 = tetraethylammonium), in which both diamagnetic Pt(II) ions interact with the central Ln(III) ion. Typically, these interactions are not detected, because the distance between Ln and Pt atoms (~3.6 Å) is much larger than the covalent radius (~3.3 Å) and ionic radius (~3.10 Å). Pt-LIII resonant inelastic X-ray scattering (RIXS) analysis was conducted to experimentally confirm the unique influence of the hidden Ln–Pt interaction on the luminescence of the Tb–Pt molecule, where the interaction induced emission properties in the Tb and Pt ions, with high quantum yield (59%). Quantum theory of atoms in molecules (QTAIM) analysis was also used to confirm the experimental results. RIXS analysis allowed the identification of several distinctive characteristics of the coordination environment, including the existence of heterometallic interactions, that affected the observed luminescence.

Single-molecule magnets exhibit magnetic bistabililties at the molecular level, making them promising for molecule-based spintronics due to high magnetic densities. The incorporation of SMM behavior and electrical conductivity in one compound is rare because these two physical properties often do not operate in the same temperature range, which further hinders their use in practical applications. Here we present an organic-inorganic molecular hybrid, β″-(BEDO-TTF)3[Co(pdms)2]·(MeCN)(H2O)2 (BO3) (BEDO-TTF = bis(ethylenedioxy)tetrathiafulvalene and H2pdms = 1,2-bis(methanesulfonamido)benzene), which manifests both metallic conduction (electrical conductivity up to 1000 S cm-1 at 12 K under 2.0 gigapascal pressure) and SMM behavior in the temperature range 12-26 K for the first time.

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The coordination nanosheets (CONASHs) are emerging as a new class of functional two-dimensional materials, which are one of the most active research areas of chemistry and physics in this decade. Despite the success of various structural and functional CONASHs, the development of a new molecular structure to discover alluring functional CONASHs remains challenging. Herein, we report successful preparation of two novel CONASHs (NBP1 and NBP2) through coordination between one of the unexplored molecular frameworks of bis(2,2'-bipyridine)-based ligands (BP1 and BP2) and Fe2+ ions. Using a liquid-liquid interface as a platform, large-scale thin films of multilayer CONASHs have been prepared without any support, which can be deposited onto any desired substrate. Detailed characterization of the CONASHs using various microscopic and spectroscopic techniques reveals homogeneous and flat morphology of nanometer thickness with the quantitative formation of tris(2,2'-bipyridine)-Fe2+ complex motifs in the nanosheet frameworks. The color of the films has been tuned from blue to magenta by the suitable molecular design of the ligands. Owing to the insolubility of the CONASH films in any solvent and the presence of redox-active Fe2+, we explore the functionality of these nanostructured thin films deposited on indium tin oxide as electrochromic materials. The CONASHs exhibit color-to-colorless and color-to-color electrochromic transitions with attractive response times, switching stabilities, and coloration efficiencies. Finally, we demonstrate solid-state electrochromic devices of the CONASHs operated at a potential range of +2.5 to -2.5 V, which are electrochemically stable for several switching cycles, suggesting that these CONASHs are potential electrochromic materials for next-generation display applications.

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