Photo‐Induced Carbonylation of Aryl Bromides for the Synthesis of Aryl Esters and Amides Under Transition Metal‐Free Conditions

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Photo-Induced Carbonylation of Aryl Bromides for the Synthesis of Aryl Esters and Amides Under Transition Metal-Free Conditions

A photo-induced metal-free carbonylation reaction of aryl bromides has been developed. The method shows good reactivity with alcohol and amine nucleophiles, and a variety of useful aryl esters and amides were synthesized at room temperature in moderate to good yields.


Abstract

In this work, we developed a photo-induced carbonylation of aryl bromides under transition metal-free conditions. The reaction shows good activity with alcohol and amine nucleophiles. Various esters and amides were formed from aryl halides and alcohols and amines under mild conditions in moderate to good yields.

Creation of a Highly Active Small Cu‐Based Catalyst Derived from Copper Aluminium Layered Double Hydroxide Supported on α‐Al2O3 for Acceptorless Alcohol Dehydrogenation

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Creation of a Highly Active Small Cu-Based Catalyst Derived from Copper Aluminium Layered Double Hydroxide Supported on α-Al2O3 for Acceptorless Alcohol Dehydrogenation

A highly reducible CuO with a small size was created by calcination of carbonate-intercalated Cu2+-Al3+ layered double hydroxide (CuAl LDH) on the surface of α-Al2O3 (CuAl LDH@α-Al2O3). Synthesised CuAlO@α-Al2O3 catalyst was highly active for the acceptorless dehydrogenation of various alcohols. CuO species in the catalyst matrix smoothly reduced into catalytically active Cu0 during reaction without separate reduction procedure.


Abstract

A highly dispersed carbonate-intercalated Cu2+-Al3+ layered double hydroxide (CuAl LDH) was created on an unreactive α-Al2O3 surface (CuAl LDH@α-Al2O3) via a simple coprecipitation method of Cu2+ and Al3+ under alkaline conditions in the presence of α-Al2O3. A highly reducible CuO nanoparticles was generated, accompanied by the formation of CuAl2O4 on the surface of α-Al2O3 (CuAlO@α-Al2O3) after calcination at 1073 K in air, as confirmed by powder X-ray diffraction (XRD) and Cu K-edge X-ray absorption near edge structure (XANES). The structural changes during the progressive heating process were monitored by using in-situ temperature-programmed synchrotron XRD (tp-SXRD). The layered structure of CuAl LDH@α-Al2O3 completely disappeared at 473 K, and CuO or CuAl2O4 phases began to appear at 823 K or 1023 K, respectively. Our synthesised CuAlO@α-Al2O3 catalyst was highly active for the acceptorless dehydrogenation of benzylic, aliphatic, or cyclic aliphatic alcohols; the TON based on the amount of Cu increased to 163 from 3.3 of unsupported CuAlO catalyst in 1-phenylethanol dehydrogenation. The results suggested that Cu0 was obtained from the reduction of CuO in the catalyst matrix during the reaction without separate reduction procedure and acted as a catalytically active species.

Nitrogen Atom Induced Contrast Effect on the Mechanofluorochromic Characteristics of Anthracene‐Based Acceptor‐Donor‐Acceptor Fluorescent Molecules

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Nitrogen Atom Induced Contrast Effect on the Mechanofluorochromic Characteristics of Anthracene-Based Acceptor-Donor-Acceptor Fluorescent Molecules

Six anthracene-based A−D−A fluorescent compounds were synthesized through precise modulation of number and arrangement of nitrogen atoms. Comprehensive investigation of the photophysical properties of these six molecular structures was conducted both in solution and solid phases. Notably, all six compounds exhibited distinct mechanofluorochromic characteristics within the solid-state.


