Search

Combining a MOF template with simple rubbing methods achieves macroscopic alignment of unprocessable polymer chains.

The acene series, an important class of linearly polycyclic aromatic hydrocarbons, are of interest owing to their unique physicochemical features. With an increase in the number of fused benzene rings, acenes display an evolution of electronic structure and properties. Thus, efforts have been devoted to the synthesis of longer acenes, with dodecacene being the longest acene (12 fused benzene rings) reported to date. However, the formation of polymeric acenes with numerous benzene rings, namely polyacene, has yet to be realized. Herein, we present a methodology for the synthesis of polyacene mediated by a metal–organic framework. Nanoconfined synthesis of precursor polymers in the channels of the metal–organic framework and the subsequent dehydro-aromatization reaction produced polyacene that was overwhelmingly longer than the previously reported acenes. The scalable synthesis of polyacene allowed us to unveil the stability and electronic properties of polyacene, paving the way for their widespread applications in optoelectronic and magnetic devices.

This review highlights recent advances in controlled synthesis of conjugated ladder polymers using templates.

The number of synthetic strategies used to functionalize MOFs with polymers is rapidly growing; this stems from the knowledge that non-native polymeric guests can significantly boost MOF performance in a number of desirable applications. The current work presents a scalable and solid-state method for MOF/polymer composite production. This simple method constitutes mixing a MOF powder, namely, Fe-BTC (BTC = 1,3,5-benzenetricarboxylate), with a biomass-derived solid monomer, 5-hydroxymethylfurfural (HMF), and subsequently heating the solids; the latter promotes both solid-state diffusion of HMF into the MOF and the formation of polymeric humin species with a high density of accessible hydroxyl functionality within the MOF pore. The resulting composite, Fe-BTC/humin, was found to selectively extract Ag+ ions from laundry wastewater. Subsequent reduction of the Ag+ species yields a novel catalyst, Fe-BTC/humin/Ag, that is able to drive the organic transformation of cinnamaldehyde in a highly selective manner. Moreover, the catalyst exhibited recyclability up to five cycles, which is in contrast to the Fe-BTC/Ag catalyst without the humin-based polymer. It is envisioned that MOF/polymer composites that are able to selectively extract precious metals from liquid waste streams can be used for the future production of sustainable catalysts; this work was aimed at demonstrating a proof of concept in this regard. Moreover, this study brings more understanding of the impact that MOFs can have on polymer functionalities. Understanding the polymer structure and how it can be manipulated will help us realize the high degree of future potential of this distinct class of composite materials.

The acene series, an important class of linearly polycyclic aromatic hydrocarbons, are of significant interest owing to their unique physicochemical features. With an increase in the number of fused benzene rings, acenes display an evolution of electronic structure and properties. Thus, tremendous efforts have been devoted to the synthesis of longer acenes, reaching dodecacene being the longest acene (12-fused benzene rings) reported to date. However, the formation of polymeric acenes with numerous benzene rings, namely polyacene (PA), has yet to be realized. Herein, we present a methodology for the synthesis of PA, as a long-sought-after compound, mediated by a metal−organic framework (MOF). Nanoconfined synthesis of precursor polymers in MOF channels and the subsequent dehydro-aromatization reaction produced PA that was overwhelmingly longer than the previously reported acenes. The scalable synthesis of PA could allow us to unveil the stability and electronic properties of PA, paving the way for their widespread applications in both the scientific and industrial fields.

