Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

A novel 2D Hofmann-type corrugated framework possessing Mn^II centres in the trigonal prismatic coordination geometry was derived by a combination of a quasi C_4v symmetric building unit [M^VN(CN)₄]²⁻ and a bidentate co-ligand dmbpy.

DOI： 10.1039/d3dt03914e

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Language：Others   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

Ion conductors comprising noncentrosymmetric frameworks have emerged as new functional materials. However, strongly correlated polarity functionality and ion transport have not been achieved. Herein, we report a ferroelectric proton conductor, K2MnN(CN)4·H2O (1·H2O), exhibiting the strong correlation between its polar skeleton and conductive ions that generate anomalous ferroelectricity via the proton-bias phenomenon. The application of an electric field of ±1 kV/cm (0.1 Hz) on 1·H2O at 298 K produced the ferroelectricity (polarization = 1.5 × 104 μC/cm2), which was enhanced by the ferroelectric-skeleton-trapped conductive protons. Furthermore, the strong polarity-proton transport coupling of 1·H2O induced a proton-rectification-like directional ion-conductive behavior that could be adjusted by the magnitude and direction of DC electric fields. Moreover, 1·H2O exhibited reversible polarity switching between the polar 1·H2O and its dehydrated form, 1, with a centrosymmetric structure comprising an order-disorder-type transition of the nitrido-bridged chains.

DOI： 10.1021/jacs.3c10841

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Dalton Transactions  

An efficient water-based purification strategy for metal-organic polyhedra (MOPs) using commercially available centrifugal ultrafiltration membranes was developed. Having a diameter above 3 nm, MOPs were almost fully retained by the filters, while free ligands and other impurities were washed away. MOP retention also enabled efficient counter-ion exchange. This method paves the way for the application of MOPs with biological systems.

DOI： 10.1039/d3dt01644g

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Publisher：Chemical Engineering Journal  

Despite their extreme toxicity for human and the environment, Cr(VI) species are widely used in multiple industrial processes. This brings the need of potent strategies for detection at trace level and for remediation of contaminated effluents. In this article, we present a novel composite containing Fe3O4 quantum dots (QDs) immobilized on polydopamine-functionalized graphene obtained by a simple and cost-effective hydrothermal process. The high affinity of the composite for Cr(VI) ions resulted in an efficient chemical coupling with the Fe3O4 QDs, offering a powerful platform for multimodal reactivity. First, the composite acted both as a fluorescence as well as nanozymatic sensing platform for detecting toxic Cr(VI) ions in aqueous solution with a limit of detection (LOD) of 18 nM and 47 nM, respectively. In addition, the composite proved to be a very efficient catalyst for the visible-light photoreduction of Cr(VI) to non-toxic Cr(III), showing an outstanding reduction by 99% in 20 min under natural sunlight and a good recyclability. This study is the first of its kind where metal oxide QDs anchored functionalized graphene has been explored both as fluorescence and colorimetric sensing platform for Cr(VI) detection as well as an efficient photocatalyst for reduction of toxic Cr(VI) to non-toxic Cr(III) ions.

DOI： 10.1016/j.cej.2023.145797

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Language：Others   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

The synthesis of Janus-type layers, which possess front and back sides that consist of different structures, remains a major challenge in the field of two-dimensional materials. In this study, two Janus-type layered coordination polymers, namely, CuII(NEtH2)(NMe2H·H2O)CuI(CN)3 (1) and CuII(NMe2H)(NMe2H·H2O)CuI(CN)3 (2), were synthesized via a simple one-pot procedure using copper(II) nitrate and sodium cyanido in mixed solutions of dimethylamine and ethylamine. Uniquely, 1 and 2 were composed of cyanido-bridged neutral layers and exhibited a CuICuII mixed-valent state. Meanwhile, using a solution of pure dimethylamine for the synthesis yielded the monovalent three-dimensional framework (NMe2H2)[CuI2(CN)3] (3). Results indicated that the simultaneous use of two mixed amines gave rise to the controlled reduction of CuII ions during the reaction. In addition, each face of the layers was coordinated by different amines on the axial positions of the CuII sites, resulting in anisotropic Janus layers. Furthermore, the thermal expansion behavior of 2 was investigated, demonstrating that the neutral [CuICuII(CN)3] layer was relatively rigid compared with the analogous anionic [CuI2(CN)3]− layer.

