Simple Functionalization of a Donor Monomer to Enhance Charge Transfer in Porous Polymer Networks for Photocatalytic Hydrogen Evolution.

Porous polymer networks (PPNs) are promising candidates as photocatalysts for hydrogen production. Constructing a donor-acceptor structure is known to be an effective approach for improving photocatalytic activity. However, the process of how a functional group of a monomer can ensure photoexcited charges transfer and improve the hydrogen evolution rate (HER) has not yet been studied on the molecular level. Herein, we design and synthesize two kinds of triazatruxene (TAT)-based PPNs: TATR-PPN with a hexyl (R) group and TAT-PPN without the hexyl group, to understand the relationship between the presence of the functional group and charge transfer. The hexyl group on the TAT unit was found to ensure the transfer of photoexcited electrons from a donor unit to an acceptor unit and endowed the TATR-PPN with stable hydrogen production.

Out-of-Plane Single-Copper-Site Catalysts for Room-Temperature Benzene Oxidation.

Crafting single-atom catalysts (SACs) that possess "just right" modulated electronic and geometric structures, granting accessible active sites for direct room-temperature benzene oxidation is a coveted objective. However, achieving this goal remains a formidable challenge. Here, we introduce an innovative in situ phosphorus-immitting strategy using a new phosphorus source (phosphorus nitride, P3N5) to construct the phosphorus-rich copper (Cu) SACs, designated as Cu/NPC. These catalysts feature locally protruding metal sites on a nitrogen (N)-phosphorus (P)-carbon (C) support (NPC). Rigorous analyses, including X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS), validate the coordinated bonding of nitrogen and phosphorus with atomically dispersed Cu sites on NPC. Crucially, systematic first-principles calculations, coupled with the climbing image nudged-elastic-band (CI-NEB) method, provide a comprehensive understanding of the structure-property-activity relationship of the distorted Cu-N2P2 centers in Cu/NPC for selective oxidation of benzene to phenol production. Interestingly, Cu/NPC has shown more energetically favorable C-H bond activation compared to the benchmark Cu/NC SACs in the direct oxidation of benzene, resulting in outstanding benzene conversion (50.3 %) and phenol selectivity (99.3 %) at room temperature. Furthermore, Cu/NPC achieves a remarkable turnover frequency of 263 h-1 and mass-specific activity of 35.2 mmol g-1 h-1, surpassing the state-of-the-art benzene-to-phenol conversion catalysts to date.

Cobalt-Porphyrin-Based Covalent Organic Frameworks with Donor-Acceptor Units as Photocatalysts for Carbon Dioxide Reduction.

Covalent organic frameworks (COFs) have emerged as a promising platform for photocatalysts. Their crystalline porous nature allows comprehensive mechanistic studies of photocatalysis, which have revealed that their general photophysical parameters, such as light absorption ability, electronic band structure, and charge separation efficiency, can be conveniently tailored by structural modifications. However, further understanding of the relationship between structure-property-activity is required from the viewpoint of charge-carrier transport, because the charge-carrier property is closely related to alleviation of the excitonic effect. In the present study, COFs composed of a fixed cobalt (Co) porphyrin (Por) centered tetraamine as an acceptor unit with differently conjugated di-carbaldehyde based donor units, such as benzodithiophene (BDT), thienothiophene (TT), or phenyl (TA), were synthesized to form Co-Por-BDT, Co-Por-TT, or Co-Por-TA, respectively. Their photocatalytic activity for reducing carbon dioxide into carbon monoxide was in the order of Co-Por-BDT>Co-Por-TT>Co-Por-TA. The results indicated that the excitonic effect, associated with their charge-carrier densities and π-conjugation lengths, was a significant factor in photocatalysis performance.

Olefin-Linked Covalent Organic Frameworks with Electronegative Channels as Cationic Highways for Sustainable Lithium Metal Battery Anodes.

