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The mechanism of the aza-aldol reaction between boron aza-enolate and benzaldehyde is investigated by using density functional theory calculations. The result shows that the syn - E isomer is preferentially formed, consistent with experimental observations. The six-membered ring transition state (TS) with the boat form leads to the E isomer, while the more unstable chair TS does to the Z isomer. The preference of the syn isomer is determined by the interactions between the substituents of aza-enolate and benzaldehyde. Structural distortion and intrinsic reaction coordinate analyses of simplified model systems provide insights into the origin of the relative stability of the rate-determining TS with boat and chair forms. The boat TS is an early TS; thus, minimal structural distortions of the reactant are required to reach this TS. The Lewis pair interactions between the boron and imine groups during B-N elimination also influenced the relative stability of the TSs. This interaction involves the nitrogen lone pair in the boat TS, while the π(N═C) orbital is involved in the chair TS. The Lewis pair with the lone pair stabilizes the TS more than that with the π orbital. The boron aza-enolate with 9-BBN generates an ate complex and forms C-C bonds sequentially, whereas that with Bpin does not generate an ate complex and exhibits the concerted formation of B-O and C-C bonds. Thus, the higher electrophilicity of boron such as 9-BBN enhances the reactivity by facilitating the formation of the ate complex. A reaction design is proposed to reverse the syn / anti selectivity. Proof-of-concept DFT calculations suggested that the modification of the imine group would change the relative stability of the boat/chair TSs and give the anti -product.

A photoinduced copper-catalyzed enantioselective conjugate addition of acylsilanes has been developed. The conjugate acylation of α,β-unsaturated ketones and aldehydes was promoted by a copper(I)/chiral NHC catalyst under visible-light irradiation for synthesizing various 2-substituted 1,4-dicarbonyl compounds in enantioenriched forms. Mechanistic studies combining experiments and quantum chemical calculations indicated a reaction mechanism involving copper-to-acyl charge transfer (i.e., metal-to-ligand charge transfer (MLCT)) excitation of an alkene-bound acylcopper complex. The MLCT excitation is followed by an electronical and geometrical change to generate a β-radical-C-enolate-Cu(II)-acyl complex with an acyl radical character, which undergoes facile C-C bond formation in the copper coordination sphere, affording the 1,4-conjugate addition product., (© 2024 Wiley‐VCH GmbH.)

Metal nanoclusters (NCs) have unique properties because of their small size, which makes them useful as catalysts in reactions like cross-coupling. Pd-catalyzed oxidative amination, which involves dehydrogenative C-N bond formation, uses Pd complexes as the active species. It is known that the catalytic conditions involve the formation of Pd(0) species from Pd NCs, but the precise role of Pd NCs in the transformations has not been established. In this study, we investigated the characteristic properties of Pd NCs in oxidative amination of 1,3-dienes. The reaction achieved direct amination of commercially accessible 1,3-dienes with secondary aromatic amines, providing a variety of nitrogen containing 1,3-dienes. The compound was applicable to radical polymerization to provide the nitrogen-fabricated 1,3-diene-based polymer, which exhibited a different thermal stability compared to aliphatic nitrogen-fabricated diene polymers. In addition to the synthetic utility, by combining X-ray absorption fine structure and small-angle X-ray scattering analysis, we revealed amines and 1,3-dienes affected metal leaching from the Pd nanoparticles and stabilization of Pd NCs in the catalytic reaction. Additionally, DFT calculation suggested that the catalytic intermediate contained multiple adjacent Pd atoms and was responsible for formation of an σ-allylic intermediate that is difficult to form with the use of Pd complexes. These results could be used to understand the underlying phenomenon in the oxidative coupling reaction and develop Pd NCs-based dehydrogenation.

As the sizes of noble metal catalysts, such as platinum, have been successfully minimized, fundamental insights into the electronic properties of metal sub-nanoclusters are increasingly sought for optimizing their catalytic performance. However, it is difficult to rationalize the catalytic activities of metal sub-nanoclusters owing to their more complex electronic structure compared with those of small molecules and bulky solids. In this study, the adsorption of molecular oxygen on a Pt 13 sub-nanocluster supported on a graphene layer was analyzed using density functional theory. Unlike bulk Pt, the Pt 13 sub-nanocluster has multiple adsorption sites, and the adsorption energy depends strongly on the type of adsorption site. The O 2 adsorption energy does not correlate with the transferred charge between O 2 and the Pt 13 moiety; therefore, to elucidate the differences in the adsorption sites, we propose an original approach for analyzing the electronic structure change in metal sub-nanoclusters caused by molecular adsorption. Our analysis of the integrated local density of state (LDOS) revealed that O 2 adsorption on the Pt 13 sub-nanocluster has a distinct feature, different from that on a smaller Pt 2 cluster or rather a larger Pt slab. The change in the electronic structure of the Pt 13 moiety was primarily observed near the Fermi level, different from that of the Pt slab whose DOS was distributed over a wide energy range. Furthermore, the change in the integrated LDOS correlated well with the O 2 adsorption energy on the Pt 13 sub-nanocluster.

During the hydrogenation of CO 2 to methanol over mixed-oxide catalysts, the strong adsorption of CO 2 and formate poses a barrier for H 2 dissociation, limiting methanol selectivity and productivity. Here we show that by using Co-containing dual-atom oxide catalysts, the poisoning effect can be countered by separating the site for H 2 dissociation and the adsorption of intermediates. We synthesized a Co- and In-doped ZrO 2 catalyst (Co-In-ZrO 2 ) containing atomically dispersed Co and In species. Catalyst characterization showed that Co and In atoms were atomically dispersed and were in proximity to each other owing to a random distribution. During the CO 2 hydrogenation reaction, the Co atom was responsible for the adsorption of CO 2 and formate species, while the nearby In atoms promoted the hydrogenation of adsorbed intermediates. The cooperative effect increased the methanol selectivity to 86% over the dual-atom catalyst, and methanol productivity increased 2-fold in comparison to single-atom catalysts. This cooperative effect was extended to Co-Zn and Co-Ga doped ZrO 2 catalysts. This work presents a different approach to designing mixed-oxide catalysts for CO 2 hydrogenation based on the preferential adsorption of substrates and intermediates instead of promoting H 2 dissociation to mitigate the poisonous effects of substrates and intermediates., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Single molecule magnets (SMMs) have been a promising material for next-generation high-density information storage and molecular spintronics. N 2 3- -bridged dilanthanide complexes, {[(Me 3 Si) 2 N] 2 Ln(THF)(μ-η 2 :η 2 -N 2 )(THF)Ln[(Me 3 Si) 2 N] 2 } 1- , exhibit high blocking temperatures and have been one of the promising candidates for future application. Rational understanding should be established between the magnetic properties and electronic structure. However, the theoretical study is still challenging due to the complexities in their electronic structures. Here, we theoretically studied the magnetic susceptibility of dilanthanide SMMs based on the state-of-the-art multistate-complete active space self-consistent field and perturbation theory at the second order and restricted active space state interaction with spin-orbit coupling calculations. Temperature dependence of the magnetic susceptibility (χ m T - T curve) was quantitatively reproduced by the theoretical calculations. The complexities in the electronic states of these dilanthanide complexes originate from significantly strong static electron correlations in the lanthanide 4f and N 2 π* orbitals and the SOC effect. The temperature dependence of the magnetic susceptibility results from the energy levels and magnetic properties of the low-lying excited state. The χ m T values below 50 K are dominated by the ground state, while thermal distribution in the low-lying excited state affects the χ m T values over 50 K. Saturation magnetization at low temperatures was also evaluated, and the result agrees with the experimental observation.