DOI： 10.1021/acs.inorgchem.3c03100

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DOI： 10.1002/anie.202307093

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Language：Others   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Mechanically interlocked architecture has inspired the fabrication of numerous molecular systems, such as rotaxanes, catenanes, molecular knots, and their polymeric analogues. However, to date, the studies in this field have only focused on the molecular-scale integrity and topology of its unique penetrating structure. Thus, the topological material design of such architectures has not been fully explored from the nano- to the macroscopic scale. Here, we propose a supramolecular interlocked system, MOFaxane, comprised of long chain molecules penetrating a microcrystal of metal–organic framework (MOF). In this study, we describe the synthesis of polypseudoMOFaxane that is one of the MOFaxane family. This has a polythreaded structure in which multiple polymer chains thread a single MOF microcrystal, forming a topological network in the bulk state. The topological crosslinking architecture is obtained by simply mixing polymers and MOFs, and displays characteristics distinct from those of conventional polyrotaxane materials, including suppression of unthreading reactions.

DOI： 10.1038/s41467-023-38835-5

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Other Link： https://www.nature.com/articles/s41467-023-38835-5

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Angewandte Chemie - International Edition  

We synthesized a (1-propylpyridinium)2[ReN(CN)4]-type organic–inorganic hybrid exhibiting water-vapor-induced drastic structural changes of the [ReN(CN)4]2− assemblies. Specifically, upon exposure to water vapor, dehydrated nitrido-bridged chains were converted to hydrated cyanido-bridged tetranuclear clusters via rearrangements of large molecular building units in the crystals. These switchable assembly forms display substantially different photo-physical properties, although in both cases the emission is caused by a metal-centered d–d transition. The nitrido-bridged chain exhibited a near-infrared (749 nm) emission, which blue-shifted as the temperature increased, while a visible (561 nm) emission and its red shift was demonstrated by the cyanido-bridged cluster.

DOI： 10.1002/anie.202306853

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Language：Others   Publishing type：Research paper (scientific journal)   Publisher：ACS Applied Nano Materials  

Accurate detection of trace analytes in biological samples is essential for medical diagnostics but usually requires complex and expensive instruments. Nanozymes, a series of nanosized systems with a catalytic activity mimicking that of peroxidase enzymes, offer a useful alternative for the design of sensing devices. In this article, we describe the synthesis of porous 3D nitrogen-doped crumpled graphene nanoparticles (CGNPs) and their use as a platform for the sensitive detection of dopamine (DA) in complex biological media such as blood serum. CGNPs were prepared by doping graphene oxide (GO) using ammonium hydroxide in a hydrothermal treatment. This procedure leads to the crumpling of GO sheets into porous sphere-like nanoparticles, with a diameter of 34 ± 10 nm. These nanoparticles with high surface area and improved electronic properties proved very active for the oxidation of the peroxidase substrate 3,3′,5,5′- tetramethylbenzidine (TMB). Our sensing device relied on the scavenging of hydroxyl radicals by DA, resulting in a turn-off effect for TMB oxidation. The system selectively detected DA with a limit of detection of 1.15 μM and a linearity range of 1 to 20 μM. The system also possessed good selectivity for DA in the presence of various interfering species, as well as in human blood serum.

DOI： 10.1021/acsanm.2c04582

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Language：Others   Publishing type：Research paper (scientific journal)   Publisher：Inorganic Chemistry  