Despite the enormous interest in Li metal as an ideal anode material, the uncontrollable Li dendrite growth and unstable solid electrolyte interphase have plagued its practical application. These limitations can be attributed to the sluggish and uneven Li+ migration towards Li metal surface. Here, we report olefin-linked covalent organic frameworks (COFs) with electronegative channels for facilitating selective Li+ transport. The triazine rings and fluorinated groups of the COFs are introduced as electron-rich sites capable of enhancing salt dissociation and guiding uniform Li+ flux within the channels, resulting in a high Li+ transference number (0.85) and high ionic conductivity (1.78 mS cm-1 ). The COFs are mixed with a polymeric binder to form mixed matrix membranes. These membranes enable reliable Li plating/stripping cyclability over 700 h in Li/Li symmetric cells and stable capacity retention in Li/LiFePO4 cells, demonstrating its potential as a viable cationic highway for accelerating Li+ conduction.

Hexaazatriphenylene-Based Two-Dimensional Conductive Covalent Organic Framework with Anisotropic Charge Transfer.

The development of covalent organic frameworks (COFs) with efficient charge transport is of immense interest for applications in optoelectronic devices. To enhance COF charge transport properties, electroactive building blocks and dopants can be used to induce extended conduction channels. However, understanding their intricate interplay remains challenging. We designed and synthesized a tailor-made COF structure with electroactive hexaazatriphenylene (HAT) core units and planar dioxin (D) linkages, denoted as HD-COF. With the support of theoretical calculations, we found that the HAT units in the HD-COF induce strong, eclipsed π-π stacking. The unique stacking of HAT units and the weak in-plane conjugation of dioxin linkages leads to efficient anisotropic charge transport. We fabricated HD-COF films to minimize the grain boundary effect of bulk COFs, which resulted in enhanced conductivity. As a result, the HD-COF films showed an electrical conductivity as high as 1.25 S cm-1 after doping with tris(4-bromophenyl)ammoniumyl hexachloroantimonate.

Conductive and Ultrastable Covalent Organic Framework/Carbon Hybrid as an Ideal Electrocatalytic Platform.

Developing covalent organic frameworks (COFs) with good electrical conductivity is essential to widen their range of practical applications. Thermal annealing is known to be a facile approach for enhancing conductivity. However, at higher temperatures, most COFs undergo amorphization and/or thermal degradation because of the lack of linker rigidity and physicochemical stability. Here, we report the synthesis of a conductive benzoxazole-linked COF/carbon hybrid material (BCOF-600C) by simple thermal annealing. The fused-aromatic benzoxazole and biphenyl building units endow the resulting COF with excellent physicochemical stability against high temperatures and strong acids/bases. This allows heat treatment to further enhance electrical conductivity with minimal structural alteration. The robust crystalline structure with periodically incorporated nitrogen atoms allowed platinum (Pt) atoms to be atomically integrated into the channel walls of BCOF-600C. The resulting electrocatalyst with well-defined active sites exhibited superior catalytic performance toward hydrogen evolution in acidic media.

Synthesis of Saddle-Shape Octaaminotetraphenylene Octahydrochloride.

Apart from being experimentally and theoretically interesting, tetraphenylene has potential applications in different fields, including supramolecular chemistry, material science, and asymmetric catalysis. Although a wide range of substituted tetraphenylenes have been reported, octaamine-based tetraphenylene derivatives have not been reported because of their instability. Here, stable octaaminotetraphenylene octahydrochloride is synthesized from the bromination of tetraphenylene to octabromotetraphenylene, which is subsequently aminated into octaiminotetraphenylene. Finally, the imino derivative is deprotected to yield octaaminotetraphenylene octahydrochloride.

Converting Unstable Imine-Linked Network into Stable Aromatic Benzoxazole-Linked One via Post-oxidative Cyclization.