Abstract

The mechanofluorochromic (MFC) characteristics of anthracene-based acceptor-donor-acceptor (A−D−A) fluorescent molecules are explored through a comprehensive investigation of their photophysical behaviors. Six 9,10-diheteroarylanthracene derivatives with varying acceptor groups (pyridin-4-yl, pyridin-3-yl, pyridin-2-yl, pyrimidin-5-yl, pyrazinyl and quinoxalinyl) are synthesized and systematically characterized. The photophysical properties in both solution and solid-state are examined, revealing subtle yet significant influences of the spatial arrangement and number of nitrogen atoms within the acceptor group on fluorescence emission. Single-crystal structures of these compounds provide insights into their steric configurations and intermolecular packing modes, offering valuable insights into the fundamental mechanisms that underlie the observed MFC properties. This study illuminates the intricate interplay between MFC properties and the refined molecular structure, thus presenting promising avenues for the design and advancement of novel MFC materials.

Near‐infrared Fluorescent Probes with Long‐acting Cyclic Monitoring and Effectively Eliminating Peroxynitrite

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Near-infrared Fluorescent Probes with Long-acting Cyclic Monitoring and Effectively Eliminating Peroxynitrite

A long-acting cyclic and near-infrared fluorescent probe was synthesized for monitoring peroxynitrite (ONOO−). The fluorescence intensity at 652 nm rapidly changes in response to the sensing and eliminating processes for ONOO−. This is the first probe with multiple functions including real-time detection, long-acting monitoring and in-situ elimination, which helps to maintain the physiological balance of ONOO−.


Abstract

Two through-bond energy transfer fluorescent probes with a dihydroxyl naphthyl-pyrenyl conjugated system were synthesized for long-acting cyclic monitoring and eliminating peroxynitrite (ONOO−). The probes exhibit large Stokes shifts (230 or 280 nm) and the fluorescence at 620 or 652 nm rapidly change in response to continuously variable concentrations of ONOO− under physiological conditions. The probes show good reversibility and can rapidly monitor the concentration changes of ONOO− in real time. In addition, with the additions of the probes, the decomposition of ONOO− is greatly accelerated. Therefore, the probes can effectively eliminate the excess ONOO− as well as sensing it. The biological studies showed that the probes can effectively and reversibly eliminate both exogenous and endogenous ONOO− in-situ as well as sensing its changes in cells, which can help to maintain the normal physiological concentration of ONOO− in organisms. This is the first system that a probe achieves multifunction including real-time detection, long-acting cyclic monitoring and in-situ elimination, thereby maintaining a normal physiological balance for ONOO−.

Organometallic Reagents: Efficient Tools for the Synthesis of Fused Pyridinyl‐Lactones

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Organometallic Reagents: Efficient Tools for the Synthesis of Fused Pyridinyl-Lactones

Through the development of a one pot synthesis of fused substituted heteroaryl-lactones involving a Metal/Halogen Exchange reaction as key step, the reactivity of various mono- or bimetallic reagents (organolithiums, Grignard reagents and lithium organomagnesiate complexes) was explored to aim high chemoselectivity and efficiency starting from sensitive substrates.


Abstract

Herein we disclose an efficient one-pot route to a wide range of 3-substituted fused pyridinyl-lactones, so called aza-phthalides. The developed strategy involves a Metal/Halogen Exchange (MHE) reaction as key step, followed by an electrophile trapping using various carbonyl derivatives and a subsequent lactonization. To promote the MHE reaction with high chemoselectivity, our investigations have particularly focused on the nature of mono- or bimetallic derivatives as metalation reagents including organolithiums, Grignard reagents and lithium organomagnesiate complexes, and highlighted the positive salt effect on reactional sequence. An extension to fused heteroaryl-lactones (benzothienyl-, benzofuranyl- and naphthofuranyl scaffolds) was explored.

