Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Abstract

The recovery of crude oil and volatile organic compounds (VOCs) spilt in the environment is an intractable problem for environmental scientists. In this paper, a new lipophilic polyelectrolyte gel as an absorbent for various volatile chemical compounds is demonstrated. It is prepared by radical copolymerization of an acrylate monomer with an ionic group, tetraalkylammonium tetraarylborate, octadecyl acrylate, and a crosslinker, dipropylene glycol diacrylate, in the presence of a radial initiator. Investigation of the swelling behavior for the mixtures of water or aqueous salts reveals that the gel shows similar swelling behavior to those for pure organic solvents. On the other hand, the swelling degree in THF‐water mixture is lower than that of pure THF, because THF and water are miscible to each other, and the presence of a small amount of water in THF reduces the compatibility of the gel and THF. The salting‐out effect can separate the THF‐water mixture to form a biphasic system and recover the high swelling ability of the gel. The swelling behavior in the mixture of water‐organic solvents systems provides a new insight for designing VOC and oil absorbents in various environmental conditions, especially in hydrosphere such as seas and lakes.

DOI： 10.1002/macp.202100505

Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/macp.202100505

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

DOI： 10.1021/jacs.1c11665

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

DOI： 10.1021/acs.cgd.1c00506

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

To date, proton-conducting organic crystalline materials based on crown ethers have rarely been investigated.

DOI： 10.1039/d1ma00411e

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

Porous nanoparticles with interfacial adhesiveness boost the selectivity of separation membranes to achieve size-selective nanofiltration.

DOI： 10.1039/d1ta06205k

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

<p>Supramolecular cations, consisting of ethylammonium derivatives (X–CH₂CH₂–NH₃⁺) complexed with [18]crown-6, were incorporated into [Ni(dmit)₂]⁻ crystals in order to promote molecular motion.</p>

DOI： 10.1039/d1ce00253h

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Crystals of (HDABCO(+))(9)(DABCO)[Ni(dmit)(2)](9)center dot 6CH(3)CN were shown to have a space group of R3, a hexapetal flower-like channel of [Ni(dmit)(2)] anions, and a one-dimensional hydrogen bonding chain composed of protonated DABCO and CH3CN molecules. The crystals display antiferromagnetic and ferromagnetic interactions within and between hexamers, respectively, whereas the flexible DABCO-CH3CN array shows dielectric relaxation.

DOI： 10.1039/d0dt03386c

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Multi-thermoresponsiveness which exhibits more than triple phase transitions has not been achieved yet. Current research studies have reported double thermoresponsive copolymers having two kinds of polymer chains. However, the molecular design strategy of triple thermoresponsiveness remains unclear. Herein, we report a triple thermoresponsive chiral homopolymer which exhibits UCST- LCST-UCST-type phase transitions. The polymer contains the alpha,alpha,alpha',alpha'-tetraaryl-2,2-disubstituted 1,3-dioxolane-4,5-dimethanol moiety in the side chains, where multiple supramolecular complexes between the host polymer and guest molecules are formed. The formations and dynamic changes in the multiple complexes of model compounds were monitored by H-1 NMR spectroscopy. We concluded that the key factor of the triple thermoresponsive behavior is the stoichiometric change in the multiple complexes. This work can extend the molecular design of the thermoresponsive polymer and lead to the next stage of functional polymer materials.

DOI： 10.1021/acsapm.0c00491

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

The structural change in the excited state evidently plays a crucial role in the quenching process of organic molecules exhibiting aggregation-induced emission (AIE, thus AIEgens) in the solution state. In this report, we synthesized a series of tetraphenylethylene (TPE) macrocycles having a covalent oligoethylene glycol (OEG) linkage between vicinal phenyl rings with various chain lengths and substituting positions. As a result, the obtained TPE macrocycles which are tightly fastened by short OEG chains showed strong emission even in the solution state. The tight fastener efficiently restricted the pi twist around the central C-C bond in TPE macrocycles, which was also supported by theoretical computations. These results provide very important information about the origin of the AIE properties of TPE derivatives, which will lead to the rational design of new AIEgens.

DOI： 10.1039/d0qo00839g

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Aggregation-induced emission (AIE) is a fascinating phenomenon because of the applications of luminescent materials in the aggregated state, which exploit the large structural changes of the molecules in the excited state. Recently, it was reported that triphenylphosphane derivatives show AIE behavior in which they undergo potentially large structural changes in the excited state. Inspired by this report, photoinduced pyramidal inversion behavior of phosphanes was investigated. In photochemical experiments, the prepared P-stereogenic phosphanes exhibited photoracemization in dilute solution, and a negative correlation was observed between the photoracemization and the AIE phenomenon. Theoretical computations revealed that the inversion barrier in the excited state was much smaller than that in the ground state. This is the first report on the photoinduced pyramidal inversion behavior of phosphanes, which will provide new and unexplored applications.

DOI： 10.1002/chem.202002358

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Aggregation-induced emission (AIE) is a fascinating phenomenon because of the applications of luminescent materials in the aggregated state, which exploit the large structural changes of the molecules in the excited state. Recently, it was reported that triphenylphosphane derivatives show AIE behavior in which they undergo potentially large structural changes in the excited state. Inspired by this report, photoinduced pyramidal inversion behavior of phosphanes was investigated. In photochemical experiments, the prepared P-stereogenic phosphanes exhibited photoracemization in dilute solution, and a negative correlation was observed between the photoracemization and the AIE phenomenon. Theoretical computations revealed that the inversion barrier in the excited state was much smaller than that in the ground state. This is the first report on the photoinduced pyramidal inversion behavior of phosphanes, which will provide new and unexplored applications.

DOI： 10.1002/chem.202000264

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Thermoresponsive polymers in water, for example, poly(N-isopropylacrylamide) (PNIPAM) are investigated extensively, due to a wide range of biomedical applications. However, the attempts to control thermoresponsiveness are still rare in less or nonpolar media. Herein, the three thermoresponsive homopolymers tethering an N-butylurea group in the side chain with a different polymer backbone are reported. They exhibit lower critical solution temperature (LCST)-type and upper critical solution temperature (UCST)-type thermoresponsiveness depending on association of the urea group in the polymer chain and hydrogen bonding small molecules (effectors) in ternary systems (polymer/effector/organic solvent). The difference of polymer backbone appears as their change of solvophobicity in organic solvents. Poly(methacrylate) backbone needs more amount of the effector in nonpolar organic solvents, and poly(vinyl ether) backbone needs more amount in polar organic solvents. However, the influence of polymer backbone is too little to change the phase transition behavior, and the thermoresponsiveness is dominated by association and dissociation of hydrogen bondings between polymers and effectors. The supramolecular design of the thermoresponsive polymers is strong and extensible for the design of their phase transitions.

DOI： 10.1002/macp.201900455

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

The controlled release of small molecules from carrier materials by manipulating the environmental conditions has potential for use in drug delivery. In the present study, we demonstrate the controlled release of a guest molecule (procainamide) from a metal-organic framework (MOF). The MOF is covered with a copolymer of N-isopropyl acrylamide (NIPAM) and acrylic acid (AA) by post-synthetic modification. The polymer exhibits a rapid and reversible coil-globule transition that is both pH- and thermoresponsive, thereby allowing the guest molecules to be released from the MOF in an "on-off" manner. At high pH (6.86) or low temperatures (<25 degrees C)-when the polymer adopts a coil conformation-the guest molecules are rapidly released from the MOF, whereas at low pH (4.01) or high temperatures (>40 degrees C)-when the polymer adopts a globule conformation-the release of the guest molecules is suppressed. The release can be halted by applying external stimuli even after starting the release. The MOF-derived controllable container introduced here will facilitate targeted drug delivery and controlled release of therapeutic agents.

