Computational and experimental evidence for Sb(v) metal mediated C-H activation and oxidative functionalization of arenes.

Inorganic Sb complexes are one of the most well-known Lewis acids that typically indirectly activate nonpolar hydrocarbon bonds by acting as Brønsted superacids. Here we have used a combination of quantum-chemical calculations and experiments to demonstrate that inorganic Sb complexes can directly activate aromatic sp C-H bonds and induce oxidative functionalization to form aryl esters. C-H activation was first demonstrated by reaction of Sb(TFA) (TFA = trifluoroacetate) with toluene at moderate temperatures that resulted in Sb-C bond intermediates (TFA)Sb(-tolyl) and (TFA)Sb(-tolyl).

Superhydrophilic Amidoxime-Modified Poly(vinyl alcohol) Fibers for Enhanced Uranium Extraction from Seawater.

The efficient extraction of uranium from seawater is an important step in the sustainable development of nuclear energy. Polymer-based absorbents are considered to be ideal materials due to their high adsorption properties and industrialization feasibility. Their adsorption performance could be further improved by enlarging the specific surface area and enhancing hydrophilicity.

A cation-mediated fluorescence enhanced hydrogel for the sensitive detection of uranyl ions in water.

Uranium, in terms of both its radioactivity and chemical toxicity, poses significant environmental and health risks when released through nuclear industry activities and its mining. The sensitive detection of uranyl ions (UO) in wastewater is crucial for mitigating these risks and safeguarding public health. Herein, we present an innovative approach by synthesizing the functional monomer 6-(3-(2-(methacryloyloxy)ethyl)ureido)picolinate (K6MUPA) to create a novel europium ion (Eu)-K6MUPA-AAm hydrogel sensor.

Constructing Biomimetic Nanochannels for High-Capacity Capture of Uranyl Tricarbonate Complex Ions.

Biomimetic nanochannels enable fast and selective transport of mononuclear metal ions; however, their construction for complex ion transport remains in its infancy due to the nonuniform charge distribution and large geometric dimensions of coordination compounds. Herein, an ionic electrostatic interaction template strategy is proposed to prepare biomimetic channels for the capture of complex ions. Using the [UO(CO)] ion as a template, various quaternary ammonium monomers with lengths of 6.

Monomer Design Enables Mechanistic Mapping of Anionic Ring-Opening Polymerization of Aromatic Thionolactones.

Degradable chalcogenide polyesters, e.g., polythioesters (PTEs), typically exhibit improved thermal, mechanical, and optical properties.

Theoretical Exploration of the Synergistic Effect of Phosphate and Amidoxime for Uranium Recovery from Seawater.

Highly selective extraction of uranium from seawater is currently extremely challenging. Although the amidoxime group (HAO) is the commonly used ligand in seawater uranium extraction, it also has strong binding capacity for vanadium ion. It has been shown that the introduction of phosphate groups into amidoxime-based adsorbents can improve the adsorption performance of materials through a synergistic effect between functional groups.

Precise Electrocatalysis on Fe-Porphyrin Conjugated Networks Achieves Energy-Efficient Extraction of Uranium.

Electrochemical extraction has the potential to enhance uranium (U) extraction capacity and rates, but thus far, high selectivity and energy efficiency have not been achieved through the design of electrode materials. Herein, a precise electrocatalysis strategy is developed using a Ferrum (Fe) porphyrin-phenanthroline conjugated network (Fe@PDACN) for energy-efficient uranium extraction. The phenanthroline provides specific binding sites for selective enrichment of U(VI) at active sites (K = 2.

Intermolecular Assembly of Dual Hydrogen Bonding Regio-Isomers Generates High-Performance AIE Probes.

Regio-isomers are utilized to design innovative AIE luminogens (AIEgens) by regulating molecular aggregation behavior. However, relevant examples are limited, and the underlying mechanism is not fully understood. Herein, a regio-isomer strategy is used to develop AIEgens by precisely regulating the intermolecular interactions in the solid state.

Study on the Thermal Decomposition Risk of 3,7-Dinitro-1,3,5,7-tetraazabicyclo[3,3,1]nonane under Different Conditions.

Given its role as a pivotal intermediate in octogen production, the thermal safety of DPT is of paramount importance due to its significant thermal hazard. To assess the potential thermal hazard associated with its decomposition, a nonisothermal DSC experiment and an ARC test were conducted. For the acquisition of more precise thermal decomposition kinetic parameters, the impact of various crucible types on the experimental outcomes was scrutinized.

Leveraging Electron Push-Pull Effect for Catalytic Polymerization and Degradation of a Cyclobutane Monomer System.

Ring-opening polymerization (ROP) offers a striking solution to solve problems encountered in step-growth condensation polymerization, including precise control over molecular weight, molecular weight distribution, and topology. This has inspired our interest in ROP of cycloalkanes with an ultimate goal to rethink polyolefins, which clearly poses a number of challenges. Practicality of ROP of cycloalkanes is actually limited by their low polymerizability and elusive mechanisms which arise from significantly varied ring size and non-polar C-C bonds in monomers.

Design and preparation of fluorescent covalent organic frameworks for biological sensing.

Covalent organic frameworks (COFs) are a new class of functional solids featuring several fantastic structural characteristics, including a great diversity of building units and cross-linking patterns, precise integration of building blocks, and adjustable topology of porous architecture. In addition to the above features, some COF samples are constructed with high-density conjugated fragments, which have unique potential advantages in fluorescence imaging, and thus may have great potential applications in bioimaging. Herein, this article summarizes the recent progress in the design and preparation of fluorescent covalent organic frameworks.

Endoscopic therapy versus esophagectomy for T1bN0M0 esophageal cancer: A population-based study using propensity score matching.

