The Role of Frustrated Lewis Pair in Catalytic Transfer Hydrogenation of Furfural using Nickel Single-Atom Catalysts: A Theoretical Study.

The burgeoning field of frustrated Lewis pair (FLP) heterogeneous catalysts has garnered significant interest in recent years, primarily due to their inherent ability to activate H-source molecules, thereby facilitating hydrogenation reactions. In this study, non-precious transition metal atoms were anchored onto several models of pyridinic nitrogen incorporated graphene sheet. Theoretical calculations substantiated energy barriers as low as 0.

Anchoring Pt Single-Atom Sites on Vacancies of MgO(Al) Nanosheets as Bifunctional Catalysts to Accelerate Hydrogenation-Cyclization Cascade Reactions.

The direct hydrogenation of 2-nitroacylbenzene to 2,1-benzisoxazole presents a significant challenge in the pharmaceutical and fine chemicals industries. In this study, a defect engineering strategy is employed to create bifunctional single-atom catalysts (SACs) by anchoring Pt single atoms onto metal vacancies within MgO(Al) nanosheets. The resultant Pt/MgO(Al) SAC displays an exceptional catalytic activity and selectivity in the hydrogenation-cyclization of 2-nitroacylbenzene, achieving a 97.

Selective Increase in CO Electroreduction to Ethanol Activity at Nanograin-Boundary-Rich Mixed Cu(I)/Cu(0) Sites via Enriching Co-Adsorbed CO and Hydroxyl Species.

Selective producing ethanol from CO electroreduction is highly demanded, yet the competing ethylene generation route is commonly more thermodynamically preferred. Herein, we reported an efficient CO-to-ethanol conversion (53.5 % faradaic efficiency at -0.

[Two new sesquiterpenes in Qi-nan Aquilariae Lignum Resinatum].

This study aimed to investigate the chemical constituents of supercritical extract from Qi-nan Aquilariae Lignum Resinatum by silica gel column chromatography, thin-layer chromatography, and semi-preparative high-performance liquid chromatography. One new elemane-type and one new eudesmane-type sesquiterpene compounds were isolated from the extract, and their structures were identified by MS, UV, IR, NMR, and ECD spectroscopic techniques, and named aquqinanol C(1) and aquqinanol D(2). Both compounds are novel compounds.

One-pot solvothermal synthesis of In-doped amino-functionalized UiO-66 Zr-MOFs with enhanced ligand-to-metal charge transfer for efficient visible-light-driven CO reduction.

Metal organic frameworks (MOFs) with high porosity and highly tunable physical/chemical properties can serve as heterogeneous catalysts for CO photoreduction, but the application is hindered by the large band gap (E) and insufficient ligand-to-metal charge transfer (LMCT). In this study, a simple one-pot solvothermal strategy is proposed to prepare an amino-functionalized MOF (aU(Zr/In)) featuring an amino-functionalizing ligand linker and In-doped Zr-oxo clusters, which enables efficient CO reduction driven with visible light. The amino functionalization leads to a significant reduction of E as well as a charge redistribution of the framework, allowing the absorption of visible light and the efficient separation of photogenerated carriers.

Ligand Conformation Fixation Strategy for Expanding the Structural Diversity of Copper-Tricarboxylate Frameworks and CH Purification Performance Studies.

Structural and functional expansion of metal-organic frameworks (MOFs) is fundamentally important because it not only enriches the structural chemistry of MOFs but also facilitates the full exploration of their application potentials. In this work, by employing a dual-site functionalization strategy to lock the ligand conformation, we designed and synthesized a pair of biphenyl tricarboxylate ligands bearing dimethyl and dimethoxy groups and fabricated their corresponding framework compounds through coordination with copper(II) ions. Compared to the monofunctionalized version, introduction of two side groups can significantly fix the ligand conformation, and as a result, the dual-methoxy compound exhibited a different network structure from the mono-methoxy counterpart.

Substituent Engineering-Enabled Structural Rigidification and Performance Improvement for C/CO Separation in Three Isoreticular Coordination Frameworks.

Construction of porous solid materials applied to the adsorptive removal of CO from C hydrocarbons is highly demanded thanks to the important role C hydrocarbons play in the chemical industry but quite challenging owing to the similar physical parameters between C hydrocarbons and CO. In particular, the development of synthetic strategies to simultaneously enhance the uptake capacity and adsorption selectivity is very difficult due to the trade-off effect frequently existing between both of them. In this work, a combination of the dicopper paddlewheel unit and 4-pyridylisophthalate derivatives bearing different substituents afforded an isoreticular family of coordination framework compounds as a platform.

One-pot solvothermal synthesis of flower-like Fe-doped InS/FeS S-scheme hetero-microspheres with enhanced interfacial electric field and boosted visible-light-driven CO reduction.

S-scheme heterojunctions hold great potential for CO photoreduction into solar fuels, but their activities are severely limited by the low efficiency of interfacial charge transfer. In this work, a facile one-pot solvothermal reaction has been developed to dope Fe into flower-like InS/FeS hetero-microspheres (Fe-InS/FeS HMSs), which are demonstrated as an efficient S-scheme photocatalyst for visible-light-driven CO photoreduction. The doping of Fe not only reduces the bandgap of InS and thus extends the optical response to the visible-light region, but also increases the densities of donors and sulfur vacancies, which leads to an elevated Fermi level (E).