Efficiently converting unstable linkages into stable linkages is an important objective in the chemistry of covalent organic frameworks (COFs), because it enhances stability and preserves crystallinity. Here, an unstable imine-linked COF was converted into a stable aromatic benzoxazole-linked COF (BO-COF) via post-oxidative cyclization, based on chemistry used to form fused-aromatic ladder-like rigid-rod polymers. The structure of the porous BO-COF was confirmed by transmission electron microscopy, infrared and solid-state nuclear magnetic resonance spectroscopies, powder X-ray diffraction patterns, and nitrogen adsorption-desorption isotherms. The efficient post-treatment of an unstable reversible COF converted it into a stable irreversible COF, which had significantly improved thermal and chemical stabilities as well as high crystallinity. This strategy can be universally applied for the synthesis of stable fused-aromatic COFs, expanding their practical applications.

Two-dimensional polyaniline (C3N) from carbonized organic single crystals in solid state.

The formation of 2D polyaniline (PANI) has attracted considerable interest due to its expected electronic and optoelectronic properties. Although PANI was discovered over 150 y ago, obtaining an atomically well-defined 2D PANI framework has been a longstanding challenge. Here, we describe the synthesis of 2D PANI via the direct pyrolysis of hexaaminobenzene trihydrochloride single crystals in solid state. The 2D PANI consists of three phenyl rings sharing six nitrogen atoms, and its structural unit has the empirical formula of C3N. The topological and electronic structures of the 2D PANI were revealed by scanning tunneling microscopy and scanning tunneling spectroscopy combined with a first-principle density functional theory calculation. The electronic properties of pristine 2D PANI films (undoped) showed ambipolar behaviors with a Dirac point of -37 V and an average conductivity of 0.72 S/cm. After doping with hydrochloric acid, the conductivity jumped to 1.41 × 10(3) S/cm, which is the highest value for doped PANI reported to date. Although the structure of 2D PANI is analogous to graphene, it contains uniformly distributed nitrogen atoms for multifunctionality; hence, we anticipate that 2D PANI has strong potential, from wet chemistry to device applications, beyond linear PANI and other 2D materials.

A Robust 3D Cage-like Ultramicroporous Network Structure with High Gas-Uptake Capacity.

A three-dimensional (3D) cage-like organic network (3D-CON) structure synthesized by the straightforward condensation of building blocks designed with gas adsorption properties is presented. The 3D-CON can be prepared using an easy but powerful route, which is essential for commercial scale-up. The resulting fused aromatic 3D-CON exhibited a high Brunauer-Emmett-Teller (BET) specific surface area of up to 2247 m2 g-1 . More importantly, the 3D-CON displayed outstanding low pressure hydrogen (H2 , 2.64 wt %, 1.0 bar and 77 K), methane (CH4 , 2.4 wt %, 1.0 bar and 273 K), and carbon dioxide (CO2 , 26.7 wt %, 1.0 bar and 273 K) uptake with a high isosteric heat of adsorption (H2 , 8.10 kJ mol-1 ; CH4 , 18.72 kJ mol-1 ; CO2 , 31.87 kJ mol-1 ). These values are among the best reported for organic networks with high thermal stability (ca. 600 °C).

Direct Synthesis of a Covalent Triazine-Based Framework from Aromatic Amides.

There have been extensive efforts to synthesize crystalline covalent triazine-based frameworks (CTFs) for practical applications and to realize their potential. The phosphorus pentoxide (P2 O5 )-catalyzed direct condensation of aromatic amide instead of aromatic nitrile to form triazine rings. P2 O5 -catalyzed condensation was applied on terephthalamide to construct a covalent triazine-based framework (pCTF-1). This approach yielded highly crystalline pCTF-1 with high specific surface area (2034.1 m2 g-1 ). At low pressure, the pCTF-1 showed high CO2 (21.9 wt % at 273 K) and H2 (1.75 wt % at 77 K) uptake capacities. The direct formation of a triazine-based COF was also confirmed by model reactions, with the P2 O5 -catalyzed condensation reaction of both benzamide and benzonitrile to form 1,3,5-triphenyl-2,4,6-triazine in high yield.