DOI： 10.1039/c9ce01731c

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

In the present study, we designed tetrahedral tetraarylborate pentads which were synthesized by a typical click reaction, copper-catalyzed azide-alkyne cyclization. The synthesis of the borate pentads was confirmed by FT-IR and NMR spectroscopies, and NMR measurements indicated a rapid exchange of bound and unbound counter cations. The obtained borate pentads exhibited a representative behavior of weak electrolytes, and thus a decrease of their concentration caused a rapid increase of their molar conductivity, especially at the limit of dilution. Additionally, the observed association constant did not correspond to the theoretical association constant, probably because of the multivalent ionic dissociation dependent on the dielectric constant of the media.

DOI： 10.1039/c9nj01772k

Publishing type：Part of collection (book)  

DOI： 10.1016/B978-0-12-814681-1.00013-8

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Aggregation-induced emission (AIE) is a photoluminescence phenomenon in which an AIE luminogen (AIEgen) exhibits intense emission in the aggregated or solid state but only weak or no emission in the solution state. Understanding the mechanism of AIE requires consideration of excited state molecular geometry (for example, a pi twist). This Minireview examines the history of AIEgens with a focus on the representative AIEgen, tetraphenylethylene (TPE). The mechanisms of solution-state quenching are reviewed and the crucial role of excited-state molecular transformations for AIE is discussed. Finally, recent progress in understanding the relationship between excited state molecular transformations and AIE is overviewed for a range of different AIEgens.

DOI： 10.1002/anie.201814462

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

The A-A/B-B step-growth copolymerization between a monomer immobilized in the crystalline state and a monomer mobile in the solution state is demonstrated. One of the two monomers was immobilized as organic ligands of the metal-organic framework (MOF) and polymerized with the mobile guest monomer, resulting in the formation of linear polymers. The polymerization behavior was completely different from that of the solution polymerizations. In particular, the degrees of polymerization (DP) converged to a specific value depending on the MOF structures. The inevitable termination is caused not by imperfectness of the polymerization reaction, but by the selection of the two polymerization partners among the several adjacent immobilized monomers. This is fully supported by the Monte Carlo simulation on the basis of the polymerization mechanism. Precise immobilization of monomers in the supramolecular assemblies is a promising way for the controlled A-A/B-B step-growth polymerization.

DOI： 10.1002/anie.201901308

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

An octahedral metal-organic framework (MOF), UiO-68, with two hydroxymethyl groups (UiO68-hyd) was synthesized for the first time and the hydroxy groups were post-synthetically modified with iso(thio)cyanates to form (thio)urethanes. Several organotins and tertiary amines were used as catalysts for the modification of UiO68-hyd with butyl isocyanate (BuNCO), and 70% of hydroxy groups reacted after 7 days. Moreover, various isocyanate and isothiocyanate compounds were successfully modified on UiO68-hyd.

DOI： 10.1246/cl.180955

Publishing type：Research paper (scientific journal)  

© 2018 the Society of Polymer Science, Japan. After the disaster in Deepwater Horizon oil spill in 2010, the development of sorbents for organic solvents including oil has been attracting considerable interest among material scientists, due to increase of social interest against the large-scale pollution to natural environment. In this account we summarize recent advances in designing such sorbents with high efficiency by the two different approaches. One is super-absorbent polymers for organic solvents with high swelling ability. The other is highly porous and hydrophobic materials with large surface areas such as sponges and carbon aerogels. Both of them have high sorption efficiency for organic solvents, and most of the latter have good performances for separation of oil from oil-water mixture.

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley-VCH Verlag  

In this study, we performed conductometry in various organic solvents to directly detect the transformation from tetrabutylammonium chloride (TBACl) ion-pair salt to the free ions through complexation with meso-octamethylcalix[4]pyrrole (CP), which is a well-known receptor for chloride anions. In the presence of CP, the conductivity of TBACl increases in various non-polar solvents, indicating that complexation with CP enhances the ionic dissociation of TBACl in such non-polar solvents. In other words, CP recognizes chloride as an ion-paired salt as well as a free anion in non-polar solvents. Additionally, the TBA(CP–Cl) complex exhibited a considerably lower ion-pairing constant (Kip) than TBACl in non-polar solvents, resulting in enhanced conductivity. Based on these findings, we can conclude that complexation of an anion with a hydrophobic anion receptor will be useful for creating functional and stimuli-responsive soft materials in organic solvents using coulombic forces.

DOI： 10.1002/open.201800014

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

Biomineralization has been given a great deal of attention by materials chemists because of its low environmental load and sustainability. With the goal of synthesizing such processes, various methods have been developed, especially for inorganic salts of calcium. In this report, we focused on the deposition of inorganic salts, such as calcium carbonate and calcium phosphate using crystal crosslinked gels (CCG), which are prepared by crystal crosslinking of metal-organic frameworks (MOFs). Due to the crystalline nature of MOFs, CCGs intrinsically possess polyhedral shapes derived from the original MOF crystals. As the result of deposition, the obtained inorganic salts also exhibited a polyhedral shape derived from the CCG. The deposition mainly occurred near the surface of the CCG, and the amorphous nature of the deposited inorganic salts was also confirmed.

DOI： 10.3390/gels4010016

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

Aggregation-induced emission (AIE) has emerged as a new class of attractive photoluminescence behavior. Understanding the precise mechanism of the AIE phenomenon will lead to the rational molecular design of novel molecules with AIE properties (AIEgens). In this work, we selected disubstituted derivatives of tetraphenylethene (TPE), a well-known archetypal AIEgen, as the model compounds to elucidate the AIE mechanism. As the result of photochemical experiments and quantum chemical computations, π-bond twist (π twist), including E-Z isomerization (EZI), was found to be the major factor for quenching the photoexcited state of TPE derivatives in the solution state, differently from the well-accepted propeller-like rotation of the side phenyl groups in earlier research. In photochemical experiments, the prepared TPE derivatives exhibited EZI in the solution state upon photoirradiation, and a negative correlation was observed between this isomerization and the AIE phenomenon. The theoretical computations verified the crucial role of π twist triggered by photoirradiation in the solution state, rather than intramolecular rotation. In the crystal state, π twist was efficiently suppressed by the surrounding molecules. Our results will support the realization of novel smart AIEgens that can respond to various external stimuli.

DOI： 10.1021/acs.jpcc.7b11248

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Herein, we demonstrate a polyelectrolyte gel which can absorb a wide range of organic solvents from dimethylsulfoxide (DMSO, permittivity: epsilon = 47.0) to tetrahydrofuran (epsilon = 5.6). The gel consists of polystyrene chains with small amounts (similar to 5 mol%) of lipophilic electrolytes derived from triphenylphosphonium tetraaryl borate. The swelling ability of the polyelectrolyte gel was higher than that of the alkyl ammonium tetraaryl borate previously reported by us, and this is attributed to the higher compatibility with organic solvents, as well as the higher dissociating ability, of the triphenyl phosphonium salt. The role of the ionic moieties was additionally confirmed by post modification of the polyelectrolyte gel via a conventional Wittig reaction, resulting in a nonionic gel. Our findings introduced here will lead to a clear-cut molecular design for polyelectrolyte gels which absorb all solvents.