Recent Advances in Polyoxometalate Based Nanoplatforms Mediated Reactive Oxygen Species Cancer Therapy

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Recent Advances in Polyoxometalate Based Nanoplatforms Mediated Reactive Oxygen Species Cancer Therapy

The potential mechanism of reactive oxygen species (ROS) generation by polyoxometalate (POM) in tumor microenvironment (TME), as well as the different manners of ROS-mediated cell death, were discussed from the perspective of chemical reaction and biological progress. Furthermore, endogenous/exogenous stimuli interact with POM to modulate ROS is summarized.


Abstract

The potential of reactive oxygen species (ROS) cancer therapy in tumor treatment has been greatly enhanced by the introduction of catalytically superior polyoxometalate (POM)-based nanoplatforms, mainly composed of atomic clusters consisting of pre-transition metals and oxygen. These nanoplatforms have unique advantages, such as Fenton activity at neutral pH, induction of cellular ferroptosis instead of just apoptosis, and sensitivity to external field stimulation. However, there are also inevitable challenges such as neutralization of ROS by the antioxidant system of the tumor microenvironment (TME), hypoxia, and limited hydrogen peroxide concentrations. This review article aims to provide an overview of recent research advancements in POM-based nanoplatforms for ROS therapy from the perspective of chemical reactions and biological processes, addressing endogenous and exogenous factors that affect the antitumor efficacy. Endogenous factors include the mechanism of ROS generation by POM, the impact of pH and antioxidant systems on POM, and the various manners of tumor cell death. Exogenous stimuli mainly include light, heat, X-rays, and electricity. The article analyzes the specific mechanisms of action of each influencing factor in the first two sections, concluding with the limitations of the present study and some possible directions for future research.

Rational Design of Tunable Near‐Infrared Oxazine Probe with Large Stokes Shift for Leucine Aminopeptidase Detection and Imaging

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Rational Design of Tunable Near-Infrared Oxazine Probe with Large Stokes Shift for Leucine Aminopeptidase Detection and Imaging

A novel amino-tunable near-infrared oxazine dye (DQF-NH2) with large Stokes shift (125 nm) has been designed by a molecular integration strategy of optically tunable groups and unsymmetric oxazine fluorophore. As an example of its application, we use this NIR dye to develop a highly sensitive fluorescent probe DQF-NH2-LAP for detecting and imaging leucine aminopeptidase in living cells and in vivo.


Abstract

Near-Infrared (NIR) fluorescence imaging with the advantages of deep tissue penetration and minimum background, has been widely employed and developed in the study of biological applications. However, small Stokes shifts, difficulty in optical tuning, and pH sensitivity are still the major limitations faced by current NIR dyes. To solve these problems, we rationally designed a pH insensitive amino-tunable NIR oxazine fluorophore DQF-NH2 , which exhibited large Stokes shift (125 nm) accompanied with NIR excitation/emission due to the introduction an asymmetrical alternating vibronic feature. By benefiting from the excellent photophysical properties of DQF-NH2 , we have successfully constructed the probe DQF-NH2-LAP with the ability to detect endogenous LAP. Bioimaging assays demonstrated that DQF-NH2-LAP can not only effectively detect LAP in living cells, but also was successfully applied to image tumor tissue in vivo. We anticipate that the functionalizable dye DQF-NH2 may be a potential new NIR dye platform with an optically tunable group for the development of future desirable probes for bioimaging.

Production of 2,5‐Furandicarboxylic Acid Methyl Esters from Pectin‐Based Aldaric Acid: from Laboratory to Bench Scale

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Production of 2,5-Furandicarboxylic Acid Methyl Esters from Pectin-Based Aldaric Acid: from Laboratory to Bench Scale

The synthesis and purification of pectin-based 2,5-furandicarboxylic acid methyl esters from gram-scale to kilogram-scale enables the valorisation of agricultural side streams into fully renewable polyesters.