Pharmacokinetics of a telmisartan/rosuvastatin fixed-dose combination: a single-dose, randomized, open-label, 2-period crossover study in healthy Korean subjects.

OBJECTIVE: As hypertension and dyslipidemia are frequent comorbidities, antihypertensive drugs and lipid-lowering agents are often prescribed together for their treatment. Telmisartan and rosuvastatin are widely used together to treat hypertension and dyslipidemia. A combination formulation of these two drugs would improve patient compliance due to ease of dosing. The purpose of this study was to assess bioequivalence of single-dose administration of a newly-developed fixed-dose combination (FDC) tablet containing telmisartan/rosuvastatin 80/20 mg (test treatment) and coadministration of a telmisartan 80-mg tablet and a rosuvastatin 20-mg tablet (reference treatment) in healthy Korean male volunteers. METHODS: This was a single-dose, randomized, open-label, 2-period crossover study enrolling healthy males aged 20 - 50 years with BMI between 18.5 and 25 kg/m2. Each subject received a single dose of the reference and test treatments with a 14-day washout period. Blood sampling was performed at prespecified intervals for up to 72 hours after dosing. Primary pharmacokinetic parameters were Cmax, AUClast, and AUC0-∞ of telmisartan, rosuvastatin, and N-desmethyl rosuvastatin. Bioequivalence was assessed by determining whether the 90% confidence intervals (CIs) of the geometric mean ratios (test treatment/reference treatment) of these parameters were within the standard range of 80% to 125%. Adverse events were monitored via regular interviews with the subjects and by physical examinations. RESULTS: 60 subjects were enrolled and 55 completed the study. The 90% CIs of the geometric mean ratios of Cmax, AUClast, and AUC00-∞ were 0.9262-1.1498, 0.9294-1.0313, and 0.9312-1.0320 for telmisartan, 0.9041-1.0428, 0.9262-1.0085, and 0.9307-1.0094 for rosuvastatin, and 0.8718-1.0022, 0.8901-0.9904, and 0.8872-0.9767 for N-desmethyl rosuvastatin, respectively. There was no statistical difference in the incidence of adverse events (AEs) (all of which were mild or moderate) between the reference and test treatments. CONCLUSIONS: Our findings suggest that the telmisartan/rosuvastatin FDC is bioequivalent to coadministration of separate tablets, and both treatments were safe and well tolerated. Administration of this FDC tablet is expected to improve patient compliance.

Edge-carboxylated graphene nanosheets via ball milling.

Low-cost, high-yield production of graphene nanosheets (GNs) is essential for practical applications. We have achieved high yield of edge-selectively carboxylated graphite (ECG) by a simple ball milling of pristine graphite in the presence of dry ice. The resultant ECG is highly dispersable in various solvents to self-exfoliate into single- and few-layer (≤ 5 layers) GNs. These stable ECG (or GN) dispersions have been used for solution processing, coupled with thermal decarboxylation, to produce large-area GN films for many potential applications ranging from electronic materials to chemical catalysts. The electrical conductivity of a thermally decarboxylated ECG film was found to be as high as 1214 S/cm, which is superior to its GO counterparts. Ball milling can thus provide simple, but efficient and versatile, and eco-friendly (CO(2)-capturing) approaches to low-cost mass production of high-quality GNs for applications where GOs have been exploited and beyond.

Two and three dimensional network polymers for electrocatalysis.

Recently, two and three dimensional network polymers have started to gain traction in the research sphere as scientists look for ways to create materials with more tailored properties. These network polymers show high surface area and specific, sometimes periodic, functionality, providing perfect templates both to host electrocatalytic materials as well as function as electrocatalysts themselves. While doped carbon based materials such as graphene and carbon nanotubes, as well as diamond, have demonstrated their electrocatalytic potential, other network polymers have yet to be synthesized in a manner to optimize their potential. As these polymers are built of a periodic arrangement of appropriately functionalized monomers, an exact arrangement of functional sites should be possible, which combined with potentially high surface areas should lead to very high catalytic activity. This perspective will cover the synthesis and achievements of the mentioned doped carbon materials before taking a look at the strengths, shortcomings, and future goals in electrocatalysis as related to more novel network polymers.