Background: Endoscopic therapy is an optional strategy for the treatment of esophageal cancer (EC) under an early stage, especially stage T1a. However, its efficacy in the treatment of T1b EC has not been thoroughly assessed. We investigated the efficacy of esophagectomy, endoscopic therapy, as well as chemoradiotherapy in patients with T1bN0M0 EC.

Simulation of thermal hazards risk in octogen based on non-isothermal DSC data.

To evaluate the possible thermal risks associated with the storage of octogen (HMX), non-isothermal differential scanning calorimetry (DSC) experiments were conducted in order to ascertain the kinetic model and parameters governing its thermal decomposition. DSC measurements indicate that HMX underwent a crystal transformation prior to thermal decomposition. A kinetic model for the autocatalytic thermal decomposition process was developed through the analysis of its primary exothermic peaks.

ReaLigands: A Ligand Library Cultivated from Experiment and Intended for Molecular Computational Catalyst Design.

Computational catalyst design requires identification of a metal and ligand that together result in the desired reaction reactivity and/or selectivity. A major impediment to translating computational designs to experiments is evaluating ligands that are likely to be synthesized. Here, we provide a solution to this impediment with our ReaLigands library that contains >30,000 monodentate, bidentate (didentate), tridentate, and larger ligands cultivated by dismantling experimentally reported crystal structures.

Skeleton engineering of rigid covalent organic frameworks to alter the number of binding sites for improved radionuclide extraction.

Crystalline porous covalent frameworks (COFs) have been considered as a platform for uranium extraction from seawater and nuclear waste. However, the role of rigid skeleton and atomically precise structures of COFs is often ignored in the design of defined binding configuration. Here, a COF with an optimized relative position of two bidentate ligands realizes full potential in uranium extraction.

Glucose-activatable insulin delivery with charge-conversional polyelectrolyte multilayers for diabetes care.

One of the most effective treatments for diabetes is to design a glucose-regulated insulin (INS) delivery system that could adjust the INS release time and rate to reduce diabetes-related complications. Here, mixed multiple layer-by-layer (mmLbL)-INS microspheres were developed for glucose-mediated INS release and an enhanced hypoglycemic effect for diabetes care. To achieve ultrafast glucose-activated INS release, glucose oxidase (GOx) was assembled with a positively charged polymer and modified on INS LbL.

C-H Insertion in Dirhodium Tetracarboxylate-Catalyzed Reactions despite Dynamical Tendencies toward Fragmentation: Implications for Reaction Efficiency and Catalyst Design.

Rh-catalyzed C-H insertion reactions to form β-lactones suffer from post-transition state bifurcations, with the same transition states leading to ketones and ketenes via fragmentation in addition to β-lactones. In such a circumstance, traditional transition state theory cannot predict product selectivity, so we employed molecular dynamics simulations to do so and provide a framework for rationalizing the origins of said selectivity. Weak interactions between the catalyst and substrate were studied using energy decomposition and noncovalent interaction analyses, which unmasked an important role of the 2-bromophenyl substituent that has been used in multiple β-lactone-forming C-H insertion reactions.

Cu(II) carboxylate arene C─H functionalization: Tuning for nonradical pathways.

We report carbon-hydrogen acetoxylation of nondirected arenes benzene and toluene, as well as related functionalization with pivalate and 2-ethylhexanoate ester groups, using simple copper(II) [Cu(II)] salts with over 80% yield. By changing the ratio of benzene and Cu(II) salts, 2.4% conversion of benzene can be reached.

The influence of temperature environmental on performance of HNIW/FOX-7 based PBXs.

During application, energetic materials may suffer different temperature environmental stimulation. In order to study the influence of temperature environmental on performance of HNIW/FOX-7 based PBXs, HNIW/FOX-7 based PBX modeling powders and PBX columns were treated by LT (low temperature), HT (high temperature), HLC (high-low temperature cycle) and HLS (high-low temperature shock). Then scanning electron microscope (SEM), infrared spectra (IR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to study the variation of PBX modeling powders after LT, HT, HLC and HLS treatments; in addition, the mass, size and mechanical properties of PBX columns were characterized after different temperature adaptability treatments as well.

PD-L1 Expression and Intra-Tumoral CD8 T Lymphocytes in Esophageal Carcinosarcoma.

We detected PD-L1 and intra-tumoral CD8 T lymphocytes (CD8 TIL) in 19 patients with esophageal carcinosarcoma (ECS). The median follow-up period of these patients was 43 months, and the three- and five-year survival rates were 78.9 and 63.

Rapid Removal of Mercury from Water by Novel MOF/PP Hybrid Membrane.

Mercury is one of the most toxic heavy metals that can cause terrible disease for human beings. Among different absorption materials, MOF (metal-organic framework) materials show potential as very attractive materials for the rapid removal of mercury. However, the instability and difficulty for regeneration of MOF crystals limit their applications.

Theory and Experiment Demonstrate that Sb(V)-Promoted Methane C-H Activation and Functionalization Outcompete Superacid Protonolysis in Sulfuric Acid.

Sb(V) in strong Brønsted acid solvents is traditionally assumed to react with light alkanes through superacid protonolysis, which results in carbocation intermediates, H, and carbon oligomerization. In contrast to this general assumption, our density functional theory (DFT) calculations revealed an accessible barrier for C-H activation between methane and Sb(V) in sulfuric acid that could potentially outcompete superacid protonolysis. This prompted us to experimentally examine this reaction in sulfuric acid with oleum, which has never been reported because of presumed superacid reactivity.

Esophageal Carcinosarcoma: Analysis of Clinical Features and Prognosis of 24 Cases and a Literature Review.

Objective: Esophageal carcinosarcoma (ECS) is a rare malignant tumor that accounts for only 0.5%-2.8% of all esophageal malignancies.