The reaction mechanism of ethylene (ET) polymerization catalyzed by the phenoxy-imine (FI) ligands using DFT calculations was studied. Among five possible isomers, isomer A which has an octahedral geometry and a (cis-N/trans-O/cis-Cl) arrangement is the most stable pre-reaction Ti-FI dichloride complex. The isomer A can be activated by MAO to form the active catalyst and the active form was used for the study of the mechanism for Ti-FI. The second ethylene insertion was found to be the rate-determining step of the catalyzed ethylene polymerization. To examine the effect of group IV B transition metals (M = Ti, Zr, Hf) substitutions, calculated activation energies at the rate-determining step (E a RDS ) were compared, where values of E a RDS of Zr < Hf < Ti agree with experiments. Moreover, we examined the effect of substitution on (O, X) ligands of the Ti-phenoxy-imine (Ti-1) based catalyst. The results revealed that E a RDS of (O, N) > (O, O) > (O, P) > O, S). Hence, the (O, S) ligand has the highest potential to improve the catalytic activity of the Ti-FI catalyst. We also found the activation energy to be related to the Ti-X distance. In addition, a novel Ni-based FI catalyst was investigated. The results indicated that the nickel (II) complex based on the phenoxy-imine (O, N) ligand in the square-planar geometry is more active than in the octahedral geometry. This work provides fundamental insights into the reaction mechanism of M - FI catalysts which can be used for the design and development of M - FI catalysts for ET polymerization., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Surface intermediate species and oxygen vacancy-assisted mechanism over CeO 2 catalyst in the direct dimethyl carbonate (DMC) synthesis from carbon dioxide and methanol are suggested by means of transient spectroscopic methodologies in conjunction with multivariate spectral analysis. How the two reactants, i.e. CO 2 and methanol, interact with the CeO 2 surface and how they form decisive surface intermediates leading to DMC are unraveled by DFT-based molecular dynamics simulation by precise statistical sampling of various configurations of surface states and intermediates. The atomistic simulations and uncovered stability of different intermediate states perfectly explain the unique DMC formation profile experimentally observed upon transient operations, strongly supporting the proposed oxygen vacancy-assisted reaction mechanism., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Dynamic behavior of intermediate adsorbates, such as diffusion, spillover, and reverse spillover, has a strong influence on the catalytic performance in oxide-supported metal catalysts. However, it is challenging to elucidate how the intermediate adsorbates move on the catalyst surface and find active sites to give the corresponding products. In this study, the effect of the dynamic behavior of methoxy intermediate on methanol decomposition on a Pt/TiO 2 (110) surface has been clarified by combination of scanning tunneling microscopy (STM), temperature-programmed desorption (TPD), and density functional theory (DFT) calculations. The methoxy intermediates were formed by the dissociative adsorption of methanol molecules on Pt nanoparticles at room temperature followed by spillover to the TiO 2 (110) support surface. TPD results showed that the methoxy intermediates were thermally decomposed at >350 K on the Pt sites to produce CO (dehydrogenation) and CH 4 (C-O bond scission). A decrease of the Pt nanoparticle density lowered the activity for the decomposition reaction and increased the selectivity toward CH 4 , which indicates that the reaction is controlled by diffusion and reverse spillover of the methoxy intermediates. Time-lapse STM imaging and DFT calculations revealed that the methoxy intermediates migrate on the five-fold coordinated Ti (Ti 5c ) sites along the [001] or [ 1 1 ¯ 0 ] direction with the aid of hydrogen adatoms bonded to the bridging oxygens (O br ) and can move over the entire surface to seek and find active Pt sites. This work offers an in-depth understanding of the important role of intermediate adsorbate migration in the control of the catalytic performance in oxide-supported metal catalysts.

Radical cations show a unique reactivity that is fundamentally different from that of conventional cations and have thus attracted considerable attention as alternative cationic intermediates for novel types of organic reactions. However, asymmetric catalysis to promote enantioselective radical cation reactions remains a major challenge in contemporary organic synthesis. Here, we report that the judicious design of an ion pair consisting of a radical cation and a chiral counteranion induces an excellent level of enantioselectivity. This strategy was applied to enantio-, diastereo-, and regioselective [2 + 2] cycloadditions, as well as enantio-, diastereo-, and regioselective [4 + 2] cycloadditions, by using chiral iron(III) photoredox catalysis. We anticipate that this strategy has the potential to expand the use of several mature chiral anions to develop numerous unprecedented enantioselective radical cation reactions.

Dirhodium complexes bearing bulky carboxylate ligands are synthesized and characterized. The steric bulk of carboxylate ligands could affect the reaction selectivity in Rh-catalyzed intramolecular reactions: Rh catalysts with bulky carboxylate ligands provided five-membered ring products preferentially via the insertion into a carbon-hydrogen bond. Meanwhile, six-membered ring products were obtained using conventional Rh catalysts via the insertion of a carbon-carbon double bond., (© 2023 Wiley-VCH GmbH.)

Inverse molecular design allows the optimization of molecules in chemical space and is promising for accelerating the development of functional molecules and materials. To design realistic molecules, it is necessary to consider geometric stability during optimization. In this work, we introduce an inverse design method that optimizes molecular properties by changing the chemical composition in the equilibrium geometry. The optimization algorithm of our recently developed molecular design method has been modified to allow molecular design for general properties at a low computational cost. The proposed method is based on quantum alchemy and does not require empirical data. We demonstrate the applicability and limitations of the present method in the optimization of the electric dipole moment and atomization energy in small chemical spaces for (BF, CO), (N 2 , CO), BN-doped benzene derivatives, and BN-doped butane derivatives. It was found that the optimality criteria scheme adopted for updating the molecular species yields faster convergence of the optimization and requires a less computational cost. Moreover, we also investigate and discuss the applicability of quantum alchemy to the electric dipole moment.