Direct solvothermal synthesis of B/N-doped graphene.

Heteroatom-doping into graphitic networks has been utilized for opening the band gap of graphene. However, boron-doping into the graphitic framework is extremely limited, whereas nitrogen-doping is relatively feasible. Herein, boron/nitrogen co-doped graphene (BCN-graphene) is directly synthesized from the reaction of CCl4 , BBr3 , and N2 in the presence of potassium. The resultant BCN-graphene has boron and nitrogen contents of 2.38 and 2.66 atom %, respectively, and displays good dispersion stability in N-methyl-2-pyrrolidone, allowing for solution casting fabrication of a field-effect transistor. The device displays an on/off ratio of 10.7 with an optical band gap of 3.3 eV. Considering the scalability of the production method and the benefits of solution processability, BCN-graphene has high potential for many practical applications.

Direct Electroplating Ruthenium Precursor on the Surface Oxidized Nickel Foam for Efficient and Stable Bifunctional Alkaline Water Electrolysis.

Water electrolysis to produce hydrogen (H2) using renewable energy is one of the most promising candidates for realizing carbon neutrality, but its reaction kinetics is hindered by sluggish anodic oxygen evolution reaction (OER). Ruthenium (Ru) in its high-valence state (oxide) provides one of the most active OER sites and is less costly, but thermodynamically unstable. The strong interaction between Ru nanoparticles (NPs) and nickel hydroxide (Ni(OH)2) is leveraged to directly form Ru-Ni(OH)2 on the surface of a porous nickel foam (NF) electrode via spontaneous galvanic replacement reaction. The formation of Ru─O─Ni bonds at the interface of the Ru NPs and Ni(OH)2 (Ru-Ni(OH)2) on the surface oxidized NF significantly enhance stability of the Ru-Ni(OH)2/NF electrode. In addition to OER, the catalyst is active enough for the hydrogen evolution reaction (HER). As a result, it is able to deliver overpotentials of 228 and 15 mV to reach 10 mA cm-2 for OER and HER, respectively. An industry-scale evaluation using Ru-Ni(OH)2/NF as both OER and HER electrodes demonstrates a high current density of 1500 mA cm-2 (OER: 410 mV; HER: 240 mV), surpassing commercial RuO2 (OER: 600 mV) and Pt/C based performance (HER: 265 mV).

Large-scale production of edge-selectively functionalized graphene nanoplatelets via ball milling and their use as metal-free electrocatalysts for oxygen reduction reaction.

Edge-selectively functionalized graphene nanoplatelets (EFGnPs) with different functional groups were efficiently prepared simply by dry ball milling graphite in the presence of hydrogen, carbon dioxide, sulfur trioxide, or carbon dioxide/sulfur trioxide mixture. Upon exposure to air moisture, the resultant hydrogen- (HGnP), carboxylic acid- (CGnP), sulfonic acid- (SGnP), and carboxylic acid/sulfonic acid- (CSGnP) functionalized GnPs readily dispersed into various polar solvents, including neutral water. The resultant EFGnPs were then used as electrocatalysts for oxygen reduction reaction (ORR) in an alkaline electrolyte. It was found that the edge polar nature of the newly prepared EFGnPs without heteroatom doping into their basal plane played an important role in regulating the ORR efficiency with the electrocatalytic activity in the order of SGnP > CSGnP > CGnP > HGnP > pristine graphite. More importantly, the sulfur-containing SGnP and CSGnP were found to have a superior ORR performance to commercially available platinum-based electrocatalyst.

Intense Hydrochromic Photon Upconversion from Lead-Free 0D Metal Halides For Water Detection and Information Encryption.