DOI： 10.1039/c7sm01841j

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

We aim to control the photoluminescence property of co-crystals derived from an aggregation-induced emission luminogen (AIEgen) through other components in the co-crystal. For this purpose, we prepared co-crystals of a typical AIEgen, tetraphenylethene having four hydroxy groups (THPE), and hydrogen-bond acceptors (HBAs) containing nitrogen atoms. The crystallographic study showed that the HO hydrogen-bonding pattern and inclusion of crystallization solvents are significantly influenced by the employed HBA, depending on the size, position of nitrogen atoms, and basicity of the HBA, thanks to the moderate hydrogen-bonding ability of THPE. The photoluminescence properties of the co-crystals are governed by the employed HBA, and thus, co-crystals derived from imidazole derivatives or 1,4-diazabicydo[2.2.2]octane exhibit intense photoluminescence, while those from pyridine derivatives and an electron-deficient imidazole derivative do not show any photoluminescence. The involvement of photoinduced electron transfer causes quenching of the co-crystals derived from pyridine derivatives, which is confirmed by theoretical computations. These observations imply that the photoluminescence properties of co-crystals derived from AlEgens can be tuned through other components in the co-crystal.

DOI： 10.1021/acs.cgd.8b00141

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

New polymer capsules (PCs) were obtained using a crystal crosslinking (CC) method on core-shell MOF crystals. The latter are based on the epitaxial growth of two isostructural coordination polymers which are then selectively crosslinked. Decomposition of the non-reticulated phase leads to new PCs, possessing a well-defined hollow cubic shape reflecting the heterostructure of the template.

DOI： 10.1039/c7cc07158b

Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Water-in-oil emulsion systems have recently attracted much attention in various fields. However, functionalization of water-in-oil emulsion systems, which is required for expanding their applications in industries and research, has been challenging. We now demonstrate the functionalization of a water-in-oil emulsion system by anchoring a target protein molecule. A microtubule (MT) associated motor protein kinesin-1 was successfully anchored to the inner surface of water-in-oil emulsion droplets by employing the specific interaction of nickel nitrilotriacetic acid histidine tag. The MTs exhibited a gliding motion on the kinesin-functionalized inner surface of the emulsion droplets, which confirmed the success of the functionalization of the water in-oil emulsion system. This result would be beneficial in exploring the roles of biomolecular motor systems in the cellular events that take place at the cell membrane and might also contribute to expanding the nanotechnological applications of biomolecular motors and water-in-oil emulsion systems in the future.

DOI： 10.1021/acs.langmuir.7b01550

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Molecular design of stimuli-sensitive polymers has been attracting considerable interest of chemists because of their latent ability to achieve smart materials. Heat, light, pH, and chemicals have been often utilized as a stimuli inducing polymer phase transition from solution to aggregation and vice versa. In this report, as a new trigger for lower critical solution temperature (LCST)-type polymer phase transition, we introduce organic reaction of small organic molecules, not to the polymer chain itself. The addition of the reactant for the "effector", which can interact with the polymer chain for increasing the compatibility of the polymer chain with the media, caused a polymer phase separation, due to reduction of the solvation ability of the effector to the polymer chain. In other words, decrease of the "effector" concentration induced the polymer phase separation. Within our knowledge, this is the first report to connect a polymer phase separation with organic reaction dynamics. This process will be the first step for the development of artificial allosteric enzyme mimics from a combination of a simple synthetic polymer and a product or reactant in organic reactions.

DOI： 10.1021/acsmacrolett.7b00315

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

The artificial construction of anisotropic deforming materials is one of the great challenges in materials and polymer chemistry. In this paper, we demonstrate a unidirectionally deformable material with reversibility. First, crystal crosslinking of a pillared-layer metal-organic framework (PLMOF) was accomplished, followed by the exchange of the pillar ligand with the monotopic ligand. The obtained crosslinked MOF crystal showed reversible unidirectional compression and expansion during cycles of drying and immersion in good solvents. The macroscopic unidirectional deformation was derived from microscopic variations in the layer distance in the MOF crystal. The polymerization between the organic ligand and the crosslinker effectively reinforced the MOF crystal, which had enough durability for reversible unidirectional deformation. Our strategy is a promising general method for the construction of anisotropic deforming materials, which are often seen in biological systems and mechanical devices.

DOI： 10.1038/pj.2017.32

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

The preparation of the polymers having a self-attractive urea unit via hydrogen bonding and a selfrepulsive lipophilic ion unit via electrostatic interaction was carried out to achieve the thermoresponsivity of polymer solution. The solubility of the obtained copolymers depended on the balance between the attractive force induced by hydrogen bonding among the urea units and the repulsive force attributed to the dissociation of the ionic units. In aprotic and nonpolar solvents, the solubility of the polymers was changed from insoluble to soluble with the increasing content of the ionic units. Moreover, in acetonitrile and 1,2-dichloroethane, the UCST-type thermoresponsivity was observed. This result indicated that the UCST-type thermoresponsivity was induced by cleavage of the hydrogen bonds among urea units upon heating, and at the cloud point, the repulsive force among the ionic units overwhelmed the attractive force. From the result of this research, we would like to emphasize that the combination of a lipophilic ion pair and other self-attractive units can be a simple principle for the molecular design of UCST-type thermoresponsive polymers in any media.

DOI： 10.1039/c7py00591a

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Polymer gels, a representative state of network polymers, are a valuable and well-known class of materials with various functional and attractive properties and are thus commonly used in daily life. The properties of a polymer gel depend not only on the chemical structure of the network but also on the physical structure, including crosslinking points, polymer chains or network compositions, as demonstrated by recent studies on polymer gels with elaborate physical structures. By using a new type of porous crystal, a metal-organic framework (MOF) consisting of organic ligands and metal ions, as the key material, several research groups have developed a synthetic procedure for the formation of network polymers with highly controlled structures. This review focuses on the integration of MOFs and organic network polymers to form shaped network polymers or organic-inorganic hybrid networks through the following three methods: (1) polymerization of the organic ligands in a MOF using the guest molecules, (2) polymerization of homopolymerizable organic ligands in a MOF in the absence of guest molecules, and (3) formation of MOFs from polymeric organic ligands.

DOI： 10.1038/pj.2016.122

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

According to the design of disassembly using electrostatic repulsion, novel amphiphiles consisting of a lipophilic ion part and a hydrophilic saccharide part were synthesized via the facile copper-catalyzed click reaction, and their molecular assemblies in water and chloroform were studied. The amphiphiles exhibited a molecular orientation opposite to that of the conventional amphiphiles in each case. zeta Potential measurements indicated that the lipophilic ion part is exposed outside in chloroform. The size of a solvophobic part in the amphiphiles dominates the size of an assembling structure; that is, in water, these amphiphiles tethering different lengths of the saccharide part exhibited almost identical assembling size, whereas in chloroform, the size depends on the length of the saccharide part in the amphiphiles.

DOI： 10.1021/acs.langmuir.6b04360

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Anisotropically deforming objects have attracted considerable interest for use in molecular machines and artificial muscles. Herein, we focus on a new approach based on the crystal crosslinking of organic ligands in a pillared-layer metal-organic framework (PLMOF). The approach involves the transformation from crosslinked PLMOF to polymer gels through hydrolysis of the coordination bonds between the organic ligands and metal ions, giving a network polymer that exhibits anisotropic swelling. The anisotropic monomer arrangement in the PLMOF underwent axis-dependent crosslinking to yield anisotropically swelling gels. Therefore, the crystal crosslinking of MOFs should be a useful method for creating actuators with designable deformation properties.

DOI： 10.1002/anie.201611338

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A typical AIE dye, TPE, was liquefied by attaching long and branched alkyl chains. The obtained liquid dye showed intense emission compared to the solid dye or TPE. The linkage between TPE and the alkyl chain led to significant difference in their photoluminescent and thermal properties.