The electric field (EF) effect on hydrogen or proton transfer (PT) via hydroxyl groups on an anatase TiO 2 (101) surface is examined using first-principles density functional theory and the modern theory of polarization. This study focuses on unidirectional surface PT caused by external EFs at various orientations toward the surface. The preferred PT pathway can change depending on the magnitude and direction of the EF. Detailed analysis reveals that the variation in the energy profile with the EF is significantly different from that determined by the classical electric work of an EF carrying a point charge. The EF effect on the energy profile of the PT is governed by the rearrangement of the chemical bond network at the interface between the water molecules and the surface.

Background: We investigated the efficacy and safety of twice-daily bilayer sustained-release tramadol hydrochloride tablets (35% immediate-release; 65% sustained-release) in patients with postherpetic neuralgia., Methods: This was a Phase III treatment-withdrawal study with 1-4-week dose-escalation, 1-week fixed-dose, and 4-week randomized, double-blind, placebo-controlled withdrawal periods performed at 43 medical institutions in Japan. Patients aged ≥20 years, ≥3 months after the onset of herpes zoster with localized, persistent pain despite fixed-dose analgesics for ≥2 weeks before enrollment were eligible. Patients started tramadol at 100 mg/day and its dose escalated to a maximum of 400 mg/day to achieve a reduction in their Numeric Rating Scale (NRS) for pain of ≥2 points. Eligible patients were randomized to continue tramadol or switched to placebo for 4 weeks (double-blind period). Patients were withdrawn due to inadequate analgesia (NRS deteriorated on ≥2 consecutive days) or their request., Results: Overall, 252 patients started tramadol and 173 were randomized (tramadol: 85; placebo: 88). Tramadol was superior to placebo for the primary endpoint (time from randomization to an inadequate analgesic effect) with log-rank test p = 0.0005. The hazard ratio was 0.353 (95% confidence interval 0.190-0.657) in favor of tramadol and fewer patients in the tramadol group experienced inadequate analgesic effects (16.9% vs. 39.8%). Adverse events in ≥10% of patients in the open-label period were constipation (43.8%), nausea (34.9%), somnolence (18.5%), and dizziness (11.6%). The frequencies of adverse events in the double-blind period were similar in both groups., Conclusion: Sustained-release tramadol tablets with an immediate-release component are effective and well tolerated for managing postherpetic neuralgia., (© 2022 The Authors. Pain Practice published by Wiley Periodicals LLC on behalf of World Institute of Pain.)

Given the industrial importance of (meth)acrylate esters, various groups have devoted considerable effort to investigating their chemoselective transesterification. In 2021, we developed magnesium(ii) and sodium(i) complexes derived from 2,6-di- tert -butyl- p -cresol (BHT-H) as chemoselective catalysts for the transesterification of methyl acrylate (MA) and methyl methacrylate (MMA), respectively. Based on our results, we report the discovery of magnesium(ii) and sodium(i) salts derived from 6,6'-(propane-2,2'-diyl)bis(2,4-di- tert -butylphenol) (PBTP-H 2 ), i.e. Mg(PBTP) and Na 2 (PBTP), which are 41 and 81 times more effective catalysts than Mg(BHT) 2 and Na(BHT) for the transesterification of MA and MMA, respectively. These new catalysts are highly effective across an extensive range of alcohols, including primary and secondary alcohols, diols, and triols. Overall, this efficient transesterification technology can be expected to find practical applications in industrial process chemistry., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

BPh 3 catalyzes the N-methylation of secondary amines and the C-methylenation (methylene-bridge formation between aromatic rings) of N,N-dimethylanilines or 1-methylindoles in the presence of CO 2 and PhSiH 3 ; these reactions proceed at 30-40 °C under solvent-free conditions. In contrast, B(C 6 F 5 ) 3 shows little or no activity. 11 B NMR spectra suggested the generation of [HBPh 3 ] - . The detailed mechanism of the BPh 3 -catalyzed N-methylation of N-methylaniline (1) with CO 2 and PhSiH 3 was studied by using DFT calculations. BPh 3 promotes the conversion of two substrates (N-methylaniline and CO 2 ) into a zwitterionic carbamate to give three-component species [Ph(Me)(H)N + CO 2 - ⋅⋅⋅BPh 3 ]. The carbamate and BPh 3 act as the nucleophile and Lewis acid, respectively, for the activation of PhSiH 3 to generate [HBPh 3 ] - , which is used to produce key CO 2 -derived species, such as silyl formate and bis(silyl)acetal, essential for the N-methylation of 1. DFT calculations also suggested other mechanisms involving water for the generation of [HBPh 3 ] - species., (© 2022 Wiley-VCH GmbH.)

Photosensitization of organometallics is a privileged strategy that enables challenging transformations in transition-metal catalysis. However, the usefulness of such photocatalyst-induced energy transfer has remained opaque in iron-catalyzed reactions despite the intriguing prospects of iron catalysis in synthetic chemistry. Herein, we demonstrate the use of iron/photosensitizer-cocatalyzed cycloaddition to synthesize polyarylpyridines and azafluoranthenes, which have been scarcely accessible using the established iron-catalyzed protocols. Mechanistic studies indicate that triplet energy transfer from the photocatalyst to a ferracyclic intermediate facilitates the thermally demanding nitrile insertion and accounts for the distinct reactivity of the hybrid system. This study thus provides the first demonstration of the role of photosensitization in overcoming the limitations of iron catalysis.

To elucidate the reaction mechanism and the origin of the enantioselectivity of the asymmetric dehydrative cyclization of allyl alcohol to cyclic ether catalyzed by a Cp-ruthenium complex and a chiral pyridinecarboxylic acid, ( R )-X-Naph-PyCOOH, density functional theory (DFT) calculations were performed. According to the DFT calculations, the rate-determining step is the dehydrative σ-allyl formation step with Δ G ‡ = 18.1 kcal mol -1 at 80 °C. This agrees well with the experimental data (Δ G ‡ = 19.01 kcal mol -1 at 80 °C). The DFT result showed that both hydrogen and halogen bonds play a key role in the high enantioselectivity by facilitating the major R , S Ru -catalyzed reaction pathway via a σ-allyl Ru intermediate to generate the major ( S )-product. In contrast, the reaction is sluggish in the presence of the diastereomeric R , R Ru catalyst with an apparent activation energy of 33.1 kcal mol -1 ; the minor ( R )-product is formed via a typical π-allyl Ru intermediate and via a minor pathway for the cyclization step. In addition, the calculated activation Gibbs free energies, 14.4 kcal mol -1 for I < 16.8 kcal mol -1 for Br < 18.1 kcal mol -1 for Cl, reproduced the observed halogen-dependent reactivity with the ( R )-X-Naph-PyCOOH ligands. The origin of the halogen trend was clarified by a structural decomposition analysis.