The negative thermal expansion (NTE) of solid-state materials is of significance in various fields, but a very rare phenomenon. In this study, we carried out a meta-analysis for the anisotropic thermal expansion behavior of fifteen two-dimensional coordination polymers [M(salen)]2[M′(CN)4(solvent)] (M = Mn, Fe; M′ = MnN, ReN, Pt, Pt(I2)x; x = 0.18, 0.45, 0.85, 1.0; solvent = H2O, MeOH, MeCN) with a newly synthesized [Fe(salen)]2[MnN(CN)4(MeCN)]. Consequently, we successfully demonstrate the unusual NTE of the undulating coordination layers by an expansion deformation of the layers via strong interlayer interaction within the layer stacking. Notably, the layer volume of [Mn(salen)]2[ReN(CN)4] with its powder form decreases with a large NTE coefficient, αlayer-volume= -27 × 10-6K-1(100-500 K). This is a significantly large value despite the increase in layer thickness along the layer contraction based on the anisotropic transformation of undulating layers. Conversely, the analysis demonstrates that the chemical modification of the layers to enhance intralayer interaction rather than interlayer interaction switches a direction of the layer anisotropy, yielding positive thermal expansion materials with the coefficient of the layer volume reaching +92 × 10-6K-1

DOI： 10.1021/acs.inorgchem.2c03780

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Publishing type：Research paper (scientific journal)  

DOI： 10.26434/chemrxiv-2022-bhgjl

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Language：Others   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

Chemical responsivity in materials is essential to build systems with switchable functionalities. However, polarity-switchable materials are still rare because inducing a symmetry breaking of the crystal structure by adsorbing chemical species is difficult. In this study, we demonstrate that a molecular organic-inorganic hybrid crystal of (NEt4)2[MnN(CN)4] (1) undergoes polarity switching induced by water vapor and transforms into a rare example of proton-conducting second-harmonic-generation-active material. Centrosymmetric 1 transforms into noncentrosymmetric polar 1·3H2O and 1·MeOH by accommodating water and methanol molecules, respectively. However, only water vapor causes a spontaneous single-crystal-to-single-crystal transition. Moreover, 1·3H2O shows proton conduction with 2.3 × 10-6S/cm at 298 K and a relative humidity of 80%.

DOI： 10.1021/acs.inorgchem.2c02555

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The zero area TE of cyanide-bridged honeycomb layers occurs by complementary structural changes in the cation and anion counterparts.

DOI： 10.1039/d2ce00878e

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Layer flexibility in two-dimensional coordination polymers (2D-CPs) contributes to several functional materials as it results in anisotropic structural response to external stimuli. Chemical modification is a common technique for modifying layer structures. This study demonstrates that crystal morphology of a cyanide-bridged 2D-CP of type [Mn(salen)](2)[ReN(CN)(4)] (1) consisting of flexible undulating layers significantly impacts the layer configuration and assembly. Nanoplates of 1 showed an in-plane contraction of layers with a longer interlayer distance compared to the micrometer-sized rod-type particles. These effects by crystal morphology on the structure of the 2D-CP impacted the structural flexibility, resulting in dual-functional changes: the enhancement of the sensitivity of structural transformation to water adsorption and modification of anisotropic thermal expansion of 1. Moreover, the nanoplates incorporated new adsorption sites within the layers, resulting in the uptake of an additional water molecule compared to the micrometer-sized rods.

DOI： 10.1002/chem.202103404

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A luminescent two-dimensional coordination polymer of type [Cd(H2O)(EtOH)][ReN(CN)(4)(H2O)]center dot 2H(2)O (CdRe) incorporating "Janus-type" cyanido-bridged layers was synthesized. Within each layer of CdRe, the asymmetric [ReN(CN)(4)](2-) units are arranged so that all nitrides are oriented in the same direction. Moreover, Cd ions also have an asymmetric coordination structure, with ethanol being bound axially on the nitride side, and water on the opposite side. Layers are then stacked in a head-to-head manner, defining a succession of hydrophilic and hydrophobic interlayer domains. CdRe exhibits anisotropic thermal expansion including in-plane negative and out-of-plane positive thermal expansion behavior, and shows green emission (lambda(em) = 509 nm) originating from the metal-centered d-d transition of [ReN(CN)(4)](2-) units.

DOI： 10.1246/cl.210244

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<p>A series of crystalline porous materials was prepared by self-assembly of cationic metal–organic polyhedra with polyoxometalates.</p>

DOI： 10.1039/d1cc01185e

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A novel porous magnet consisting of cationic two-dimensional (2-D) layers extended by Fe-III-CN-Ni-II linkages and pseudo-pillar dianions was synthesized. The size-selective guest adsorption behaviour of water and methanol molecules originates from the narrow bottle-neck-type pores in the flexible pseudo-pillared-layer structure, which results in the switching of the magnetic phases from antiferromagnetic to ferromagnetic, involving significant changes in the interlayer distance.