Abstract

2,5-Furandicarboxylic acid (FDCA) is one of the most attractive emerging renewable monomers, which has gained interest especially in polyester applications, such as the production of polyethylene furanoate (PEF). Recently, the attention has shifted towards FDCA esters due to their better solubility as well as the easier purification and polymerisation compared to FDCA. In our previous work, we reported the synthesis of FDCA butyl esters by dehydration of aldaric acids as stable intermediates. Here, we present the synthesis of FDCA methyl esters in high yields from pectin-based galactaric acid using a solid acid catalyst. The process enables high substrate concentrations (up to 20 wt %) giving up to 50 mol % FDCA methyl esters with total furancarboxylates yields of up to 90 mol %. The synthesis was successfully scaled up from gram-scale to kilogram-scale in batch reactors showing the feasibility of the process. The stability of the catalyst was tested in re-use experiments. Purification of the crude product by vacuum distillation and precipitation gave furan-2,5-dimethylcarboxylate with a 98 % purity.

Stabilizing Decavanadate Cluster as Electrode Material in Sodium and Lithium‐ion Batteries

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Stabilizing Decavanadate Cluster as Electrode Material in Sodium and Lithium-ion Batteries

The decavanadate cluster ([V10O28]6−) is stabilized with the organic guanidinium (CN3H6 +, Gdm+) cation through electrostatic and hydrogen bonding interactions. The resulting Gdm{V10} cluster shows improved thermal properties and stability in liquid organic electrolytes, leading to better performance as an anode material for sodium-ion and lithium-ion batteries.


Abstract

Decavanadate ([V10O28]6−, {V10}) clusters are a potential electrode material for lithium and post-lithium batteries; however, their low stability due to the solubility in liquid organic electrolytes has been challenging. These molecular clusters are also prone to transform into solid-state oxides at a moderate temperature needed in the typical electrode fabrication process. Hence, controlling the solubility and improving the thermal stability of compounds are essential to make them more viable options for use as battery electrodes. This study shows a crystal engineering approach to stabilize the cluster with organic guanidinium (Gdm+) cation through the hydrogen-bonding interactions between the amino groups of the cation and the anion. The comparison of solubility and thermal stability of the Gdm{V10} with another cluster bearing tetrabutylammonium (Tba+) cation reveals the better stability of cation-anion assembly in the former than the latter. As a result, the Gdm{V10} delivers better rate capability and cycling stability than Tba{V10} when tested as anode material in a half-cell configuration of a sodium-ion battery. Finally, the performance of the Gdm{V10} anode is also investigated in a lithium-ion battery full cell with LiFePO4 cathode.

Thermal‐Conductivity‐Enhancing Copper‐Plated Expanded Graphite/Paraffin Composite for Highly Stable Phase‐Change Materials

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Thermal-Conductivity-Enhancing Copper-Plated Expanded Graphite/Paraffin Composite for Highly Stable Phase-Change Materials

Enhanced thermal conductive phase change materials are fabricated by introducing copper plated expanded graphite(CPEG)with 3D porous structure prepared by electroless copper plating method into PA/EG composite. The PA/EG/CPEG composites demonstrate remarkable thermal conductivity and temperature control effect on power lithium-ion batteries.


Abstract

Paraffin (PA)/expanded graphite (EG) is an important composite phase change material with low cost, high heat storage, good thermal conductivity and cycling stability. Its thermal conductivity needs to be further improved for application in the thermal management system of power lithium-ion batteries. In this paper, copper plated expanded graphite (CPEG) with 3D porous structure was prepared by electroless copper plating method, which was used as thermal conductivity enhancing material to replace part of EG in PA/EG composite materials. For the optimized phase change material composed of 80 %PA-14 %EG-6 %CPEG, the copper content is very low (0.768 wt %), but its thermal conductivity can be significantly improved without loss of latent heat and thermal cycling stability. Its thermal conductivity is increased from 11 times to 16.5 times that of paraffin while compared with the copper-free composite material (80 %PA-20 %EG). The PA/EG/CPEG composite material exhibits good temperature control effect on power lithium-ion batteries.