The design of functional molecules is regarded as searching for molecules with desired functionalities in chemical space populated by candidate molecules. Considering the geometric stability of molecules during the search process is crucial for designing realistic molecules. Here, we propose a method for designing functional molecules by exploring chemical space while explicitly accounting for geometric stability based on computational quantum alchemy. The proposed design method allows the simultaneous prediction of functional molecule in the equilibrium structure and its target desired property in an inverse design fashion without preparing the molecular geometries and performing brute-force screening. The applicability of the design method is proven by obtaining molecules with the desired atomization and electronic energies in various chemical spaces: (BF, CO), (CH 4 , NH 3 ), 18 BN-doped benzene derivatives, and 3.1 × 10 5 BN-doped phenanthrene derivatives.

Background: We evaluated the association of prostate volume (PV) with the efficacy and safety of transurethral enucleation with bipolar energy (TUEB) for treatment of benign prostatic hyperplasia (BPH)., Methods: We retrospectively evaluated data from 180 patients with symptomatic BPH who underwent TUEB between 2008 and 2015. Efficacy was assessed by perioperative changes in international prostate symptom score (IPSS), Quality of Life Score (QOLS), maximum flow rate on uroflowmetry (Qmax), and serum prostate-specific antigen level (PSA), which were recorded at 3 months postoperatively. Safety was assessed by perioperative incidence of adverse events (AEs). AEs were recorded up to 2 years after surgery. Patients were divided into two groups based on PV as the standard group (SG; PV < 80 mL) and large group (LG; PV ≥ 80 mL)., Results: A total of 132 (73%) patients were grouped as the SG, and 48 (27%) were grouped as the LG. No significant differences between the groups were observed in the preoperative variables age, IPSS, and QOLS. However, the LG had a significantly larger PV and higher serum PSA levels. Analysis of surgical outcomes revealed that postoperative changes in IPSS, QOLS, Qmax, serum PSA, serum sodium, and hemoglobin levels did not differ significantly between groups. However, LG had a significantly longer operative time and heavier specimen weight. The rates of early complications, including hyponatremia and blood transfusion, and late complications after surgery did not differ between the groups., Conclusion: The present findings suggest that TUEB is safe and effective for treatment of BPH, regardless of PV.

Helically twisted conductive nanocarbon materials are applicable to optoelectronic and electromagnetic molecular devices working on the nanometer scale. Herein, we report the synthesis of per-peri-perbenzo[5]- and [9]helicenes in addition to previously reported π-extended [7]helicene. The homogeneously π-extended helicenes can be regarded as helically fused oligo-phenanthrenes. The HOMO-LUMO gap decreased significantly from 2.14 to 1.15 eV with increasing helical length, suggesting the large effective conjugation length (ECL) of the π-extended helical framework. The large ECL of π-extended helicenes is attributed to the large orbital interactions between the phenanthrene subunits at the 9- and 10-positions, which form a polyene-like electronic structure. Based on the experimental results and DFT calculations, the ultrafast decay dynamics on the sub-picosecond timescale were attributed to the low-lying conical intersection., (© 2022. The Author(s).)

B7-H3 is overexpressed in various solid tumors and has been considered as an attractive target for cancer therapy. Here, we report the development of DS-7300a, a novel B7-H3-targeting antibody-drug conjugate with a potent DNA topoisomerase I inhibitor, and its in vitro profile, pharmacokinetic profiles, safety profiles, and in vivo antitumor activities in nonclinical species. The target specificity and species cross-reactivity of DS-7300a were assessed. Its pharmacologic activities were evaluated in several human cancer cell lines in vitro and xenograft mouse models, including patient-derived xenograft (PDX) mouse models in vivo. Pharmacokinetics was investigated in cynomolgus monkeys. Safety profiles in rats and cynomolgus monkeys were also assessed. DS-7300a specifically bound to B7-H3 and inhibited the growth of B7-H3-expressing cancer cells, but not that of B7-H3-negative cancer cells, in vitro. Additionally, treatment with DS-7300a and DXd induced phosphorylated checkpoint kinase 1, a DNA damage marker, and cleaved PARP, an apoptosis marker, in cancer cells. Moreover, DS-7300a demonstrated potent in vivo antitumor activities in high-B7-H3 tumor xenograft models, including various tumor types of high-B7-H3 PDX models. Furthermore, DS-7300a was stable in circulation with acceptable pharmacokinetic profiles in monkeys, and well tolerated in rats and monkeys. DS-7300a exerted potent antitumor activities against B7-H3-expressing tumors in in vitro and in vivo models, including PDX mouse models, and showed acceptable pharmacokinetic and safety profiles in nonclinical species. Therefore, DS-7300a may be effective in treating patients with B7-H3-expressing solid tumors in a clinical setting., (©2022 The Authors; Published by the American Association for Cancer Research.)

A compact inertial electrostatic confinement (IEC) fusion neutron source was developed. Imaging tests using the cylindrical IEC neutron source were conducted with the indirect imaging plate (IP) method using dysprosium foil and an imaging plate. An array of B 4 C powder contained in a stainless-steel blade and Cd pins was successfully imaged. To calculate thermal neutron flux of the device, we tested multiple types of IP and IP scanners with the indirect IP method to create a calibration curve, and it was confirmed that dental IP scanners, which are more widely used than industrial ones, can be applied to the indirect IP method.

We report a visible-light-induced copper-catalyzed highly enantioselective umpolung allylic acylation reaction with acylsilanes as acyl anion equivalents. Triplet-quenching experiments and DFT calculations supported our reaction design, which is based on copper-to-acyl metal-to-ligand charge transfer (MLCT) photoexcitation that generates a charge-separated triplet state as a highly reactive intermediate. According to the calculations, the allylic phosphate substrate in the excited state undergoes novel molecular activation into an allylic radical weakly bound to the copper complex. The allyl radical fragment undergoes copper-mediated regio- and stereocontrolled coupling with the acyl group under the influence of the chiral N-heterocyclic carbene ligand.