DOI： 10.1039/c6cc09939d

Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

The synthesis and photoluminescence properties of crystal crosslinked gels (CCGs) with an aggregation-induced emission (AIE) active crosslinker derived from tetraphenylethene (TPE) is discussed in this article. The CCG was prepared from a metal organic framework (MOF) with large pore aperture to allow the penetration of TPE crosslinker. The obtained CCG possessed a rectangular shape originated from the parent MOF, KUMOF. The CCG showed stimuli-responsive photoluminescence behavior depending on the swelling degree, thus the photoluminescence intensity was higher at higher swelling degree. By changing the solvent, water content, or ionic strength, the photoluminescence intensity was controllable, accompanying the change of swelling degree. Moreover, emission color tuning was also achieved by the introduction of luminescent rare earth ions to form a coordination bonding with residual carboxylate inside the CCG.

DOI： 10.3390/polym9010019

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

We report on the synthesis of nanosized single-crystalline spherical beta-Ga2O3 particles (GONP) by thermal annealing of gallium nanoparticles (GaNP), which previously has been prepared under ultrasonication. GONP displayed a spherical morphology and the particle size reflected that of GaNP. The nanoparticles have been confirmed crystalline beta-Ga2O3 by powder X-ray diffraction. The selected area electron diffraction patterns obtained from a whole particle of one GONP represented production of single-crystalline nanoparticle. Furthermore, the dispersibility and stability of GONP in solvent dramatically improved through silica coating (GO@SiO2 NP). Photoluminescence spectroscopy indicated that the GO@SiO2 NP exhibited a light blue emission at 445 nm under excitation at 240 nm. Diffuse reflectance spectroscopy demonstrated that the band gap of GO@SiO2 NP (E-g = 4.89 eV) was hypsochromically shifted compared to that of bulk Ga2O3 (E-g(bulk) = 4.56 eV) due to the quantum size effect of beta-Ga2O3. Additionally, silica particle-supported GONP (GONP/MCM-41) showed catalytic activity for the benzylation of benzene with benzyl chloride. Thus, the GONP presented here will have potential applications in LED phosphors, optoelectronic devices, and supported catalysts.

DOI： 10.1039/c6ra26085c

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Metal-organic frameworks (MOFs) are well-ordered microporous crystalline materials synthesized from metal cluster nodes and organic ligands. Using organic ligands with functional and reactive moieties enables post-synthetic modification (PSM) for further functionalization of MOFs. In this study, bioconjugation of MOFs with functional motor proteins, such as kinesin microtubule (MT) system was investigated by employing PSM. Kinesin-MT system, energy diffusive gliding motion of MT was performed by consuming chemical energy of adenosine-triphosphate (ATP) in vitro. Thus, we attempted establishment of gliding of MOF by applying bio-motor system, in which reconstituted MT filaments are propelled over a kinesin-coated substrate in the presence of ATP.

DOI： 10.1002/slct.201601431

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

In this paper, mesogenic polyelectrolyte gels (MPEgels) tethering mesogenic groups on the side chains were synthesized from a mesogenic monomer and ionic monomer via a conventional radical polymerization process. The obtained MPEgels absorbed various organic solvents in a wide range of dielectric constants from chloroform (epsilon = 7.6) to DMSO (epsilon = 46.5). The electrostatic repulsion among the polymer chains and the osmotic pressure between the interior and exterior of the MPEgel is responsible for the high swelling ability, revealed by the common ion effect using tetra(n-hexyl) ammonium tetra(3,5-bis(trifluoromethyl) phenylborate (THATFPB). The obtained MPEgels could also absorb liquid crystalline molecules such as 4-cyano-4'-pentylbiphenyl (5CB), analogously caused by the above-mentioned polyelectrolyte characteristic. The MPEgels exhibited liquid crystal transition temperature (T-NI) on differential scanning calorimetry (DSC) measurement, and the increase of the ionic group content lowered T-NI. The MPEgels absorbing liquid crystalline molecules exhibited differing T-NI, dependent on the compatibility of the mesogenic group on the side chain to the liquid crystalline molecule.

DOI： 10.3390/polym8040148

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

In this study, polystyrene (PS) ionomers having tetraalkylammonium with a series of counterions are prepared with various feed ratio of the ionic units and blended with nonionic poly(n-butyl methacrylate) (PBMA) which is originally immiscible with PS. According to differential scanning calorimetry analysis, in the blends of ionomers with tetraarylborate and PBMA, the ionomers with more than 1 mol% of the ionic units are completely miscible with PBMA. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction measurements reveal that the bulky and lipophilic ion-pair inhibits the association of ions and instead induces the attractive interaction to alkyl groups of PBMA. Tensile tests of the miscible specimen exhibit both characteristic behavior, that is, high tensile strength as PS and high elongation property of PBMA.

DOI： 10.1002/macp.201500281

Publishing type：Research paper (scientific journal)  

DOI： 10.11364/networkpolymer.37.88

Language：English   Publishing type：Part of collection (book)   Publisher：Springer Japan  

Topochemical polymerizations have been attracting continuous interest as one of the precise polymerizations in a confined space. However, it is still not easy for designing new monomers due to difficulty in designing and controlling the arrangement suitable for topochemical polymerization. In this chapter, we shortly review polymerization in a confined space and demonstrate recent advances in topochemical polymerizations, providing the molecular orientations for various topochemical polymerization monomers. Then, we propose a new type of topochemical polymerization by use of metal organic framework (MOF). MOF is nano-porous crystalline materials constructed by metal ions and rigid organic ligands equipped with two or more ligation sites to form robust 3D host framework with nano-pores. The void space between them is wide and stable, which prompted us to investigate cross-linking of the organic ligands as the host monomers by the external guest monomers by means of two chemical reactions: (1) azide-tagged MOF (AzMOF) cross-linked by multi-alkyne cross-linkers via click reaction and (2) cyclodextrinMOF (CDMOF) cross-linked by diglycidyl ethers. They should be new crystalline-state polymerization, because the cross-linking took place without any movement of the host monomers in the open-host framework.

DOI： 10.1007/978-4-431-55555-1_26

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Lipophilic polyelectrolyte gels capable of large swelling in low-polar solvents (3 <= epsilon <= 10) were developed by Ono et al. ( Nature Mater. 2007), where e is the dielectric constant. These gels were prepared by introducing tetraphenylborate as a lipophilic anion (tetrakis(3,5-bis(trifluoromethyl)phenyl)borate; TFPB) and tetraalkylammonium with long alkyl chains as a lipophilic cation (tetra(n-butyl)ammonium; TBA(+)) into a poly(octadecyl acrylate) (pODA) backbone chain. Here, we investigated the structure of the lipophilic polyelectrolyte gels and corresponding polymer solutions in CH2Cl2 with small-angle neutron scattering (SANS) and dynamic light scattering (DLS). From SANS, it was revealed that individual pODA chain is regarded as a rod with the cross-section radius of 15 angstrom and the length of ca. 160 angstrom and is little changed by introduction of charges or cross-linking. In addition to this, it was revealed from SANS measurements that the second virial coefficient of pODA in CH2Cl2 was positive. In combination with DLS measurements, we observed several characteristic features similar to polyelectrolyte aqueous systems such as (i) the clear appearance of slow diffusional motion in polymer solutions, (ii) an increase of diffusion coefficient in gels, and (iii) an increase of osmotic modulus in solutions and gels when ionic groups are incorporated in pODA. These experimental findings clearly show that [TBA(+)][TFPB-] dissociates enough and pODA, accompanying these ionic groups, acts as a polyelectrolyte even in a low-polar solvent such as CH2Cl2 (epsilon = 8.9). It is concluded that the good compatibility of pODA with CH2Cl2 and the introduction of dissociable ionic groups into pODA result in high-swelling capability of the lipophilic polyelectrolyte gels.