Background An association between uric acid (UA) and cardiovascular diseases, including heart failure (HF), has been reported. However, whether UA is a causal risk factor for HF is controversial. In particular, the prognostic value of lowering UA in patients with HF with preserved ejection fraction (HFpEF) is unclear. Methods and Results We enrolled patients with HFpEF from the PURSUIT‐HFpEF (Prospective Multicenter Observational Study of Patients With Heart Failure With Preserved Ejection Fraction) registry. We investigated whether UA was correlated with the composite events, including all‐cause mortality and HF rehospitalization, in patients with hyperuricemia and HFpEF (UA >7.0 mg/dL). Additionally, we evaluated whether lowering UA for 1 year (≥1.0 mg/dL) in them reduced mortality or HF rehospitalization. We finally analyzed 464 patients with hyperuricemia. In multivariable Cox regression analysis, UA was an independent determinant of composite death and rehospitalization (hazard ratio [HR], 1.15 [95% CI, 1.03–1.27], P =0.015). We divided them into groups with severe and mild hyperuricemia according to median estimated value of serum UA (8.3 mg/dL). Cox proportional hazards models revealed the incidence of all‐cause mortality was significantly higher in the group with severe hyperuricemia than in the group with mild hyperuricemia (HR, 1.73 [95% CI, 1.19–2.25], P =0.004). The incidence of all‐cause mortality was significantly decreased in the group with lowering UA compared with the group with nonlowering UA (HR, 1.71 [95% CI, 1.02–2.86], P =0.041). The incidence of urate‐lowering therapy tended to be higher in the group with lowering UA than in the group with nonlowering UA (34.9% versus 24.6%, P =0.06). Conclusions UA is a predictor for the composite of all‐cause death and HF rehospitalization in patients with hyperuricemia and HFpEF. In these patients, lowering UA, including the use of urate‐lowering therapy, may improve prognosis.

Chiral induction is an emerging topic of interest in various areas of chemistry because of its relationship to the elusive mechanism of spontaneous symmetry breaking in nature. Buckminsterfullerene (C60 ) with the shape of a highly symmetric truncated icosahedron has rarely been referred for chiral induction due to the difficult symmetry breaking. In this work, we demonstrate that a chiral metal-organic framework (MOF) can provide a key field for chiral induction. C60 could be incorporated into the chiral nanochannels of the MOF using an in situ self-assembly strategy. The circular dichroism spectra of the resulting nanocomposites showed an intense chiral signal in the absorption region of C60 . Experimental and theoretical studies showed that this unprecedented chiral induction of C60 was attributed to hybridization of the molecular orbitals through a close association with the pore surface of the MOF. Our method can endow highly symmetric achiral compounds with chirality, paving the new way toward fabrication of novel chiral nanomaterials.

We herein report a case of sudden death in a 20s male who presented with fever 1 week before and with abdominal pain and vomiting 2 days before death. Laboratory findings at the time of death were suspected the onset of fulminant type 1 diabetes accompanied by diabetic ketoacidosis and acute renal failure. A postmortem blood examination at several sites showed elevated levels of glucose and β-hydroxybutyrate, lower levels of C-peptide, insulin, 1,5-anhydroglucitol, and HbA1c of less than 8.7% based on the diagnostic criteria of FT1DM. Furthermore, glucose levels in vitreous humor and cerebrospinal fluid were very high. These results showed reflecting antemortem hyperglycemia. Postmortem serum pancreatic enzyme levels of lipase and elastase 1 were high. Antibodies to insulin, insulinoma-associated antigen-2 (IA-2), and zinc transporter 8 (ZnT8) were negative, while antibodies to glutamic acid decarboxylase (GAD) slightly exceeded the reference range (

Here we report a bio-adhesive porous organic module (Glue COF) composed of hexagonally packed 1D nanopores based on a covalent organic framework. The nanopores are densely decorated with guanidinium ion (Gu+ ) pendants capable of forming salt bridges with oxyanionic species. Glue COF strongly adheres to biopolymers through multivalent salt-bridging interactions with their ubiquitous oxyanionic species. By taking advantage of its strong bio-adhesive nature, we succeeded in creating a gate that possibly opens the nanopores through a selective interaction with a reporter chemical and releases guest molecules. We chose calmodulin (CaM) as a gating component that can stably entrap a loaded guest, sulforhodamine B (SRB), within the nanopores (CaM COF⊃SRB). CaM is known to change its conformation on binding with Ca2+ ions. We confirmed that mixing CaM COF⊃SRB with Ca2+ resulted in the release of SRB from the nanopores, whereas the use of weakly binding Mg2+ ions resulted in a much slower release of SRB.

Three isostructural porous ionic crystals (PICs) based on Keggin-type POMs with different compositions but equal negative charge ([BW12O40]5−, [SiW11NbO40]5−, and [SiW11TaO40]5− ) are synthesized.