We focused on identifying a catalytic active site structure at the atomic level and elucidating the mechanism at the elementary reaction level of liquid-phase organic reactions with a heterogeneous catalyst. In this study, we experimentally and computationally investigated efficient C-H bond activation for the selective aerobic α,β-dehydrogenation of saturated ketones by using a Pd-Au bimetallic nanoparticle catalyst supported on CeO 2 (Pd/Au/CeO 2 ) as a case study. Detailed characterization of the catalyst with various observation methods revealed that bimetallic nanoparticles formed on the CeO 2 support with an average size of about 2.5 nm and comprised a Au nanoparticle core and PdO nanospecies dispersed on the core. The formation mechanism of the nanoparticles was clarified through using several CeO 2 -supported controlled catalysts. Activity tests and detailed characterizations demonstrated that the dehydrogenation activity increased with the coordination numbers of Pd-O species in the presence of Au(0) species. Such experimental evidence suggests that a Pd(II)-(μ-O)-Au(0) structure is the true active site for this reaction. Based on density functional theory calculations using a suitable Pd 1 O 2 Au 12 cluster model with the Pd(II)-(μ-O)-Au(0) structure, we propose a C-H bond activation mechanism via concerted catalysis in which the Pd atom acts as a Lewis acid and the adjacent μ-oxo species acts as a Brønsted base simultaneously. The calculated results reproduced the experimental results for the selective formation of 2-cyclohexen-1-one from cyclohexanone without forming phenol, the regioselectivity of the reaction, the turnover-limiting step, and the activation energy., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Chemists have designed strategies that trigger the conformational isomerization of molecules in response to external stimuli, which can be further applied to regulate the complexation between Lewis acids and bases. We have recently developed a system in which frustrated carbene-borane pairs are revived from shelf-stable but external-stimuli-responsive carbene-borane adducts comprised of N-phosphine-oxide-substituted imidazolylidenes (PoxIms) and triarylboranes. Herein, we report the detailed mechanism on this revival process. A thermally induced borane-transfer process from the carbene carbon atom to the N-phosphinoyl oxygen atom initiates the transformation of the carbene-borane adduct. Subsequent conformational isomerization via the rotation of the N-phosphinoyl group in PoxIm moieties eventually leads to the revival of frustrated carbene-borane pairs that can cleave H 2 . We believe that this work illustrates an essential role of dynamic conformational isomerization in the regulation of the reactivity of external-stimuli-responsive Lewis acid-base adducts that contain multifunctional substituents., (© 2021. The Author(s).)

Mechanochemistry enables unique reaction pathways in comparison to conventional thermal reactions. Notably, it can achieve selective hydrolysis of cellulose and chitin, a set of abundant and recalcitrant biomass, by solvent-free ball-milling in the presence of acid catalysts. Although the merits of mechanochemistry for this reaction are known, the reaction mechanism is still unclear. Here, we show how the mechanical forces produced by ball-milling activate the glycosidic bonds of carbohydrate molecules towards hydrolysis. This work uses experimental and theoretical evaluations to clarify the mechanism. The experimental results reveal that the ball-mill accelerates the hydrolysis by mechanical forces rather than local heat. Meanwhile, the classical and quantum mechanics calculations indicate the subnano to nano Newton order of tensile and compressive forces that activate polysaccharide molecules in the ball-milling process. Although previous studies have taken into account only the stretching of the molecules, our results show that compressive forces are stronger and effective for the activation of glycosidic bonds. Accordingly, in addition to stretching, compression is crucial for the mechanocatalytic reaction. Our work connects the classical physics of ball-milling on a macro scale with molecular activation at a quantum level, which would help to understand and control mechanochemical reactions.

Currently, the only approved treatments for gastrointestinal stromal tumor (GIST) are tyrosine kinase inhibitors (TKI), which eventually lead to the development of secondary resistance mutations in KIT or PDGFRA and disease progression. Herein, we identified G protein-coupled receptor 20 (GPR20) as a novel non-tyrosine kinase target in GIST, developed new GPR20 IHC, and assessed GPR20 expression in cell lines, patient-derived xenografts, and clinical samples from two institutes (United States and Japan). We studied GPR20 expression stratified by treatment line, KIT expression, GIST molecular subtype, and primary tumor location. We produced DS-6157a, an anti-GPR20 antibody-drug conjugate with a novel tetrapeptide-based linker and DNA topoisomerase I inhibitor exatecan derivative (DXd). DS-6157a exhibited GPR20 expression-dependent antitumor activity in GIST xenograft models including a GIST model resistant to imatinib, sunitinib, and regorafenib. Preclinical pharmacokinetics and safety profile of DS-6157a support its clinical development as a potential novel GIST therapy in patients who are refractory or have resistance or intolerance to approved TKIs. SIGNIFICANCE: GPR20 is selectively expressed in GIST across all treatment lines, regardless of KIT / PDGFRA genotypes. We generated DS-6157a, a DXd-based antibody-drug conjugate that exhibited antitumor activity in GIST models by a different mode of action than currently approved TKIs, showing favorable pharmacokinetics and safety profiles. This article is highlighted in the In This Issue feature, p. 1307 ., (©2021 American Association for Cancer Research.)

Recently, mechanical ball milling was applied to chitin depolymerization. The mechanical activation afforded higher selectivity toward glycosidic bond cleavage over amide bond breakage. Hence, the bioactive N -acetylglucosamine (GlcNAc) monomer was preferentially produced over glucosamine. In this regard, the force-dependent mechanochemical activation-deactivation process in the relaxed and pulled GlcNAc dimer undergoing deacetylation and depolymerization reactions was studied. For the relaxed case, the activation energies of the rate-determining steps (RDS) proved that the two reactions could occur simultaneously. Mechanical forces associated with ball milling were approximated with linear pulling and were introduced explicitly in the RDS of both reactions through force-modified potential energy surface (FMPES) formalism. In general, as the applied pulling force increases, the activation energy of the RDS of deacetylation shows no meaningful change, while that of depolymerization decreases. This result is consistent with the selectivity exhibited in the experiment. Energy and structural analyses for the depolymerization showed that the activation can be attributed to a significant change in the glycosidic dihedral at the reactant state. A lone pair of the neighboring pyranose ring O adopts a syn -periplanar conformation relative to the glycosidic bond. This promotes electron donation to the σ*-orbital of the glycosidic bond, leading to activation. Consequently, the Brønsted-Lowry basicity of the glycosidic oxygen also increases, which can facilitate acid catalysis.

Helicenes are promising candidates for chiral optoelectronic materials because of their helically twisted π-conjugated system. However, the emission intensity of unsubstituted helicenes is very weak (Φ f < 0.05) due to a small oscillator strength for the S 1 → S 0 transition. In this work, we investigated the substitution position of the [7]helicene framework so that the S 1 → S 0 transition has a large transition magnetic dipole moment (TMDM) and is partially symmetry-allowed. A [7]helicene derivative thus designed showed a large fluorescence emission rate ( k f = 0.02 ns -1 ) and a large TMDM for the S 1 → S 0 transition (| m | = 2.37 × 10 -20 erg·Gauss -1 ), which are more than 10 times greater than those of unsubstituted [7]helicene ( k f = 0.001 ns -1 , | m | = 0.045 × 10 -20 erg·Gauss -1 ). As a result, we achieved the [7]helicene derivative whose dissymmetry factor of CPL and fluorescence quantum yield were both high (| g CPL | = 1.3 × 10 -2 , Φ f = 0.17) in the solution phase.