Theoretical understanding on all-solid frustrated Lewis pair sites of CN anchored by single metal atom.

The design of all-solid heterogeneous catalysts with frustrated Lewis pairs (FLPs) has attracted much attention recently because of their appealing low dissociation energy for H molecules due to which a promotion of hydrogenation reaction is expected. The sterically encumbered Lewis acid (metal site) and base (nitrogen site) in the cavity of single transition metal atom-doped M/CN sheets make them potential candidates for the design of catalysts with FLPs, while a comprehensive understanding of their intrinsic property and reactivity is still lacking. Calculations show that the complete dissociation of the H molecule into two H* states at the N sites requires two steps: heterolytic cleavage of the H molecule and the transfer of H* from the metal site to the N site, which are strongly related to the acidity of the metal site.

Cadinane-type sesquiterpenoid dimeric diastereomers hibisceusones A-C from infected stems of Hibiscus tiliaceus with cytotoxic activity against triple-negative breast cancer cells.

Three new cadinane-type sesquiterpenoid dimeric diastereomers (1-3) named hibisceusones A-C were obtained from the infected stems of Hibiscus tiliaceus. The structures were determined by NMR spectroscopy and MS techniques, and the absolute configurations were assigned by ECD and single-crystal X-ray diffraction techniques. Compounds 1-3 are diastereomers, and contain a 1,4-dioxane ring linearly fused to different cadinane-type polycyclic skeletons.

Steering Catalytic Activity and Selectivity of CO Photoreduction to Syngas with Hydroxy-Rich Cu S@R -NiCo O Double-Shelled Nanoboxes.

Simultaneous transformation of CO and H O into syngas (CO and H ) using solar power is desirable for industrial applications. Herein, an efficient photocatalyst based on double-shelled nanoboxes, with an outer shell of hydroxy-rich nickel cobaltite nanosheets and an inner shell of Cu S (Cu S@R -NiCo O ), is prepared via a multistep templating strategy. The high performance of Cu S@R -NiCo O (7.

Mechanism of Catalytic Transfer Hydrogenation for Furfural Using Single Ni Atom Catalysts Anchored to Nitrogen-Doped Graphene Sheets.

Catalytic transfer hydrogenation (CTH) of α,β-unsaturated aldehydes using single metal atom catalysts supported on nitrogen-incorporated graphene sheet (M-N-Gr) materials has attracted increasing attention recently, yet the reaction mechanism remains to be explored. Compared to the Ni-N-Gr model in which the dissociation of isopropanol is highly unfavorable as a result of steric hindrance and inertness of the Ni-N site embedded in graphene, the Ni-N site in Ni-N-Gr is more active and facilitates the formation of *H with isopropanol as the H donor, where the dissociation of H from isopropanol with an energy barrier of 0.83 eV is the rate-determining step.

Callnudoids A-H: Highly modified labdane diterpenoids with anti-inflammation from the leaves of Callicarpa nudiflora.

Eight undescribed 3,4-seco-norlabdane diterpenoids, callnudoids A-H, as well as two known analogues were isolated from the leaves of Callicarpa nudiflora. The structures were elucidated using spectroscopic methods and were compared with published NMR spectroscopic data. The absolute configurations of callnudoids D and E were defined based on ECD data or single-crystal X-ray diffraction.

Perspective on Defective Semiconductor Heterojunctions for CO Photoreduction.

Photocatalytic CO reduction to value-added chemicals is a green solution to concurrently address CO emission and energy issues, and semiconductor heterojunctions hold great potential to achieve such conversion. However, the photocatalytic performance of the existing heterojunctions is limited by the low interfacial charge transfer efficiency and sluggish surface reaction kinetics. To overcome these obstacles, defect engineering has been applied to heterojunctions to boost CO photoreduction in the past 5 years.

ZnSe Nanorods-CsSnCl Perovskite Heterojunction Composite for Photocatalytic CO Reduction.

Utilizing sunlight to convert CO into chemical fuels could simultaneously address the greenhouse effect and fossil fuel crisis. ZnSe nanocrystals are promising candidates for photocatalysis because of their low toxicity and excellent photoelectric properties. However, pristine ZnSe generally has low catalytic activities due to serious charge recombination and the lack of efficient catalytic sites for CO reduction.

Cadinane-Type Sesquiterpenoids with Cytotoxic Activity from the Infected Stems of the Semi-mangrove .

Eight new cadinane sesquiterpenoids (-), along with two known compounds ( and ), were isolated from infected stems of the semi-mangrove plant, . The structures of compounds - were elucidated through the analysis of their 1D and 2D NMR and MS data, and their absolute configurations were determined by comparing their experimental and calculated ECD spectra and by single-crystal X-ray diffraction. The two confused known compounds ( and ) were resolved using single-crystal X-ray crystallography.

Single non-noble metal atom doped CN catalysts for chemoselective hydrogenation of 3-nitrostyrene.