DOI： 10.1021/acs.macromol.5b00753

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

In this paper, we prepared various network polymers with crosslinkers having two or four acryloyl groups derived from an AIE luminogen, and investigated the relationship between the rigidity of network polymers and emission behaviour. The crosslinkers showed representative AIE properties. A conventional radical polymerization with various vinyl monomers produced corresponding network polymers. The variation of vinyl monomers or the crosslinkers allowed us to obtain network polymers with different rigidities. Fluorescence spectroscopy of the network polymers revealed rigidity dependent emission enhancement accompanying the hypsochromic shift. In addition, the network polymer showed temperature and solvent dependent emission behaviour. The crosslinker with less crosslinkable substituents showed higher susceptibility toward the environmental conditions such as rigidity, temperature, and solvent.

DOI： 10.1039/c5tc01597a

Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)  

DOI： 10.20665/kakyoshi.63.10_490

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

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A novel gel LCST system consisting of a pyrene containing acrylate network polymer and external effectors is demonstrated. The LCST behaviour was conducted by switching of the CT interaction between the gel and effector, which was readily tuned by effector concentration or molecular structure of the effector.

DOI： 10.1039/c5ra18388j

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A smart metal-organic framework (MOF) exhibiting controlled release was achieved by modification with a thermoresponsive polymer (PNIPAM) via a surface-selective post-synthetic modification technique. Simple temperature variation readily switches "open'' (lower temperature) and "closed'' (higher temperature) states of the polymer-modified MOF through conformational change of PNIPAM grafted onto the MOF, resulting in controlled release of the included guest molecules such as resorufin, caffeine, and procainamide.

DOI： 10.1039/c5cc02339d

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

We synthesized a tetravinyl ME luminogen based on tetraphenylethene (TPE-CL), followed by its reaction with H-terminated PDMS via hydrosilylation to construct ME elastomers. NMR and IR spectroscopy studies showed facile progress of the preparative reaction. The obtained sample strips represented typical elastomeric behavior revealed by tensile test, while the mechanical properties were varied by the chain length of employed PDMS. The homogeneous distribution of TPE-CL in an elastomer was confirmed by UV-vis absorption spectra variation upon increase of TPE-CL content. The elastomers exhibited stimuli-sensitive fluorescence against organic solvents and temperature, and the responsiveness was found to be reversible. These characteristics are clearly derived from ATE property of TPE-CL, which is sensitive to intramolecular rotation.

DOI： 10.1021/ma501198d

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Facile mixing of a liquid metal, organic medium, and surfactant by sonication provided well-dispersed and uniformly sized gallium nanoparticles (GaNP). Furthermore, transformation to other noble metal nanoparticles having a similar size distribution was achieved via metal exchanging redox process utilizing the GaNP as the precursor.

DOI： 10.1246/cl.140359

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Herein, we describe the preparation of lipophilic polyelectrolyte brush (LPB) and its morphology variation induced by immersing in various organic solvents. In particular, the use of 1,2-dichloroethane resulted in twining of large fibers due to the extension of polymer chains, caused by both good compatibility of nonionic moiety and dissociation of ionic moiety. To our best knowledge, this is the first example for PE brush functioning in nonpolar organic media.

DOI： 10.1246/cl.140341

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

Publishing type：Research paper (scientific journal)  

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

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

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Stimuli-responsive polymer gels can drastically change their volume in response to various external physical and chemical stimuli. The smart polymer gels for specific chemical substances have been extensively studied as applications for molecular recognition or supramolecular chemistry in the material sciences toward intelligent materials. This review article highlights recent advances in the molecular design of stimuli-responsive polymer gels triggered by molecular recognition, especially by the recognition of ionic species. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.reactfunctpolym.2013.02.009

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Practical and functional surface-enhanced Raman scattering (SERS)-active nanomaterials working in solution require a protecting shell. In this study, we demonstrate the fabrication of gold nanorods coated by metal organic frameworks of several hundred nanometers in size, which is one kind of crystalline porous materials, as s suspension-based SERS sensor. The composites also showed enough stability and reproducibility for detection of the guest molecules.

DOI： 10.1021/cm302735b

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

Cool down and get it together! The lower critical solution temperature (LCST) behavior of a polymer containing pyrene units was controlled by a charge-transfer (CT) interaction with an electron-accepting effector (see picture). The appearance of CT bands enabled quantitative evaluation of the thermodynamics of the association. Copyright © 2013 WILEY-VCH Verlag GmbH &amp
Co. KGaA, Weinheim.

DOI： 10.1002/anie.201210261

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Until now, seamless fusion of metal organic frameworks (MOFs) and covalently cross-linked polymer gels (PG) at molecular level has been extremely rare, since these two matters have been regarded as opposite, that is, hard versus soft. In this report, we demonstrate transformation of cubic MOF crystals to PG via inner cross-linking of the organic linkers in the void space of MOF, followed by decomposition of the metal coordination. The obtained PG behaved as a polyelectrolyte gel, indicating the high content of ionic groups inside. Metal ions were well adsorbed in the PG due to its densely packed carboxylate groups. A chimera-type hybrid material consisting of MOF and PG was obtained by partial hydrolysis of resulting cross-linked MOF. The shape of resulting PG network well reflected the crystal structure of MOF employed as a template. Our results will connect the two different network materials that have been ever studied in the two different fields to provide new soft and hard hybrid materials, and the unique copolymerization in the large void space of the MOF will open a new horizon toward "ideal network polymers" never prepared before now.

DOI： 10.1021/ja3125614

Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Novel anionic and lipophilic polymer networks have been successfully synthesized by imine formation between tetraphenylborates and 1,4-phenylenediamine. The obtained polymer networks showed various morphologies depending on the dielectric constant of media used in the synthesis. Moreover, the addition of water led to polymer networks with spherical structure presumably due to suppression of imine formation.

DOI： 10.1246/cl.2012.667

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The de novo design of thermosensitive polymers in solution has been achieved by using the addition of small organic molecules (or "effectors"). Hydrogen bonding as an attractive polymer-polymer or polymer-effector interaction substantially dominates the responsivity, causing facile switching between LCST-type and UCST-type phase transitions, control of the transition temperature, and further coincidence of the two transitions. Small molecules having a high affinity for the polymer induce UCST-type phase behavior, whereas those having a low affinity for the polymer showed LCST-type phase behavior.

DOI： 10.1021/ja301688u

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Facile conversion of azide to primary amine in metal-organic frameworks (MOFs) was accomplished by Staudinger reduction. After the reaction, MOFs retained high crystallinity confirmed by X-ray diffraction patterns, meaning a high usability of this method for post-synthetic modification of MOFs. Bulky phosphine groups provided surface-selective modification of MOFs via a reaction between resulting amine groups of MOF and activated ester with fluorescein, illustrated by confocal laser scanning microscope (CLSM) observation. This method opens up new possibilities for the preparation of MOFs having core-shell structures.

DOI： 10.1039/c2ce06633e

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

DOI： 10.1002/anie.201204919

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Stimuli-responsive gels that can change their volumes drastically in response to various external physical and chemical stimuli have been of much interest due to their various applications. Herein, novel stimuli-responsive gels were achieved through the complexation between anion receptors and the chloride anion of polystyrene ionomer gels in aprotic organic solvents. The volume expansions induced by the addition of the receptors originated from breaking the aggregation of ionic groups and enhancing the dissociation of the ion-pairs, accompanied by their colour changes.