DOI： 10.1039/d1cc01526e

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Anisotropic negative thermal expansion is a valuable property of solid-state materials, influencing their micromechanical and functional response. Two flexible two-dimensional (2D) cyanide-bridged coordination polymers (CPs) of type [Fe(salen)](2)[M(CN)(4)] (M=MnN (FeMnN) and Pt (FePt)) were synthesized. Their anisotropic negative thermal expansions was strongly linked to relaxations of node distortions in [Fe(salen)](+) units. Comparison with the [Mn(salen)](+) analogues indicated shorter bond lengths around iron(III), due to the different electronic states. These changes of node structures resulted in FeMnN and FePt exhibiting lower and higher degrees of anisotropic thermal expansion behavior, respectively, than their Mn analogues.

DOI： 10.1002/cnma.202100026

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The excited-state energy was tuned successfully by guest molecules in a cyanide-bridged luminescent coordination polymer (CP). Methanol or ethanol vapor reversibly and significantly changed the luminescent color of the CP between green and yellow (Δλem = 32 nm). These vapors did not significantly affect the environment around the luminophore in the ground state of the CP, whereas they modulated the excited states for the resulting bathochromic shift. The time-resolved photoluminescent spectra of the CP systems showed that solvent adsorption enhanced the energetic relaxation in the excited states. Furthermore, time-resolved infrared spectroscopy indicated that cyanide bridging in the CP became more flexible in the excited states than that in the ground state, highlighting the sensitivity of the excited states to external stimuli, such as the guest vapor. Overall, guest-tunable excited states will allow the more straightforward design of sensing materials by characterizing the transient excited states.

DOI： 10.1021/acs.inorgchem.1c00702

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Amorphous coordination polymers and metal-organic frameworks (MOFs) have attracted much attention owing to their various functionalities. Here, we demonstrate the tunable water adsorption behavior of a series of amorphous cyanide-bridged MOFs with different metals (M[Ni(CN)(4)]: MNi; M = Mn, Fe, and Co). All three compounds adsorb up to six water molecules at a certain vapor pressure (P-ads) and undergo conversion to crystalline Hofmann-type MOFs, M(H2O)(2)[Ni(CN)(4)]center dot 4H(2)O (MNi-H2O; M = Mn, Fe, and Co). The P-ads of MnNi, FeNi, and CoNi for water adsorption is P/P-0 = 0.4, 0.6, and 0.9, respectively. Although the amorphous nature of these materials prevented structural elucidation using X-ray crystallography techniques, the local-scale structure around the N-coordinated M(2+ )centers was analyzed using L-2,L-3-, K-edge X-ray absorption fine structure, and magnetic measurements. Upon hydration, the coordination geometry of these metal centers changed from tetrahedral to octahedral, resulting in significant reorganization of the MOF local structure. On the other hand, Ni[Ni(CN)(4)] (NiNi) containing square-planar Ni2+ centers did not undergo significant structural transformation and therefore abruptly adsorbed H2O in the low-pressure region. We could thus define how changes in the bond lengths and coordination geometry are related to the adsorption properties of amorphous MOF systems.

DOI： 10.1021/acs.inorgchem.0c03742

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Insertion of polymers into microporous metal-organic frameworks (MOFs) appeared recently as a powerful strategy to accomplish very difficult separations. However, the dynamics of their insertion remains to be fully unravelled. In this article, we describe the spontaneous insertion of poly(ethylene glycol) (PEG) into a flexible MOF. Thanks to the structural changes upon PEG insertion, in situ powder X-ray diffraction (PXRD) analysis could be performed. For PEGs with identical main chains, the insertion speed was strongly dependent on the nature of the terminus. Furthermore, a concentration dependence for terminal groups was observed, providing insight into the pore-opening mechanism, and suggesting a mildly cooperative terminus-first insertion. This establishes polymers as very valuable tools to study MOF dynamics, as their extended size allows domains with clearly different properties within the same macromolecule.