Malondialdehyde-modified low-density lipoprotein (MDA-LDL) is recognized as a surrogate marker of lipid oxidation and is associated with arteriosclerosis. However, there are limited reports on the relationship between heart failure and MDA-LDL. Therefore, we aimed to determine whether MDA-LDL is activated in patients with left ventricular (LV) dysfunction and examine our hypothesis that the B-type natriuretic peptide (BNP) masks the enhancement of MDA-LDL in patients with LV dysfunction by its strong antioxidative action. The study population comprised 2,976 patients with various cardiovascular diseases. Patients were divided into four groups depending on the LV ejection fraction (LVEF) or plasma BNP level. A nonparametric analysis with the Kruskal-Wallis test was used to perform an interquartile comparison. In addition, structural equation modeling and Bayesian estimation were used to compare the effects of LVEF and BNP on MDA-LDL. MDA-LDL levels did not significantly change (P > 0.05) with respect to the degree of LVEF among the four groups. In contrast, MDA-LDL levels were significantly decreased (P < 0.001) with respect to the degree of BNP among the four groups. A path model based on structural equation modeling clearly showed a significant effect of LVEF (standardized regression coefficient; β: -0.107, P < 0.001) and BNP (β: -0.114, P < 0.001) on MDA-LDL, with a significant inverse association between LVEF and BNP (correlation coefficient -0.436, P < 0.001). MDA-LDL should be activated in patients with LV dysfunction; however, BNP is thought to exert a strong compensatory suppression on lipid oxidation, masking the relationship between heart failure and lipid oxidation., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

A 77-year-old man was diagnosed with obstructive sigmoid colon cancer invading the psoas major and iliac muscles. To avoid the postoperative paralysis of the lower limb, a self-expandable metallic stent(SEMS)was placed, and systemic chemotherapy was administered subsequently. After 4 courses of SOX, Hartmann's procedure was performed. The patient did not develop lower limb paralysis and is alive without recurrence 2 years and 3 months postoperatively. This case suggests that preoperative metallic SEMS placement and neoadjuvant chemotherapy could be an effective treatment for locally advanced colon cancer with obstruction and invasion of the adjacent tissues.

Spin-inversion dynamics in O 2 binding to a model heme complex, which consisted of Fe(II)-porphyrin and imidazole, were studied using nonadiabatic wave packet dynamics calculations. We considered three active nuclear degrees of freedom in the dynamics, including the motions along the Fe-O distance, Fe-O-O angle, and Fe out-of-plane distance. Spin-free potential energy surfaces for the singlet, triplet, quintet, and septet states were developed using density functional theory calculations, and spin-orbit coupling elements were obtained from CASSCF-level electronic structure calculations. The spin-inversion mainly occurred between the singlet state and one of the triplet states due to large spin-orbit couplings and the contributions of other states were extremely small. The present quantum dynamics calculations suggested that the narrow crossing region model plays a dominant role in the O 2 binding dynamics. In addition, the one-dimensional Landau-Zener model underestimated the nonadiabatic transition probability., (© 2020 Wiley Periodicals LLC.)

Some monoclonal antibodies undergo liquid-liquid phase separation owing to self-attractive associations involving electrostatic and other soft interactions, thereby rendering monoclonal antibodies unsuitable as therapeutics. To mitigate the phase separation, formulation optimization is often performed. However, this is sometimes unsuccessful because of the limited time for the development of therapeutic antibodies. Thus, protein mutations with appropriate design are required. In this report, we describe a case study involving the design of mutants of negatively charged surface residues to reduce liquid-liquid phase separation propensity. Physicochemical analysis of the resulting mutants demonstrated the mutual correlation between the sign of second virial coefficient B2, the Fab dipole moment, and the reduction of liquid-liquid phase separation propensity. Moreover, both the magnitude and direction of the dipole moment appeared to be essential for liquid-liquid phase separation propensity, where electrostatic interaction was the dominant mechanism. These findings could contribute to a better design of mutants with reduced liquid-liquid phase separation propensity and improved drug-like biophysical properties., Competing Interests: While all the authors were employed in Daiichi Sankyo Co., Ltd. when this work was performed, Dr. Jun Hasegawa has since moved, and his current affiliation is with Osaka University, Japan. However, this does not alter our adherence to all the PLOS ONE policies on sharing data and materials, as detailed online in the guide for authors.

There is a great interest in direct conversion of methane to valuable chemicals. Recently, we reported that silica-supported liquid-metal indium catalysts (In/SiO 2 ) were effective for direct dehydrogenative conversion of methane to higher hydrocarbons. However, the catalytic mechanism of liquid-metal indium has not been clear. Here, we show the catalytic mechanism of the In/SiO 2 catalyst in terms of both experiments and calculations in detail. Kinetic studies clearly show that liquid-metal indium activates a C-H bond of methane and converts methane to ethane. The apparent activation energy of the In/SiO 2 catalyst is 170 kJ mol -1 , which is much lower than that of SiO 2 , 365 kJ mol -1 . Temperature-programmed reactions in CH 4 , C 2 H 6 , and C 2 H 4 and reactivity of C 2 H 6 for the In/SiO 2 catalyst indicate that indium selectively activates methane among hydrocarbons. In addition, density functional theory calculations and first-principles molecular dynamics calculations were performed to evaluate activation free energy for methane activation, its reverse reaction, CH 3 -CH 3 coupling via Langmuir-Hinshelwood (LH) and Eley-Rideal mechanisms, and other side reactions. A qualitative level of interpretation is as follows. CH 3 -In and H-In species form after the activation of methane. The CH 3 -In species wander on liquid-metal indium surfaces and couple each other with ethane via the LH mechanism. The solubility of H species into the bulk phase of In is important to enhance the coupling of CH 3 -In species to C 2 H 6 by decreasing the formation of CH 4 though the coupling of CH 3 -In species and H-In species. Results of isotope experiments by combinations of CD 4 , CH 4 , D 2 , and H 2 corresponded to the LH mechanism., Competing Interests: The authors declare no competing financial interest., (© 2020 American Chemical Society.)

There are diverse reactions including spin-state crossing, especially the reactions catalyzed by transition metal compounds. To figure out the mechanisms of such reactions, the discussion of minimum energy intersystem crossing (MEISC) points cannot be avoided. These points may be the bottleneck of the reaction or inversely accelerate the reactions by providing a better pathway. It is of great importance to reveal their role in the reactions by computationally locating the position of the MEISC points together with the reaction pathway. However, providing a proper initial guess for the structure of the MEISC point is not as easy as that of the transition state. In this work, we extended the nudged elastic band (NEB) method for multiple spin systems, which is named the multiple spin-state NEB method, and it is successfully applied to find the MEISC points while optimizing the reaction pathway. For more precisely locating the MEISC point, a revised approach was adopted. Meanwhile, our examples also suggest that special attention should be paid to the criterion to define an image optimized as the MEISC point.

Self-assembled multilayer iron(0) nanoparticles (NPs, 6-10 nm), namely, sulfur-modified Au-supported Fe(0) [SAFe(0)], were developed for ligand-free one-pot carbon-carbon/carbon-nitrogen bond-forming reactions. SAFe(0) was successfully prepared using a well-established metal-nanoparticle catalyst preparative protocol by simultaneous in situ metal NP and nanospace organization (PSSO) with 1,4-bis(trimethylsilyl)-1,4-dihydropyrazine ( Si -DHP) as a strong reducing agent. SAFe(0) was easy to handle in air and could be recycled with a low iron-leaching rate in reaction cycles.