As conjugated polymers play crucial roles in advanced nanoscale devices, future applications require a deeper understanding optoelectrical properties of conjugated polymers in low-dimensional assemblies. Confinement of polymer chains in nanoporous materials is a feasible method to control the polymer assemblies because this approach can prevent the entanglement and conformational disorder of polymer chains in the bulk state. The regulated and tailor-made pore characteristics of metal-organic frameworks (MOFs) allow the achievement of precise molecular assemblies in the nanopores, permitting fundamental studies on polymer properties that, until now, have remained elusive.1 Here, we report that the hybridization of MOFs and polythiophene (PTh) provides a great insight into inherent optoelectrical properties of PTh as well as functional nanomaterials for electronics and sensors.2 Controlled assembly of PTh donor and acceptor molecules is a key structure for photovoltaics and photocatalysis. We also demonstrated that unique interfaces between PTh and acceptor molecules, such as fullerene and titanium oxide, mediated by MOFs, enabled remarkable photoelectronic properties superior to conventional PTh systems.3 Other than conjugated polymers, a variety of conjugated materials, including graphene nanoribbons, could be prepared in MOFs, providing distinctly properties to those prepared in the bulk state because of the formation of specific assemblies.4 REFERENCES 1. Chem. Soc. Rev. 2017, 46, 3108. 2. (a) J. Am. Chem. Soc., 2015, 137, 5231. (b) Angew. Chem. Int. Ed., 2016, 55, 708. (c) Polym. Chem., 2017, 8, 5077. (d) Eur. Polym. J., 2018, 109, 162. (e) J. Am. Chem. Soc., 2019, 141, 19565. 3. (a) Nat. Commun., 2018, 9, 1660. (b) J. Phys. Chem. C, 2018, 122, 24182. 4. J. Am. Chem. Soc., 2020 , 142, 5509. Figure 1

Recent developments in controlling polymer assemblies using metal–organic frameworks (MOFs) are covered in this highlight review. The characteristic features of MOFs are their highly tailorable and...

Recently developed coronary angiography with intraprocedural 320-row computed tomography can be performed in a catheterization laboratory (XACT) by injecting contrast medium from a place close to the coronary arteries, thereby requiring a minimal amount of contrast medium. However, its clinical application has not yet been established. This study aimed to evaluate the diagnostic accuracy of XACT angiography with a minimal volume of contrast medium in patients with suspected coronary artery disease (CAD). A total of 167 coronary segments were analyzed in 14 patients (9 males, median age 70 years) with suspected CAD by XACT angiography with 7.5 ml of contrast medium and invasive coronary angiography (ICA) with standard techniques. The segmental-based diagnostic accuracy of XACT angiography in detecting stenosis of ≥ 50% and ≥ 75% and visualized by ICA was good (sensitivity: 74% and 62%, specificity: 99% and 99%, positive predictive value: 93% and 80%, and negative predictive value: 97% and 97%, respectively). These results suggest that XACT angiography with a very low amount of contrast medium may have strong clinical utility for screening coronary arteries in patients with renal dysfunction or undergoing clinical procedures such as pacemaker implantation.

It has been over half a century since polyacrylonitrile (PAN)-based carbon fibers were first developed. However, the mechanism of the carbonization reaction remains largely unknown. Structural evolution of PAN during the preoxidation reaction, a stabilization reaction, is one of the most complicated stages because many chemical reactions, including cyclization, dehydration, and cross-linking reactions, simultaneously take place. Here, we report the stabilization reaction of single PAN chains within the one-dimensional nanochannels of metal–organic frameworks (MOFs) to study an effect of interchain interactions on the stabilization process as well as the structure of the resulting ladder polymer (LP). The stabilization reaction of PAN within the MOFs could suppress the rapid generation of heat that initiates the self-catalyzed reaction and inevitably provokes many side-reactions and scission of PAN chains in the bulk state. Consequently, LP prepared within the MOFs had a more extended conjugated backbone than the bulk condition., Accommodation of polyacrylonitrile in MOFs facilitated and regulated the transformation to ladder polymer in the carbonization process.

Eleven isostructural mesoporous ionic crystals (meso-PICs) are synthesized. The initial activities of the Barbier-Grignard reaction, which is a typical C-C bond formation reaction, catalyzed by the meso-PICs are dependent on the acid dissociation constant of the aqua ions of Mn+ and the types of polyoxometalates, which construct the meso-PICs.