DOI： 10.1016/j.eurpolymj.2020.109855

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Unlike commonly used molecular recognition techniques, recognition of polymer structures requires an additional aspect of extremely high recognition ability, by which marginal structural differences can be identified in a large polymer chain. Herein we show that metal-organic frameworks (MOFs) can recognize polymer terminal structures, thus enabling the first reported chromatographic separation of polymers. End-functionalized polyethylene glycols (PEGs) are selectively inserted into the MOF channel, the insertion kinetics being dependent on the projection size of the PEG terminus. This size-selective insertion mechanism facilitates precise discrimination of end-functionalized PEGs using liquid chromatography (LC). An MOF-packed column thus provides an efficient and easily accessible method for the separation of such end-functionalized polymers using conventional LC systems.

DOI： 10.1021/jacs.9b13568

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The preparation of metal-organic structures with a controlled degree of disorder is currently one of the most promising fields of materials science. Here, we describe the effect of guest polymer chains on the transformation of a metal-organic framework (MOF). Heating a pillared MOF at a controlled temperature resulted in the exclusive removal of the pillar ligands, while the connectivity of the metal-organic square-grid layers was maintained. In the absence of a polymer, 2D-layers rearranged to form a new crystalline phase. In contrast, the presence of a polymer in the MOF inhibited totally the recrystallization, leading to a turbostratic phase with layers threaded and maintained apart by the polymer chains. This work demonstrates a new synthetic approach toward the preparation of anisotropic metal-organic materials with controlled disorder. It also reveals how guests can dramatically modify the conversion of host MOFs, even though no chemical reaction occurs between them.

DOI： 10.1021/jacs.9b07563

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Preparation of composites by inclusion of polymers inside metal-organic frameworks (MOFs) is a very powerful strategy to prepare innovative functional materials. MOF's nanosized pores disrupt polymer chains natural coiling and constrain them in an extended conformation, bringing new properties. At the single nanochannel scale, polymerization reactions are significantly modified due to confinement, and control over the primary structure (sequence, tacticity or branching) can be achieved. Because of confinement and chain extension, physical and chemical properties can also be significantly improved compared to the bulk state. Inclusion is also useful to control organization at a higher scale, for instance for precise polymer positioning or by acting as scaffold for an accessible microporous polymer network. Furthermore, the MOF ordering can be maintained in pure polymer systems even after removal of the host.

DOI： 10.1002/ijch.201800074

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Separation of high-molecular-weight polymers differing just by one monomeric unit remains a challenging task. Here, we describe a protocol using metal-organic frameworks (MOFs) for the efficient separation and purification of mixtures of polymers that differ only by their terminal groups. In this process, polymer chains are inserted by threading one of their extremities through a series of MOF nanowindows. Selected termini can be adjusted by tuning the MOF structure, and the insertion methodology. Accordingly, MOFs with permanently opened pores allow for the complete separation of poly(ethylene glycol) (PEG) based on steric hindrance of the terminal groups. Excellent separation is achieved, even for high molecular weights (20 kDa). Furthermore, the dynamic character of a flexible MOF is used to separate PEG mixtures with very similar terminal moieties, such as OH, OMe, and OEt, as the slight difference of polarity in these groups significantly changes the pore opening kinetics.

DOI： 10.1038/s41467-018-06099-z

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To achieve effective long-term disinfection of the root canals, we synthesized core-shell silver nanoparticles (AgNPs@SiO2) and used them to develop two irrigation solutions containing sodium phytate (SP) and ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'-tetraacetic acid (EGTA), respectively. Ex vivo studies with instrumented root canals revealed that the developed irrigation solutions can effectively remove the smear layer from the dentinal surfaces. Further in vitro experiments with single- and multispecies biofilms demonstrated for the first time that AgNPs@SiO2-based irrigation solutions possess excellent antimicrobial activities for at least 7 days, whereas the bare AgNPs lose the activity almost immediately and do not show any antibacterial activity after 2 days. The long-term antimicrobial activity exhibited by AgNPs@SiO2 solutions can be attributed to the sustainable availability of soluble silver, even after 7 days. Both solutions showed lower cytotoxicity toward human gingival fibroblasts compared to the conventionally used solution (3&#37; NaOCl and 17&#37; EDTA). Irrigation solutions containing AgNP@SiO2 may therefore be highly promising for applications needing a long-term antimicrobial effect.