The development of simple catalysts with high performance in the selective oxidation of methane to syngas at low temperature has attracted much attention. Here we report a nickel-based solid catalyst for the oxidation of methane, synthesised by a facile impregnation method. Highly dispersed ultra-small NiO particles of 1.6 nm in size are successfully formed on the MOR-type zeolite. The zeolite-supported nickel catalyst gives continuously 97-98% methane conversion, 91-92% of CO yield with a H 2 /CO ratio of 2.0, and high durability without serious carbon deposition onto the catalyst at 973 K. DFT calculations demonstrate the effect of NiO particle size on the C-H dissociation process of CH 4 . A decrease in the NiO particle size enhances the production of oxygen originating from the NiO nanoparticles, which contributes to the oxidation of methane under a reductive environment, effectively producing syngas., (© 2020. The Author(s).)

Purpose: Neovascular age-related macular degeneration (nAMD) results from choroidal neovascularization (CNV) and causes severe vision loss. Intravitreal anti-vascular endothelial growth factor (VEGF) therapies have significantly improved therapeutic outcomes; however, a substantial number of patients experience disease progression. Roundabout 4 (ROBO4) has been reported to be a vascular-specific protein that stabilizes vasculature in ocular pathological angiogenesis. To explore ROBO4 targeting as a novel treatment against neovascularization, we generated a humanized anti-human ROBO4 antibody, DS-7080a, and evaluated its efficacy., Methods: ROBO4 mRNA in human whole eye cross-sections was examined by in situ hybridization. Human umbilical vein endothelial cell (HUVEC) migration was measured in the presence of VEGF, basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), or conditioned medium of primary human retinal pigment epithelial (HRPE) cells. CNV was induced in cynomolgus monkeys by laser irradiation. Vascular leakage was measured by fluorescein angiography, and pathological changes were determined by histology., Results: ROBO4 mRNA was detected in choroidal vessels of nAMD patients. DS-7080a suppressed HGF- or bFGF-induced HUVEC migration in addition to that induced by VEGF. Further, HUVEC migration induced by HRPE-conditioned medium was inhibited by either DS-7080a or ranibizumab in a similar manner, and the combination of these showed further inhibition. In a laser-induced CNV monkey model, single intravitreous administration of 1.1 mg/eye of DS-7080a reduced the incidence of grade 4 leakage from 44.45% in control eyes to 1.85% ( P < 0.05 by Dunnett's test)., Conclusions: Anti-ROBO4 antibody DS-7080a suppressed HUVEC migration in a distinctly different fashion from anti-VEGF agents and improved laser-induced CNV in non-human primates., Translational Relevance: DS-7080a may be a novel treatment option for nAMD., Competing Interests: Disclosure: Y. Isumi, Daiichi Sankyo Co., Ltd. (F); S. Hayashi, Daiichi Sankyo Co., Ltd. (F); T. Inoue, Daiichi Sankyo Co., Ltd. (F); Y. Yoshigae, Daiichi Sankyo Co., Ltd. (F); T. Sato, Daiichi Sankyo Co., Ltd. (F); J. Hasegawa, Daiichi Sankyo Co., Ltd. (F); T. Agatsuma, Daiichi Sankyo Co., Ltd. (F), (Copyright 2020 The Authors.)

The ring-opening process was generally considered as the rate-determining step for aromatic volatile organic compound photocatalytic degradation. A sophisticated and intensive degradation pathway is critical to the poor removal efficiency and low mineralization. In the present contribution, we successfully tailored and identified the ring-opening pathway of toluene elimination by electron delocalization in a borocarbonitride photocatalyst. By means of modulation of the dopant coordination configuration and electron geometry in the catalyst, the lone electrons of carbon transform into delocalized counterparts, sequentially elevating the interaction between the toluene molecules and photocatalyst. The aromatic ring of toluene can be attacked directly in the effect of electron delocalization without engendering additional intermediate species, significantly facilitating the removal and mineralization of toluene. This unprecedented route-control strategy alters the aromatic-ring-based reaction behavior from toluene to CO 2 and paves a way to purify the refractory pollutants from the top design.

Carbon dioxide (CO2) was used as a C1 source to prepare silyl formates, formamides, and aldehydes. Tetrabutylammonium acetate (TBAA) catalyzed the solvent-free N-formylation of amines with CO2 and hydrosilane to give formamides including Weinreb formamide, Me(MeO)NCHO, which was successively converted into aldehydes by one-pot reactions with Grignard reagents.

Bifunctional Al III porphyrins with quaternary ammonium halides, 2-Cl and 2-Br , worked as excellent catalysts for the copolymerization of cyclohexene oxide (CHO) and CO 2 at 120 °C. Turnover frequency (TOF) and turnover number (TON) reached 10 000 h -1 and 55 000, respectively, and poly(cyclohexene carbonate) (PCHC) with molecular weight of up to 281 000 was obtained with a catalyst loading of 0.001 mol%. In contrast, bifunctional Mg II and Zn II counterparts, 3-Cl and 4-Cl , as well as a binary catalyst system, 1-Cl with bis(triphenylphosphine)iminium chloride (PPNCl), showed poor catalytic performances. Kinetic studies revealed that the reaction rate was first-order in [CHO] and [ 2-Br ] and zero-order in [CO 2 ], and the activation parameters were determined: Δ H ‡ = 12.4 kcal mol -1 , Δ S ‡ = -26.1 cal mol -1 K -1 , and Δ G ‡ = 21.6 kcal mol -1 at 80 °C. Comparative DFT calculations on two model catalysts, Al III complex 2' and Mg II complex 3' , allowed us to extract key factors in the catalytic behavior of the bifunctional Al III catalyst. The high polymerization activity and carbonate-linkage selectivity originate from the cooperative actions of the metal center and the quaternary ammonium cation, both of which facilitate the epoxide-ring opening by the carbonate anion to form the carbonate linkage in the key transition state such as TS3b (Δ H ‡ = 13.3 kcal mol -1 , Δ S ‡ = -3.1 cal mol -1 K -1 , and Δ G ‡ = 14.4 kcal mol -1 at 80 °C)., (This journal is © The Royal Society of Chemistry 2020.)