Hydrochromic materials that change their luminescence color upon exposure to moisture have attracted considerable attention owing to their applications in sensing and information encryption. However, the existing materials lack high hydrochromic response and color tunability. This study reports the development of a new and bright 0D Cs3 GdCl6 metal halide as the host for hydrochromic photon upconversion in the form of polycrystals (PCs) and nanocrystals. Lanthanides co-doped cesium gadolinium chloride metal halides exhibit upconversion luminescence (UCL) in the visible-infrared region upon 980 nm laser excitation. In particular, PCs co-doped with Yb3+ and Er3+ exhibit hydrochromic UCL color change from green to red. These hydrochromic properties are quantitatively confirmed through the sensitive detection of water in tetrahydrofuran solvent via UCL color changes. This water-sensing probe exhibits excellent repeatability and is particularly suitable for real-time and long-term water monitoring. Furthermore, the hydrochromic UCL property is exploited for stimuli-responsive information encryption via cyphertexts. These findings will pave the way for the development of new hydrochromic upconverting materials for emerging applications, such as noncontact sensors, anti-counterfeiting, and information encryption.

Effects of Thinning Intensity on Litterfall Production, Soil Chemical Properties, and Fine Root Distribution in Pinus koraiensis Plantation in Republic of Korea.

It is crucial to evaluate the effects of thinning on litterfall production, soil chemical properties, and fine root dynamics when implementing thinning as a silvilcultural technique to enhance tree growth and timber yield in Pinus koraiensis plantations. Thus, we determined the 10-year effects (2007-2017) of different thinning intensities on litterfall production, soil chemical properties, and fine root biomass and necromass within a P. koraiensis plantation in South Korea. The soil chemical parameters and fine root biomass and necromass were also compared across three soil depths (0-10, 10-20, and 20-30 cm). Three thinning treatments were employed: no thinning (CON), light thinning (32% removed, LT), and heavy thinning (64% removed, HT). Results revealed that litterfall was consistent across all thinning treatments, but broadleaf species had considerably higher litterfall production at HT stands than at CON/LT stands. Soil chemical properties, except exchangeable K+, were generally lower at LT stands, particularly at a depth of 20-30 cm soil. After ten years, there was a decrease in fine root biomass and necromass with increasing soil depth. Over 80% of fine roots were found in the upper layer (0-20 cm), while very fine roots (0-1 mm) consisted mainly of 47% pine and 53% other species and were concentrated in the 0-10 cm soil depth in HT. In conclusion, different thinning intensities had diverse effects on the parameters measured within the plantation. Future studies can explore how the effects of thinning intensities on litterfall production, soil chemistry, and fine root dynamics affect species diversity, carbon storage, and understory vegetation in P. koraiensis plantations.

Survey Result for E-labeling Initiatives in Asia.

Under the COVID-19 pandemic, various electronic labeling initiatives have accelerated worldwide in the healthcare and pharmaceutical fields as part of a wider digital transformation [1, 2]. Although there is no universal definition of electronic labeling (e-labeling) globally, it is widely understood that e-labeling refers to the product information that is distributed via electronic means. There are 5 factors to be considered in e-labeling, and these are discussed in this publication. APAC is an industry-driven initiative with 13 R&D-based pharmaceutical associations joining from 11 markets in Asia. e-labeling was discussed as a new topic starting in 2020, and a 22-question survey was conducted in November 2021 to understand the current e-labeling status. The survey results showed that e-labeling initiatives were at different levels of maturity in the Asian region, although most markets have started to discuss e-labeling initiatives. Various challenges exist around e-labeling initiatives due to a variety of different approaches being taken in the region. It would be advisable to develop regional guidance on how to proceed with e-labeling initiatives in the Asian region to have a consistent and efficient approach. The close collaboration between agencies, Health Care Professionals (HCPs), patients, and industry associations is important to move e-labeling initiatives forward in Asia.