Improving the reaction selectivity and activity for challenging substrates such as nitroaromatics bearing two reducible functional groups is important in industry, yet remains a great challenge using traditional metal nanoparticle based catalysts. In this study, single metal atom doped M-CN catalysts were theoretically screened for selective hydrogenation of 3-nitrostyrene to 3-vinylaniline with H as the H-source. Among 20 M-CN catalysts, the non-noble Mn-CN catalyst was found to have excellent reaction selectivity.

Improving Ethane/Ethylene Separation Performance of Isoreticular Metal-Organic Frameworks Substituent Engineering.

The preferential capture of ethane (CH) over ethylene (CH) presents a very cost-effective and energy-saving means applied to adsorptive separation and purification of CH with a high product purity, which is however challenged by low selectivity originating from their similar molecular sizes and physical properties. Substituent engineering has been widely employed for selectivity regulation and improvement, but its effect on CH/CH separation has been rarely explored to date. In this work, four isoreticular coordination framework compounds based on 5-(pyridin-3-yl)isophthalate ligands bearing different substituents were rationally constructed.

Hepatic perivascular epithelioid cell tumor: Clinicopathological analysis of 26 cases with emphasis on disease management and prognosis.

Background: Perivascular epithelioid cell tumor (PEComa) is an uncommon tumor of mesenchymal origin. Cases of PEComa in the liver are extremely rare.

Aim: To analyze the clinicopathological features and treatment of hepatic PEComa and to evaluate the prognosis after different treatments.

Structural Revisions of Two Highly Aromatic Naphthoquinone-Derived Dimers Based on NMR Analysis, Computer-Assisted Structure Elucidation Methods, and Computations.

Eleucanainones A and B are two structurally complex naphthoquinone-derived dimers whose structure identification is difficult. Large yellow fragments of the preliminary CASE (computer-assisted structure elucidation) analysis revealed that the original structures might be questionable. Structural revisions of the two compounds were proposed on the basis of NMR analysis, CASE methods, conformation analysis, and DFT (density functional theory) NMR calculations with a custom DP4+ analysis.

Atomically Dispersed Vanadium Sites Anchored on N-Doped Porous Carbon for the Efficient Oxidative Coupling of Amines to Imines.

Single-atom catalysts effectively integrate the respective advantages of homogeneous and heterogeneous catalysts and are a pioneering research frontier in catalysis by virtue of their maximized utility of metal atoms and distinct atomic configuration. However, development of such catalysts is still in the early stages. Herein, atomically dispersed vanadium (V) sites that are coordinated by N atoms and inlaid within N-incorporated porous carbon networks were prepared through a top-down strategy by annealing a V-containing metal-organic framework, NH-MIL-101(V), followed by acid etching.

[Study progress on chemical constituents and biological activities of Trigonostemon genus].

The plants of the Trigonostemon sp. genus(Euphorbiaceae family) comprising about 50 species worldwide are mainly distributed in tropical and subtropical Asia, 10 species of which can be found in southern of China. Phytochemical studies on the plants in the genus have demonstrated a large amount of terpenoids and alkaloids.

An -oxide-functionalized nanocage-based copper-tricarboxylate framework for the selective capture of CH.

The selective capture of C2H2 from C2H2-C2H4 and C2H2-CO2-CH4 mixtures is a very essential but highly challenging process during C2H4 and C2H2 purification in the chemical industry. In this work, by virtue of using oxygen-atom-rich C2H2 recognition sites, we, for the first time, designed and synthesized an N-oxide-functionalized tricarboxylate ligand and utilized it to successfully construct a copper-based MOF. N-Oxide functionalization exerted a significant effect on the ligand conformation, thus resulting in a new topological network that is different from that of the unoxidized parent compound.

Natural Nitrogenous Sesquiterpenoids and Their Bioactivity: A Review.

Nitrogenous sesquiterpenoids fromnatural sourcesare rare, so unsurprisingly neither the potentially valuable bioactivity nor thebroad structural diversity of nitrogenous sesquiterpenoids has been reviewed before. This report covers the progressduring the decade from 2010 to February 2020 on the isolation, identification, and bioactivity of 391 nitrogen-containing natural sesquiterpenes from terrestrial plant, marine organisms, and microorganisms. This complete and in-depth reviewshouldbe helpful for discovering and developing new drugs of medicinal valuerelated to natural nitrogenous sesquiterpenoids.

Preparation of CaF Microspheres with Nanopetals for Water Vapor Adsorption.

The hierarchically structured flower-like CaF microspheres with nanopetals, named FL-CaF, were synthesized via a hydrothermal method using calcium acetate Ca(Ac) and NaBF as calcium and fluorine sources, respectively, assisted by the chelating reagent trisodium citrate (NaCit) with the optimal pH of the synthesis solution. Meanwhile, a reference sample, named FL-CaF-R, was reproduced using ethylenediaminetetraacetic acid disodium salt (NaEDTA) as the chelating reagent, based on the recipe and synthesis procedure from the literature. Various techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform-infrared spectroscopy, and N adsorption-desorption at 77 K were then used to characterize the synthesized samples.