Spin-inversion mechanisms in O 2 binding to a model heme complex, consisting of Fe(II)-porphyrin and imidazole, were investigated using density-functional theory calculations. First, we applied the recently proposed mixed-spin Hamiltonian method to locate spin-inversion structures between different total spin multiplicities. Nine spin-inversion structures were successfully optimized for the singlet-triplet, singlet-quintet, triplet-quintet, and quintet-septet spin-inversion processes. We found that the singlet-triplet spin-inversion points are located around the potential energy surface region at short Fe-O distances, whereas the singlet-quintet and quintet-septet spin-inversion points are located at longer Fe-O distances. This suggests that both narrow and broad crossing models play roles in O 2 binding to the Fe-porphyrin complex. To further understand spin-inversion mechanisms, we performed on-the-fly Born-Oppenheimer molecular dynamics calculations. The reaction coordinates, which are correlated to the spin-inversion dynamics between different spin multiplicities, are also discussed., (© 2020 Wiley Periodicals, Inc.)

Roles of internal salicylate donors (SID) in enhancing activity and stereoselectivity of Ziegler-Natta catalyzed propylene (PP) polymerization were examined using DFT calculations. Five salicylate donors were studied. The chelate mode is the preferred adsorption mode. The linear relationship (R 2 = 0.96) between calculated adsorption energies (E ads ) of five SIDs and the experimental PP activities was observed. Thus, the SID with the strongest adsorption energy will provide the highest activity in agreement with our previous studies. Compared with diisobutyl phthalate (DIBP), which is the industrial electron donor, SID has stronger E ads . The insertion step, which involves the π-complex formation (∆E π and the insertion activation or intrinsic activation energy (E a ) for PP polymerization was also examined. The relation between ln(activity) and apparent activation energy (E a (app)), which is ∆E π + E a for the primary(1,2)- re insertion with R 2 = 0.99, was observed. The salicylate donor also has a lower E a (app) than that of DIBP. This explains the better catalytic performance of SID. Our results also demonstrated that the size and the type of hydrocarbon substituents play a key role in controlling stereoselectivity and activity. In addition, we found a good relationship between E ads and both intrinsic (E a ) and apparent (E a (app)) activation energies of five salicylate donors with R 2 of 0.90 and 0.97, respectively., Competing Interests: The authors declare no conflict of interest.

A binder plays an important role in stabilizing the electrode structure and improving the cyclic stability of batteries. However, the traditional binders are no longer satisfactory in lithium-sulfur (Li-S) batteries because of their failure in accommodating the large volume changes of sulfur and trapping soluble intermediate polysulfides, thus causing severe capacity decay. In this work, we prepared a multifunctional binder for Li-S batteries by merely modifying the acacia gum (AG), a low-cost biomass polymer, with l-cysteine under mild conditions. Owing to the introduced amino and carboxyl branches by the l-cysteine, the modified AG shows enhanced polysulfide trapping ability and can effectively restrain the shuttling of polysulfides. In addition, the introduction of branches can help form a cross-linked 3D network with better mechanical strength and flexibility for adhering sulfur and accommodating the volume changes of cathode materials. As a result, compared with the normally used polyvinylidene fluoride binder and the unmodified AG binder, the l-cysteine-modified AG binder effectively enhanced the rate capability and cycling stability of the Li-S batteries directly using sulfur as the cathode, showing a promising way to prompt the practical use of Li-S batteries.

Methyl-selective α-oxygenation of tertiary amines is a highly attractive approach for synthesizing formamides while preserving the amine substrate skeletons. Therefore, the development of efficient catalysts that can advance regioselective α-oxygenation at the N-methyl positions using molecular oxygen (O 2 ) as the terminal oxidant is an important subject. In this study, we successfully developed a highly regioselective and efficient aerobic methyl-selective α-oxygenation of tertiary amines by employing a Cu/nitroxyl radical catalyst system. The use of moderately hindered nitroxyl radicals, such as 1,5-dimethyl-9-azanoradamantane N-oxyl (DMN-AZADO) and 1-methyl-2-azaadamanane N-oxyl (1-Me-AZADO), was very important to promote the oxygenation effectively mainly because these N-oxyls have longer life-times than less hindered N-oxyls. Various types of tertiary N-methylamines were selectively converted to the corresponding formamides. A plausible reaction mechanism is also discussed on the basis of experimental evidence, together with DFT calculations. The high regioselectivity of this catalyst system stems from steric restriction of the amine-N-oxyl interactions., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Reactions based on transition-metal-catalyzed C-O bond cleavage have attracted much attention as a new synthetic method. Until now, several intermolecular reactions via C-O bond cleavage of aryl ethers, alkenyl ethers, esters, and others have been reported. Here we report an unprecedented C-O bond cleavage of 3-phenoxy acrylic acid derivatives, followed by intramolecular C-O bond formation with alkynes. This reaction gave 2,3-disubstituted benzofurans having useful functional groups-silyl substituents and acrylic acid derivatives-at the 2- and 3-positions, respectively. This report also described theoretical (DFT) insights into the mechanism.

The mechanism of C-H activation of methane by liquid indium, which is the first step of the dehydrogenative conversion of methane to higher hydrocarbons, was investigated using density functional theory calculations. In the first-principle molecular dynamics trajectory at the experimental temperature (1200 K), low-coordinated indium atoms continuously appear on the disordered liquid surface. The C-H cleavage is endothermic on clean surfaces, while the low-coordinated indium atoms reduce the endothermicity significantly. In small indium clusters, which are models of low-coordinated atoms on a surface, the calculated activation energy is much smaller than that on the clean surface. The energy level of the methane C-H σ* orbital is reduced by the interaction with the indium 5pσ orbitals. In 2 shows the lowest activation energy and exothermicity in the C-H bond cleavage.

Selective catalytic reduction with NH 3 (NH 3 -SCR) is the most efficient technology to reduce the emission of nitrogen oxides (NO x ) from coal-fired industries, diesel engines, etc. Although V 2 O 5 -WO 3 (MoO 3 )/TiO 2 and CHA structured zeolite catalysts have been utilized in commercial applications, the increasing requirements for broad working temperature window, strong SO 2 /alkali/heavy metal-resistance, and high hydrothermal stability have stimulated the development of new-type NH 3 -SCR catalysts. This review summarizes the latest SCR reaction mechanisms and emerging poison-resistant mechanisms in the beginning and subsequently gives a comprehensive overview of newly developed SCR catalysts, including metal oxide catalysts ranging from VO x , MnO x , CeO 2 , and Fe 2 O 3 to CuO based catalysts; acidic compound catalysts containing vanadate, phosphate and sulfate catalysts; ion exchanged zeolite catalysts such as Fe, Cu, Mn, etc. exchanged zeolite catalysts; monolith catalysts including extruded, washcoated, and metal-mesh/foam-based monolith catalysts. The challenges and opportunities for each type of catalysts are proposed while the effective strategies are summarized for enhancing the acidity/redox circle and poison-resistance through modification, creating novel nanostructures, exposing specific crystalline planes, constructing protective/sacrificial sites, etc. Some suggestions are given about future research directions that efforts should be made in. Hopefully, this review can bridge the gap between newly developed catalysts and practical requirements to realize their commercial applications in the near future.