Metal–organic frameworks (MOFs) have recently emerged as a new class of porous materials. Highly ordered and tunable structures of MOFs can serve as a universal platform for controlled polymer synthesis as well as high-precision polymer recognition. In addition, the integration of MOFs and polymers can achieve host–guest synergies, leading to the emergence of intriguing composites with tailored architectures. The integration of MOFs and polymers has provided new aspects for both MOF and polymer chemistry. In this chapter, we highlight recent advances in the hybridization of MOFs and polymers.

Polyoxometalates (POMs) are oxide cluster anions composed of high-valence early transition metals and are widely used as catalysts. Yet base catalysis of POMs remains an ongoing challenge; group V (V, Nb, and Ta) elements form more negatively charged POMs than group VI (Mo and W) elements, and in particular, polyoxoniobates and polyoxotantalates are known to show strong basicity in solution due to the highly negative surface oxygen atoms. Herein, we report for the first time porous ionic crystals (PICs) comprising Nb or Ta. The PICs are composed of Dawson-type Nb/W or Ta/W mixed-addenda POMs with oxo-centered trinuclear CrIII carboxylates and potassium ions as counter cations to control the crystal structure. Among the PICs, those with Nb or Ta tri-substituted POMs exhibit the highest yield (78–82%) and selectivity (99%) towards the Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate (353 K, 6 h), which is a typical base-catalyzed reaction, as reusable solid catalysts, and they can also catalyze the reaction of other active methylene compounds. A detailed investigation into the crystal structures together with DFT calculations and in situ IR spectroscopy with methanol as a basic probe molecule shows that the exposure of [Nb3O13] or [Ta3O13] units with highly negative surface oxygen atoms to the pore surface of PICs is crucial to the catalytic performance. These findings based on the composition–structure–function relationships show that Nb- and Ta-containing PICs can serve as platforms for rational designing of heterogeneous base catalysts.

Here, we report an unprecedented chirality transfer from a metal-organic framework (MOF) to a polymer. In this work, unsubstituted polythiophene (PTh) was prepared in the nanochannels of a chiral MOF. Circular dichroism spectroscopy revealed that nanoconfinement of the polymer chains could endow optically inactive PTh with a chiral nature. The thickness of polymer chain assemblies could be controlled by tuning the loading amount of PTh, which resulted in a drastic change in the chiroptical properties. Note that PTh liberated from the host still exhibited chirality even without the chiral support. Remarkably, the recovered PTh presented high thermal stability of chirality up to 250 °C. Our findings show that the encapsulation of the polymer chains in chiral MOFs is a simple and effective methodology not only to express the chirality of polymers but also to elucidate the inter- and intrachain chirality in polymer assemblies.

A platinum diiodide complex with 9-pentafluorophenyl-9-arsafluorene formed a porous molecular crystal (PMC) or a non-porous molecular crystal (n-PMC), depending on the recrystallization solvents. Vapor exposure can cause reversible crystal-to-crystal transition between the PMC and the n-PMC. The PMC exhibits open-close switching of porosity as well as on-off switching of luminescence.

Polyoxometalate based solids are promising candidates of proton-conducting solid electrolytes. In this work, a Preyssler-type polyoxometalate is crystallized with potassium ions and poly(allylamine), which is also a good proton conductor, from aqueous solutions. Here we show that the hygroscopicity induced low durability of polyoxometalate and poly(allylamine) can be circumvented by the electrostatic interaction between the polyoxometalate and protonated amine moieties in the solid state. Crystalline compounds are synthesized with poly(allylamine) of different average molecular weights, and all compounds achieve proton conductivities of 10−2 S cm−1 under mild-humidity and low-temperature conditions. Spectroscopic studies reveal that the side-chain mobility of poly(allylamine) and hydrogen-bonding network rearrangement contribute to the proton conduction of compounds with poly(allylamine) of low and high average molecular weights, respectively. While numbers of proton-conducting amorphous polyoxometalate-polymer composites are reported previously, these results show both structure-property relationship and high functionality in crystalline composites. Polyoxometalate based solids are promising candidates for proton-conducting electrolytes but their low durability and low proton conductivities remains an on-going challenge. Here the authors describe the preparation of polyoxometalate-based solids with much improved stability and proton conductivities.