DOI： 10.1039/c2sm25994j

Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

pi-Conjugated systems connected to o-carborane undergo enhancement of luminescence from boron dipyrromethene (BODIPY) dyes via encapsulation and energy transfer in aqueous media. The inhibition of H-aggregation formation in aqueous media effectively regains the emission from luminophores. (C) 2010 Published by Elsevier Ltd.

DOI： 10.1016/j.tetlet.2010.11.026

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

We demonstrate multicolor tuning of aggregation-induced emission (AIE) derived from o-carborane. Both electron-donating and electron-accepting arylacetylenes underwent efficient palladium coupling reaction with bis(4-bromophenyl)-o-carborane, resulting in moderate yields. The emission spectra of these compounds span almost the entire visible spectrum (lambda(max) = 452-662 nm). Study on AIE mechanism indicated that CT-based emission of o-carborane derivatives was enhanced by the restriction of molecular motions. The computational study also suggests the possibility of precise color-control of AIE through substituent variation.

DOI： 10.1021/jo101999b

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

We designed a novel ditopic bisterpyridyl ligand containing o-carborane that can construct a coordination polymer by complexation with metal ions. Through the use of Sonogashira-Hagihara coupling, the desired ligand molecule was successfully synthesized. Addition of Zn(II) ions rapidly underwent the generation of a fluorescent coordination polymer, which was confirmed by H-1 NMR, UV-vis, and fluorescent titration experiments. Furthermore, the electronic structure of the bisterpyridyl ligand molecules was drastically changed upon the complexation with metal ions. The obtained coordination polymer showed light blue emission derived from the intraligand charge transfer (ILCT) state, whereas a bare ligand molecule exhibited yellowish-green aggregation-induced emission (AIE) in a poor solvent such as water, because of the variable C C bond in o-carborane.

DOI： 10.1039/c1dt90011k

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Well-defined poly(N-isopropylacrylamide)s (PNIPAMs) with boron dipyrromethene (BODIPY) in the terminal end were prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization of NIPAM with BODIPY-chain transfer agent (CTA), which was synthesized by the reaction of pyrrole and BODIPY derivative having benzyl chloride in the meso position. The controlled character of the polymerization of NIPAM was confirmed by the formation of the narrow molecular weight distribution products and linear increase of molecular weight with the feed ratios of [NIPAM)/[CTA]. The RAFT-prepared PNIPAM exhibited strong green luminescence with emission maxima at 558 nm upon excitation with the absorption maxima at 526 nm and was used for the aqueous synthesis of stabilized gold nanoparticles (AuNPs). The in situ reduction of the RAFT-prepared polymers and HAuCl4 resulted in the formation of stable modified AuNPs with size distributions of similar to 10 nm in water solution. Temperature-dependent change in photoluminescence (PL) spectra (excited at 526 nm) of the RAFT-prepared polymers measured in water showed an increase in emission intensity with the rise at temperature (20 -> 40 degrees C). On the contrary, AuNPs exhibited a decrease in emission intensity with increasing of temperature, resulting that shrinking of the distance between BODIPY units and Au core in the AuNP across border LCST gives rise to both quenching of emission of BODIPY unit by Forster resonance energy transfer (FRET) and dye quenching of aggregated BODIPY units. The emission/quenching of AuNP occurs reversibly and efficiently, regardless of the heating and cooling cycle.

DOI： 10.1021/la102597y

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

A series of pi-conjugated polymers linked by benzocarborane (1,2-(buta-1&apos;,3&apos;-diene-1&apos;,4&apos;-diyl)-1,2-dicarbadodecaborane) were synthesized via Sonogashira-Hagihara polycondensation reaction. The opened molecular structure of diiodo monomer containing benzocarborane resulted in fast polymerization and high molecular weights. The obtained polymers were fully characterized by (1)H, (13)C, and (11)B NMR spectroscopies. UV-vis absorption and photoluminescence studies revealed the acceptor-profile of benzocarborane. Unlike the polymers linked by o-carborane, these polymers exhibited strong luminescence in the solution state, presumably because the inductive effect of carborane is dominant, rather than cage-pi interactions.

DOI： 10.1002/marc.201000160

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

We demonstrate the synthesis cola novel diglycidyl compound exhibiting aggregation-induced emission (AI E) derived from o-carborane, and employed it as a cross-linking reagent to prepare translucent hydrogels consisting of poly(gamma-glutamic acid). Swelling ratio of the obtained hydrogels depended on the cross-linking density. Higher cross-linking density of the obtained hydrogels led to stronger emission in the swollen state, and finally the absolute quantum yield reached 0.10, which is directed to that of cross-linker with AI E in water dispersion (Phi(F) = 0.19). The luminescence character of lower cross-linked hydrogels was drastically influenced by the gel-shrinkage from the change of ionic strength. Furthermore, these hydrogels showed effective reversible fluorescence switching between the swollen and dried states.

DOI： 10.1021/ma100792z

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Polymer reactions of poly(p-phenylene ethynylene) (PPE) based on the addition reaction of decaborane to the carbon-carbon triple bond were successfully carried out. The platform polymer was synthesized through Sonogashira-Hagihara coupling polymerization. The effective introduction of the boron cluster, and thus the subsequent formation of o-carborane, was supported by (1)H and (11)B nuclear magnetic resonance spectroscopies. The introduction rate of decaborane to the polymer main chain was proportional to the feed ratio of decaborane. Ultraviolet-visible absorption and photoluminescence studies illustrate the shortening of the effective pi-conjugation length caused by the introduction of carborane clusters. Furthermore, the introduction of the boron cluster by the polymer reaction efficiently enhanced the heat resistance of PPE. Polymer Journal (2010) 42, 363-367; doi:10.1038/pj.2010.13; published online 17 March 2010

DOI： 10.1038/pj.2010.13

Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS INC  

Nitroxide-mediated radical polymerization has been used for the preparation of pentafluorostyrene (PFS) homopolymers and random copolymers of PFS and oligo(ethyleneglycol) methacrylate (OEGMA(8.5)). The poly(pentafluorostyrene) homopolymers were reacted with thiophenol at different ratios at room temperature in the presence of triethylamine. The "clicked" polymers were characterized by (1)H and (19)F NMR spectroscopy and size exclusion chromatography. Moreover, the copolymerization kinetics of the PFS and OEGMA(8.5) copolymers was followed, and the phase transition behavior of random copolymers with different compositions was discussed. Furthermore, copolymers of PFS and 2-(dimethylamino) ethyl methacrylate (DMAEMA) were prepared at various mole ratios, and the copolymer with a 10:90 ratio, respectively, was soluble in water at room temperature. Turbidimetry measurements were performed for PFS and OEGMA(8.5) or DMAEMA copolymers to determine their cloud points. Finally, the PFS and OEGMA(8.5) copolymer with a mole ratio of 60:40 was reacted further with thiophenol to increase the hydrophobic part in the copolymer. The cloud points of the obtained copolymers could be tuned from 87 to 33 degrees C by using not only the controlled radical polymerization but also the "click" reaction in a controlled fashion. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1278-1286, 2010