DOI： 10.1021/acsami.7b13929

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The properties of polymeric materials can be amplified by macromolecular alignment. The highly ordered chain alignment of unsubstituted polythiophene, an unprocessable polymer, has been achieved using a porous coordination polymer (PCP) as a template. Due to the extended conjugation system, the obtained anisotropic polymer particles exhibit higher conductivity than that of polythiophene prepared by solution polymerization.

DOI： 10.1039/c7py00309a

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The development Of highly porous metal organic frameworks (MOFs) is greatly sought after, due to their wide range of applications. As an alternative to the,development of new structures, we propose to obtain new stable configurations for flexible MOFs by insertion of polymeric guests. The guests prevent the otherwise spontaneous closing of the host frameworks and result in stable opened forms. Introduced at a fraction of the maximal capacity, polymer chains cause an opening of the occupied nanochannels, and because of the MOF reticular stiffness, this opening is propagated to the neighboring nanochannels that become accessible,for adsorption. Composites were obtained by in situ,polymerization of vinyl monomers in the: nanochannels of an otherwise nonporous MOP, resulting in homogeneously loaded materials with a significant increase of porosity (S-BET m(2)/g);:in addition, by limiting the accessible configurations for the framework and forbidding the forbidding of a reactive intermediate, the polymeric guest prevented the thermal degradation of the host MOP even at very low loading (as low as. 3 wt &#37;) and increased it's stability domain by more than 200 degrees C.

DOI： 10.1021/jacs.7b02402

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The melting behavior of a coordination polymer (CP) crystal was utilized to achieve enhanced and optically switchable proton conductivity in the solid state. The strong acid molecules (triflic acid) were doped in one-dimensional (1D) CP, [Zn(HPO4)(H2PO4)(2)](ImH(2))(2) (ImH(2) = monoprotonated imidazole) in the melt state, and overall enhancement in the proton conductivity was obtained. The enhanced proton conductivity is assigned to increased number of mobile protons and defects created by acid doping. Optical control over proton conductivity in the CP is achieved by doping of the photo acid molecule pyranine into the melted CP. The pyranine reversibly generates the mobile acidic protons and local defects in the glassy state of CP resulting in the bulk switchable conductivity mediated by light irradiation. Utilization of CP crystal in liquid state enables to be a novel route to incorporate functional molecules and defects, and it provides a tool to control the bulk properties of the CP material.

DOI： 10.1002/anie.201700962

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The uptake of molecular guests, a hallmark of the supramolecular chemistry of cages and containers, has yet to be documented for soluble assemblies of metal nanoparticles. Here we demonstrate that gold nanoparticle-based supraspheres serve as a host for the hydrophobic uptake, transport and subsequent release of over two million organic guests, exceeding by five orders of magnitude the capacities of individual supramolecular cages or containers and rivalling those of zeolites and metal-organic frameworks on a mass-per-volume basis. The supraspheres are prepared in water by adding hexanethiol to polyoxometalate-protected 4 nm gold nanoparticles. Each 200 nm assembly contains hydrophobic cavities between the estimated 27,400 gold building blocks that are connected to one another by nanometre-sized pores. This gives a percolated network that effectively absorbs large numbers of molecules from water, including 600,000, 2,100,000 and 2,600,000 molecules (35, 190 and 234 g l(-1)) of para-dichorobenzene, bisphenol A and trinitrotoluene, respectively.