Films consisting of surface-anchored metal-organic frameworks (SURMOFs) which are prepared by layer-by-layer deposition techniques can be used as highly oriented crystalline template structures for oligomerization processes. Herein, SURMOF films of Zn(bdc) (1) and, Cu(bpdc) (2) were prepared, which consist of lamellar ordered 2D MOF sheets forming 1D channels as the host structures for oligomerization of terthiophene (Tth) and, 3,4-ethylenedioxythiophene (EDOT), respectively. After SURMOF preparation, the pores were filled either with Tth or EDOT and the oligomerization was initiated by oxidizing agents, such as I2 and FeCl3. Using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-ToF/MS), the short chains of polyterthiophene (PTth) and poly(3,4-ethylenedioxythiophene) (PEDOT) were characterized. FT-IR and Raman spectroscopy further confirmed the presence of oligomers inside the pores of the SURMOFs. Using the SURMOF thin films as template, a homogeneously distributed conductive MOF-PEDOT composite coating can be achieved, with potential applications in optoelectronics.

Synthesis of a metal–organic framework by plasma in liquid was demonstrated with HKUST-1 as an example. HKUST-1 synthesized by this method contains a higher amount of monovalent copper ions than that synthesized by other conventional methods. The enhanced water stability was also confirmed.

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.

It is essential for the design and optimization of optoelectrical devices to control the heterointerfacial structures of electron-donor and -acceptor materials at the molecular level because it is here that critical photophysical processes occur. In the present study, we have demonstrated that the accommodation of polythiophene and fullerene without any peripheries in one-dimensional nanochannels of a porous coordination polymer (PCP) enabled selective formation of end-on orientation relative to polythiophene–fullerene interfaces. We studied the charge-carrier dynamics of the one-dimensional assemblies of polythiophene and fullerene confined in the PCP. It is noteworthy that a long-lived charge-separated state arises uniquely in the end-on orientation. Theoretical analysis showed a small electron coupling between polythiophene and fullerene in the end-on orientation, suppressing charge recombination and prolonging the charge-carrier lifetime.

Four isostructural coordination polymer crystals having different metal ions were synthesized and studied for ball milling-induced glass formation. Distinct glass formation was discussed from crystal structures. Doping of molecules for CP glass during the milling was demonstrated, and it resulted in tunable glass properties (Tg and Tc) and enhancement of anhydrous H+ conductivity.

This short review focuses on recent developments in polymerization reactions using metal-organic frameworks (MOFs). MOFs are crystalline porous materials that are able to tune their frameworks, enabling their use as promising media for polymerization. The precise design of the MOF structure is key to controlling polymerizations, allowing for the regulation of not only primary but also higher-order structures.

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.

Metal-organic frameworks (MOFs) have received much attention because of their attractive properties. They show great potential applications in many fields. An emerging trend in MOF research is hybridization with flexible materials, which is the subject of this review. Polymers possess a variety of unique attributes, such as softness, thermal and chemical stability, and optoelectrical properties that can be integrated with MOFs to make hybrids with sophisticated architectures. Hybridization of MOFs and polymers is producing new and versatile materials that exhibit peculiar properties hard to realize with the individual components. This review article focuses on the methodology for hybridization of MOFs and polymers, as well as the intriguing functions of hybrid materials.

Exploration of molecular functions and material properties based on the control of chirality would be a scientifically elegant approach. Here, the fabrication and function of chiral-featured materials from both chiral and achiral components using a supramolecular nanoarchitectonics concept are discussed. The contents are classified in to three topics: i) chiral nanoarchitectonics of rather general molecular assemblies; ii) chiral nanoarchitectonics of metal-organic frameworks (MOFs); iii) chiral nanoarchitectonics in liquid crystals. MOF structures are based on nanoscopically well-defined coordinations, while mesoscopic orientations of liquid-crystalline phases are often flexibly altered. Discussion on the effects and features in these representative materials systems with totally different natures reveals the universal importance of supramolecular chiral nanoarchitectonics. Amplification of chiral molecular information from molecules to materials-level structures and the creation of chirality from achiral components upon temporal statistic fluctuations are universal, regardless of the nature of the assemblies. These features are thus surely advantageous characteristics for a wide range of applications.

The tailor-made nanospaces of porous coordination polymers (PCPs) allow us to control the assembly structures of guest species. Here, we report the accommodation of anthracene (ANT) in PCP nanochannels to study the effect of pore shape and surface environment on its assemblies. ANT forms herringbone structures in the bulk state. In contrast, the accommodation of ANT in the square nanopores formed π-stacked structure, resulting in a drastic change in the emission properties.