DOI： 10.1002/pola.23872

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

Novel water-soluble copolymers containing 4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) dyes were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. The copolymers with both number-average molecular weight between 5.0 x 10(3) and 5.8 x 10(3) and narrow molecular weight distribution (M-w/M-n < 1.19) were obtained by the copolymerization of (2-dimethylamino)ethyl methacrylate (DMAEMA) and BODIPY-based methyl methacrylate (1) with 2,2'-azobis(isobutyronitrile) (AIBN) as an initiator in the presence of cumyl dithiobenzoate (CDB) as a chain transfer agent (CTA). The structures of the resulting copolymers were characterized by H-1, C-13, and B-11 NMR spectroscopies, and the comonomer compositions were good consistent with the feed ratio. Characteristic optical properties of the obtained copolymers were investigated by UV-vis and PL spectroscopic methods. The copolymers composed of [DMAEMA]: [1] = 98.0:2.0 and 99.4:1.4 led to thermoresponsive polymers having phase separation temperatures at 32 degrees C and 40 degrees C, respectively, depending on the compositions of hydrophilic/hydrophobic balances. Further, the effective reversible decrease/increase of the emission intensity of the copolymers led to the reversible formation/inhibition of the H-aggregation between two BODIPY planes in the copolymers on heating and cooling across the border of LCST. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 627-634, 2010

DOI： 10.1002/pola.23813

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Chiral rod-coil-type organoboron polymers S-poly and R-poly were prepared from the palladium-catalyzed Sonogashira-Hagihara coupling reaction of boron dipyrromethene-based monomer 1, which has bisiodophenyl and decyl groups with S- or R-6,6'-diethynyl-2,2'-dioctyloxy-1,1'-binaphthyls (S-2 and R-2), in a solvent mixture (tetrahydrofuran (THF)/triethylamine=2/1 (v/v)) at 40 degrees C for 24h. The obtained polymers were characterized by hydrogen-1 nuclear magnetic resonance (NMR), carbon-13 NMR (C-13 NMR), boron-11 NMR (B-11 NMR) and infrared spectroscopy. The scanning electron microscopy (SEM) analysis of each chiral polymer clearly revealed micrometer-sized fiber-like structures formed by the aggregation of each particle, as we expected. Next, we examined the relationship between the ratio of photoluminescence (PL) intensity (I/I-o=R-poly/S-poly) and particle diameter, measured by dynamic light scattering analysis, versus the R-poly content of the mixed polymer of S-poly and R-poly in THF, which varied from 0 to 100%. As a result, the PL intensity and diameter showed maximum and minimum (about 32 nm) values, respectively, at 70% content, depending on the differences between both the molecular weights and absolute values of the chiral characters. These findings indicate that the PL intensity of S-poly influences morphology change by adding R-poly; that is, R-poly acts as an inhibitor toward the aggregation of S-poly. Furthermore, the SEM image of the mixed polymer (S-poly/R-poly=30/70) showed complete particle structures from nano- to micrometer sizes, which were roughly 480 nm to 1.19 mu m in diameter, and the Phi(F) of the mixed polymer was significantly high (0.98). Polymer Journal (2010) 42, 37-42; doi:10.1038/pj.2009.302

DOI： 10.1038/pj.2009.302

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

pi p-Conjugated copolymers composed of 9,9-didodecylfluorene and boron quinolate were synthesized by an efficient chelating reaction of quinolinol-based polyfluorene derivative, as a polymeric ligand, with arylborane compounds such as triphenylborane (BPh3) or fluorobis(pentafluorophenyl) borane diethyl etherate ((C6F5)BF center dot OEt2). The polymeric ligand was prepared from the deprotection reaction of boron tribromide and benzyloxyquinoline-based polyfluorene, which was produced via the efficient Suzuki cross-coupling reaction of 5,7-dibromo-8-benzylquinoline and 9,9-didodecylfluorene-2,7-diboronic acid in the presence of 2-(2',6'-dimethoxybiphenyl)dicyclohexylphosphine (S-Phos) and palladium(II) acetate. Their optical properties were studied by UV-vis absorption and photoluminescence spectroscopies. The absorption and PL spectra of the obtained polymers were red-shifted in comparison with those of the polymeric ligand due to the decrease of the LUMO level by the formation of boron complexes, explained by theoretical calculations of the model compounds using the density-functional theory (DFT) method. The molar extinction coefficients and emission maxima of boron-chelating polymers were analogous values to those of (kappa(2)-(N,O)-5,7-bis(9,9-dihexylfluoren-2-yl)-8-quinolinolate)diphenylborane (BFluorene(2)q). Furthermore, the electron mobilities of the polymers were determined from the space-charge limited current (SCLC) with electron-only device structure of ITO/Ca/polymer/LiF/Al. As a result, the mobilities for the polymers (3.9 or 2.0 x 10(-5) cm(2)V(-1)s(-1)) were reasonably close to the value (7.9 x 10(-5) cm(2)V(-1)s(-1)) calculated from the Alq(3)-fabricated device.

DOI： 10.1039/b924729g

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Sonogashira-Hagihara polycondensations of two bis(4-iodophenyl)carborane compounds with axially chiral diyne monomers having binaphthyl unit were carried Out to obtain the corresponding chiral pi-conjugated polymers having o- or m-carborane segment in the main chain. The polymer structures and their optical properties were characterized by (1)H, (13)C, and (11)B NMR, FT-IR, UV-vis absorption, photoluminescence, and circular dichroism spectroscopies. Photoluminescence study revealed that the polymer having m-carborane exhibited intense blue emission in Solution state, whereas polymers having o-carborane exhibited aggregation-induced emission (AIE). All polymers showed strong CD signals, indicating the construction of highly ordered conformation.

DOI： 10.1021/ma902094u

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Amphiphilic hybrid pi-conjugated polymers that have polyhedral oligomeric silsesquioxanes on their side chains have been successfully synthesized by the Sonogashira-Hagihara poly-condensation reaction. The obtained polymers were studied with ultraviolet-visible absorption and photoluminescence spectra. In these polymers, the pi-conjugation length was extended along the poly(p-phenylene-ethynylene) backbone. Furthermore, the content of the POSS substituents can influence the aggregation behavior of the polymers and subsequent luminescent properties.

DOI： 10.1002/marc.200900152

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

DOI： 10.1021/ma901001b

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Well-defined polymers incorporated BODIPY dyes into the PMMA side chain, and the block copolymers were synthesized by the RAFT process. The controlled/living character of the polymerization of MMA monomers with pendant BODIPY dyes was confirmed by the formation of the narrow molecular weight distribution products, the linear first-order kinetic plot, linear increase of molecular weight with the conversion, and block extension with styrene. The SEM images of the obtained homopolymers showed micrometer-sized blubber particle- or chain-like structures, which come from the aggregated particles by strong intermolecular pi-pi stacking of BODIPY dyes. In contrast, the designed block copolymers formed nanoparticles with enhanced luminescence (Phi(F) > 0.70) by preventing higher molecular weight polystyrene segment from aggregation by the strong pi-pi stacking.

DOI： 10.1021/ma900840y

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Low-molecular-mass organoboron quinoline-8-thiolate and -selenolate complexes as model compounds, and organoboron polymers incorporated their complex structures into the poly(p-phenylene-ethynylene) main chain were prepared. Tetracoordination states of boron atoms in the obtained compounds were confirmed by B-11 NMR spectroscopy, and the detailed structures of the model compounds were determined by single-crystal X-ray diffraction analysis. The polymers were synthesized by Sonogashira-Hagihara coupling reaction of organoboron quinolate-based monomers having diiodo groups with 1,4-diethynylbenzene derivatives bearing electron-donating or -withdrawing groups in moderate yields. Their optical properties were studied by UV-vis absorption and photoluminescence spectroscopies. Increasing atomic number of the 16 Group atom adjacent to the boron atom caused emission shift to longer wavelength and decreasing of absolute quantum yields for both the model compounds and the polymers. There are no differences between the polymers with the donating pi-conjugated linker and with the accepting one in the photoluminescence property, resulting from efficient energy transfer from pi-conjugated main chain to Q ligand. Furthermore, the obtained polymers showed high refractive indices (n(d) > 1.66).