DOI： 10.1038/NNANO.2016.233

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DOI： 10.1107/S2053273317085412

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A synthetic route is presented for the realization of ultrathin freestanding nanoparticle membranes that are built of gold nanoparticles protected with trimethoxysilane-bearing ligands. The mechanism relies on interfacial assembly in an oil-water mixture. Upon shaking, nanoparticles are transported to the liquid-liquid interface of the oil droplets and form a network through the formation of Si-O-Si bridges. Reticulation of the nanoparticles during the dynamic process of droplet coalescence allows the formation of ultrathin membranes of only a few nanoparticle layers in thickness and square centimeters in dimension. The membranes can be manipulated, such as locally perforated, without causing their collapse. Furthermore they can be transferred onto solid or holey substrates. The synthetic route is compatible with a coassembly of dopants. As an example, membranes were doped with single walled carbon nanotubes, which resulted in a sizable increase of their electric conductivity.

DOI： 10.1002/admi.201600191

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A series of conductive porous composites were obtained by the polymerization of 3,4-ethylenedioxythiophene (EDOT) in the cavities of MIL-101(Ci). By controlling the amount of EDOT loaded into the host framework, it was possible to modulate the conductivity as well as the porosity of the composite. This approach yields materials with a reasonable electronic conductivity (1.1 X 10(-3) S.cm(-1)) while maintaining high porosity (S-BET = 803 m(2)/g). This serves as a promising strategy for obtaining highly nanotextuted conductive polymers with very high accessibility for small gas molecules, which are beneficial to the fabrication of a chemiresistive sensor for the detection of NO2.

DOI： 10.1021/jacs.6b05552

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Silver nanoparticles constitute a very promising approach for the development of new antimicrobial systems. Nanoparticulate objects can bring significant improvements in the antibacterial activity of this element, through specific effect such as an adsorption at bacterial surfaces. However, the mechanism of action is essentially driven by the oxidative dissolution of the nanoparticles, as indicated by recent direct observations. The rote of Ag+ release in the action mechanism was also indirectly observed in numerous studies, and explains the sensitivity of the antimicrobial activity to the presence of some chemical species, notably halides and sulfides which form insoluble salts with Ag+. As such, surface properties of Ag nanoparticles have a crucial impact on their potency, as they influence both physical (aggregation, affinity for bacterial membrane, etc.) and chemical (dissolution, passivation, etc.) phenomena. Here, we review the main parameters that will affect the surface state of Ag NPs and their influence on antimicrobial efficacy. We also provide an analysis of several works on Ag NPs activity, observed through the scope of an oxidative Ag+ release. (C) 2015 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.nantod.2015.04.002

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Bioelectrodes were prepared by encapsulating bacteria in a silica hydrogel, in the pores of graphite felt, which acts as a conductive network in the material. We observed the conversion of glucose into metabolites that could diffuse into the mesopores of the silica network and be oxidised at the graphite surface.

DOI： 10.1039/c2tb00312k

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Mass transport properties of electrodes prepared from graphite felt, as such and after silicification, have been studied using cyclic voltammetry. Within the graphite felt, the mass transport of a probe changes with decreasing scan rate, from a radial diffusion around fibers to a regime that is analogous to "thin-layer" systems. Furthermore, unlike classical "thin-layer" systems, the volume comprised in the felt is macroscopic (resulting in high current densities), while the time required to consume all diffusive species remains in the 1 min range. Silicification of graphite felt does not impact on the mass transport of the negatively charged molecular probe Fe(CN)(6)(3-) but significantly slows mass transport of positively charged Ru(NH3)(6)(3+). In the latter case, a parallel decrease of peak current intensity reflects limited mobility of the probe due to its strong interaction with the surface of the pore walls. These data provide important information for the optimization of the working conditions of these electrodes for the design of biosensors and biofuel cells.

DOI： 10.1021/jp403990m

Language：English   Publishing type：Research paper (scientific journal)  

Silica gels doped with double-walled carbon nanotubes (DWCNTs) were prepared using an aqueous sol gel route in mild conditions (neutral pH, room temperature). The wet gels exhibited both ionic and electronic conduction. Electrochemical impedance spectroscopy was used to study these two different conduction pathways that prevail at different characteristic time scales. The ionic conduction in the silica network was found to be independent of the DWCNT-doping rate. The electronic conduction through the DWCNT network was found to occur above a critical concentration (0.175 wt &#37;) corresponding to nanotube percolation threshold. The highest content in DWCNTs (0.8 wt &#37;) exhibited a conductivity of 0.05 S/m. Furthermore, the DWCNTs network was found to evolve even after the macroscopic solidification of the gel, suggesting a reorganization of the DWCNTs at the molecular level. This phenomenon could be attributed to the polarization effect of the electrode and was confirmed by Raman spectroscopy studies. Such materials can be useful for the design of sensors incorporating electroactive chemical or biological species.