DOI： 10.1021/ma900008m

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A series of in-carborane-based T-conjugated polymers were successfully synthesized via Sonogashira-Hagihara polycondensation reaction. Diiodo-in-carborane monomer underwent efficient polycondensation reaction with both electron-donating and electron-accepting diyne comonomers. The wide-angle structure of in-carborane monomer allowed the preparation of polymers with high molecular weights (M(n) = 26 600-36 400 g mol(-1)) and good polymerization degrees (DP = 31-56). UV-vis absorption study in dilute CHCl(3) solution revealed. pi-conjugation extension of a p-phenylene-ethynylene segment by introducing in-carborane moieties into the polymer backbone. Further, the lack of C-C bond in the carborane cluster leads to polymers exhibiting intense blue emission in Solution state (Phi(F) = 0.11-0.26).

DOI： 10.1021/ma900174j

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

DOI： 10.1021/ma8027358

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Hydroboration polycondensations of three aromatic dicyano compounds 1, 1,4-dicyanobenzene (1a), 1,3-dicyanobenzene (1b), and 1,4-didodecyloxy-2,5-dicyanobenzene (1c), with N,N,N',N'-tetramethylethylenediamine-bis(monoisopinocampheylborane) (S-IpcBH(2)center dot TMED) were carried out to obtain optically active poly(cyclodiborazane)s (2a, 2b, and 2c) with M s in the range from 2400 to 6800 in 61-76% yields. The hydroboration polycondensation efficiently proceeded through the complete formation of boron-nitrogen four-membered ring. The polymer structures were characterized by H-1 and B-11 NMR, UV-vis, photoluminescence (PL), and CD spectroscopies. Only 2c exhibited intense blue-green light emission from charge-transfer interaction by incorporation of donor and acceptor system into the polymer backbone. The emission behavior of model compounds (A and B), corresponding to polymer units of 2a and 2c, was effectively examined by theoretical calculations using the DFT method. As a result, the intense blue-green emission of 2c was observed by the bathochromic shift to a visible region. All the polymers showed intense CD signals, indicating that they formed chiral boron-nitrogen four-membered ring structure. Further, 3b and 3c were prepared by hydroboration polycondensation of 1b or 1c with R-IpcBH(2)center dot TMED. The specific rotations of 2a, 2b, and 2c showed positive values in contrast to those of 3b and 3c. The Cotton effects of the cyanobenzene moieties in 2a, 2b, and 2c at around 300-350 nm were positive, whereas the Cotton effects of the cyanobenzene moieties in 3b and 3c were negative, as were the specific rotations as well.

DOI： 10.1021/ma802257k

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

DOI： 10.1021/ma801690d

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A novel class of rod-coil type-organoboron polymers with p-phenylene-ethynylene as the rod segment and long alkyl chain (decyl group) as coil segment has been prepared from a Sonogashira-Hagihara coupling reaction of a BODIPY-based monomer having bis-iodophenyl and decyl groups with diyne monomers, 1,4-diethynylbenzene (a), 1,4-diethynyl-2,5bis(trifluoromethyl)benzene (b), and 2,7-diethynyl-9,9-dihexyl-9H-fluorene (c). The characterization by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the strong tendency of the obtained polymers, 2a, 2b, and 2c, to self-assemble into particles in solution and as-casted films on a mu m-nm scale. Especially, 2a showed the presence of nm-sized particles and mu m-sized fiber-like structures formed by aggregation of each particle. Further, in CHCl3, the gelation of 2a by three-dimensional aggregation of each fiber was observed at room temperature after 24 h. Their luminescent properties showed high energy transfer efficiency from pi-conjugated polymer linkers to BODIPY moieties (Phi(F) > 71%).

DOI： 10.1021/ja806939w

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Diarylboron diketonates were successfully prepared by the reaction of 1,3-diketone derivatives and arylboron compounds Such as triphenylborane [BPh3] and fluorobis(pentafluorophenyl)borane diethyl etherate [(C6F5)(2)BF center dot OEt2]. The fluorescent emission of their complexes took place depending on the substituent of the arylboron moiety. In particular, a boron 1,3-bis(4-methoxyphenyl)-1,3-diketonate chelated by a strong electron-withdrawing C6F5 group exhibited the most intense fluorescence.

DOI： 10.1021/jo8017582

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Poly(p-phenyleneethynylene) (PPE) and silica gel polymer hybrids were synthesized from the PPE together with tetramethoxysilane (TMOS) via a sol-gel method by utilizing cationic groups on the side chain of PPEs. Up to 10 wt % of the cationic PPE was able to disperse homogeneously into a silica matrix without any compatibilizer. Compared to amino and ammonium groups, PPE having imidazolium groups exhibited high dispersity in silica gel. The photoluminescence of the cationic PPE was reinforced against the thermal irradiation by the surrounding polymer hybrid matrix.

DOI： 10.1246/cl.2008.732

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Anionic poly(p-phenylene-ethynylene) (PPE) incorporated polymer hybrids were synthesized from the PPE and tetramethoxysilane together with the organic polymers such as poly(vinylpyrrolidone) via a sol-gel method. Up to 10 wt % of the anionic PPE could be dispersed homogeneously in the resulting polymer hybrid matrix. The obtained polymer hybrids exhibited controllable photoluminescence properties by the modification of the internal environment of organic-inorganic polymer hybrids by changing the organic/inorganic ratios. The photoluminescence of the anionic PPE surrounded by the polymer hybrid matrix was reinforced against the thermal irradiation. Moreover, the photoluminescence of the obtained organic-inorganic polymer hybrids was also tuned by utilizing ionic interactions between the anionic PPE and the inorganic matrix. (C) 2008 Wiley Periodicals, Inc.

DOI： 10.1002/pola.22719

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC POLYMER SCIENCE JAPAN  

Pyrene-incorporated organic-inorganic polymer hybrids were synthesized from methacryloyl monomers, tetramethoxysilane (TMOS) and pyrene via the in situ polymerization method. The photoluminescence properties of the incorporated pyrene chromophore were studied by using hybrids those were obtained by changing the ratio of inorganic moieties. As compared with organic polymers or a silica glass, the excimer emission of pyrene chromophore increased in the polymer hybrids. The excimer emission can be affected by changing the organic/inorganic ratio or the species of organic polymers. In the case of employing hydrophilic polymers, the excimer emission intensity of pyrene increased. Also, the excimer emission intensity of pyrene increased in the polymer hybrids having low organic polymer content. Furthermore, the sensitivity against oxygen of these excimer emissions in the polymer hybrids was found to be tuned by the organic/inorganic ratio in the polymer hybrids or the oxygen permeability of the organic polymers employed for hybridization.

DOI： 10.1295/polymj.PJ2007221

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Polymer Science, Japan  

DOI： 10.1295/kobunshi.56.118

Other Link： https://jlc.jst.go.jp/DN/JALC/00290843783?from=CiNii

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：English   Publisher：WILEY  

DOI： 10.1002/pola.23936

Language：English   Book type：Scholarly book

Language：Japanese   Book type：Scholarly book

Language：Japanese   Book type：Scholarly book

Language：Japanese   Book type：Scholarly book

Language：Japanese   Book type：Scholarly book

Presentation type：Oral presentation (general)