DOI： 10.1021/jp2115669

Language：English   Publishing type：Research paper (scientific journal)  

We have prepared isostructural aluminium and gallium phosphate chains by ionothermal reactions in 1-ethyl-3-methylimidazolium bromide and 1-ethylpyridinium bromide under a variety of conditions. The chains can be prepared as pure phases or along with three dimensional framework phases. The chains are favoured at shorter heating times and the crystallinity can be improved by addition of transition metal acetates and amines which are not included in the final structure. The chain can be prepared with or without the presence of hydrofluoric acid. (C) 2010 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jssc.2010.05.002

Language：English   Publishing type：Research paper (scientific journal)  

The synthesis on the gram scale and characterization of a series of flexible functionalized iron terephthalate MIL-53(Fe) type solids are reported. Chemical groups of various polarities, hydrophilicities, and acidities (-Cl, -Br, -CF3, -CH3, -NH2, -OH, -CO2H) were introduced through the aromatic linker, to systematically modify the pore surface. X-ray powder diffraction (XRPD), molecular simulations, thermogravimetric analyses, and in situ IR and Fe-57 Mossbauer spectrometries indicate some similarities with the pristine MIL-53(Fe) solid, with the adoption of the narrow pore form for all solids in both the hydrated and dry forms. Combined XRPD and computational structure determinations allow concluding that the geometry of the pore opening is predominantly correlated with the intraframework interactions rather than the steric hindrance of the substituent. Only (MIL-53(Fe)-(CF3)(2)) exhibits a nitrogen accessible porosity (S-BET approximate to 100 m(2) g(-1)). The adsorption of some liquids leads to pore openings showing some very specific behaviors depending on the guest-MIL-53(Fe) framework interactions, which can be related to the energy difference between the narrow and large pore forms evaluated by molecular simulation.

DOI： 10.1021/ja9092715

Language：English   Publishing type：Research paper (scientific journal)  

We have used in situ energy dispersive synchrotron X-ray diffraction to study the crystallization of aluminum phosphate frameworks under ionothermal conditions with conventional and microwave heating. The reaction is shown to follow slightly different routes depending on the type of heating used and a kinetic analysis shows that the rate constant is 10 times higher under microwave heating (1.4 compared to 0.14 min(-1)). The conventionally heated reaction is shown to proceed by a transformation of SIZ-3 to SIZ-4 via an intermediate, while the microwave-heated reaction forms SIZ-4 directly. The kinetic analysis is used to rationalize the differences in reaction rate and the findings are supported by SEM images of the crystal morphologies which result from the two heating methods.

DOI： 10.1021/jp907785t

Event date： 2024.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：西船橋   Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Mito   Country：Japan  

Event date： 2023.9

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：水戸   Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：水戸   Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Mito   Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Mito   Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Mito   Country：Japan  

Event date： 2023.9

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：Mito   Country：Japan  

Event date： 2023.9

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：Mito   Country：Japan  

Event date： 2023.9

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：Mito   Country：Japan  

Event date： 2023.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Mito   Country：Japan  

Event date： 2023.7

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：北九州   Country：Japan  

Event date： 2023.7

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：北九州   Country：Japan  

Event date： 2023.7

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2023.7

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2023.6

Language：English  

Country：Japan  

Event date： 2022.3

Language：English   Presentation type：Oral presentation (general)  

Venue：Online   Country：Japan  

Event date： 2022.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Other Link： https://confit.atlas.jp/guide/event/csj102nd/top

Event date： 2022.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Online   Country：Japan  

Other Link： https://confit.atlas.jp/guide/event/csj102nd/top

Event date： 2021.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Online   Country：Japan  

Other Link： http://www.sakutai.jp/conference_en/the-71st-conference-of-japan-society-of-coordination-chemistry

Event date： 2021.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Online   Country：India  

Other Link： http://www.epormat.com/