Oxidized Carbon Nitrides: Water‐Dispersible,Atomically Thin Carbon Nitride‐Based Nanodots and Their Performances as Bioimaging Probes

Three‐dimensional (3D) carbon nitride (C₃N₄)‐based materials show excellent performance in a wide range of applications because of their suitable band structures. To realize the great promise of two‐dimensional (2D) allotropes of various 3D materials, it is highly important to develop routes for the production of 2D C₃N₄ materials, which are one‐atom thick, in order to understand their intrinsic properties and identify their possible applications. In this work, water‐dispersible, atomically thin, and small carbon nitride nanodots were produced using the chemical oxidation of graphitic C₃N₄. Various analyses, including X‐ray diffraction, X‐ray photoelectron, Fourier‐transform infrared spectroscopy, and combustion‐based elemental analysis, and thermogravimetric analysis, confirmed the production of 3D oxidized C₃N₄ materials. The 2D C₃N₄ nanodots were successfully exfoliated as individual single layers; their lateral dimension was several tens of nanometers. They showed strong photoluminescence in the visible region as well as excellent performances as cell‐imaging probes in an in vitro study using confocal fluorescence microscopy.     

Heterobimetallic Cluster-Based Coordination Polymers: Assembly,Structures and Third-Order Nonlinear Optical Properties

Reactions of (NH₄)₂WS₄ with CuCN, CuCN/1,2-bis(4-pyridyl)propane (bppa) or [Cu(MeCN)₄]PF₆/bppa under different reaction conditions afforded a set of two- or three-dimensional W/Cu/S cluster-based coordination polymers including {[Et₄N]₂[WS₄Cu₄(μ-CN)₂(μ-I)₂]}_n ( 1 ), [WS₄Cu₄(μ-CN)₂(bppa)₂]_n ( 2 ) and {[WS₄Cu₄(bppa)₄](PF₆)₂}_n ( 3 ), respectively. Compound 2 can be readily formed from reaction of 1 with bppa under solvothermal conditions. Compounds 1 and 2 feature two-dimensional networks with a “sql” topology, while 3 possesses a two-fold interpenetrated three-dimensional net with a rare “reo” topology. Compounds 1 – 3 in DMF exhibited different third-order nonlinear optical responses, and they all showed a reverse saturable absorption while 2 held a strong self-focusing effect.     

Non‐Pyrolytic,Large‐Scale Synthesis of Trichalcogenasumanene: A Two‐Step Approach

Trichalcogenasumanenes were synthesized on a multigram scale through a two‐step approach that takes advantage of non‐pyrolytic cyclization and solventless ring contraction. Solid‐state structure and photophysical investigations demonstrate that these compounds are promising candidates for electronic materials.     

Cobimetinib 消旋体的合成

以3-羟基氮杂环丁烷盐酸盐为原料,经Cbz保护和氧化反应制得1 苄氧羰基氮杂环丁烷-3-酮(3); 3与N-亚硝基哌啶发生亲核反应后与2,3-二氟-(2-氟-4-碘氨基）苯甲酸发生缩合反应,最后经氯化氢脱亚硝基和碱化合成了Cobimetinib消旋体,其结构经¹H NMR和HR-MS（ESI）确证。     

Tailoring thermal conductivity of bulk graphene oxide by tuning the oxidation degree

The thermal conductivity of graphene oxides can be tailored by tuning oxidation degree due to the introduction of atomic- and nano-scale phonon scattering centers.     

The Influence of Space Restriction on the Mechanical Properties of Isotactic Polypropylene/Reduced Graphene Oxide Nanocomposite Injection Bars

Isotactic polypropylene (iPP)/reduced graphene oxide (RGO) nanocomposite bars were prepared by injection molding and the effects of RGO on the iPP matrix were investigated via differential scanning calorimetry, two dimensional wide angle X-ray diffraction (2D WAXD) and small angle X-ray scattering (2D SAXS) techniques. It is demonstrated that RGO is an effective nucleation agent for iPP and the incorporation of RGO can enhance the degree of orientation of iPP crystals at flow direction. Furthermore, the orientation of iPP chains at flow direction intensifies with the increase of RGO contents, which can be attributed to that RGO obstructed the motion of orientated polymer chains. Although the enhancement effect is weaker than that of High density polyethylene (HDPE)/RGO nanocomposites with epitaxial crystallization, the mechanical properties of iPP/RGO nanocomposites can also be improved apparently.     

Ultrasensitive amperometric aptasensor for the epithelial cell adhesion molecule by using target-driven toehold-mediated DNA recycling amplification

An amperometric aptasensor is reported for the electrochemical determination of the epithelial cell adhesion molecule (EpCAM). It is based on a combination of EpCAM-driven toehold-mediated DNA recycling amplification, the specific recognition of EpCAM aptamer, and its binding to EpCAM. Hairpin probe 1 (Hp1) with a toehold region was modified with a 5′-thiol group (5’-SH) and self-assembled onto the surface of a gold electrode. Upon addition of EpCAM, the probe A (a 15-mer) is liberated from the aptamer/probe A complex and then hybridizes with the toehold domain of Hp1. This results in the exposure of another toehold for further hybridizing with hairpin probe 2 (Hp2) to displace probe A in the presence of Hp2 that was labeled with the electrochemical probe Methylene Blue (MB). Subsequently, liberated probe A is hybridized again with another Hp1 to start the next round of DNA recycling amplification by reusing probe A. This leads to the formation of plenty of MB-labeled DNA strands on the electrode surface and generates an amplified current. This 1:N probe-response amplification results in ultrasensitive and specific detection of EpCAM, with a 20 pg·mL^?1 detection limit. The electrode is highly stable and regenerable. It was successfully applied to the determination of EpCAM in spiked human serum, urine and saliva, and thus provides a promising tool for early clinical diagnosis.

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Graphical abstract Schematic illustration of the electrochemical detection for EpCAM. The method is based on aptamer-based recognition and EpCAM-driven toehold-mediated DNA recycling amplification. Hp1: Hairpin probe 1; Hp2: Hairpin probe 2; MB: Methylene blue; MCH: 6-Mercapto-1-hexanol; EpCAM: Epithelial cell adhesion molecule.

     

Lymphatic targeting of hematoporphyrin monomethyl ether using poly (butyl-cyanoacrylate) based nanoparticle drug delivery system

The traditional treatment has inevitable drawbacks of nonspecific lymph targeting, poor therapeutic efficiency and residual metastatic for advanced cancer patients with lymph node metastases. To overcome these shortcomings, we prepare a nano-carrier drug delivery system. Photosensitizer hematoporphyrin monomethyl ether (HMME)-loaded poly (n-butylcyanoacrylate) nanoparticles (PBCA-NPs) was prepared successfully. The particle size was approximately 160 nm, the envelopment rate was 87.9%, and the drug loading rate was about 13.4%. The drug release study in vitro showed that the cumulative release rates of HMME-PBCA-NPs group was much less than free HMME group. The drug distribution in different tissues showed that the peak-reach time was 3 h in free HMME group and 6 h in nanoparticles group. All of these results confirmed the slow release characteristic of nanoparticles. In lymph node tissues, the HMME concentrations in HMME-PBCA-NPs group were much higher than those of the free HMME group at any time points we tested, in which the maximum difference concentration of HMME appeared at 6 h (1.2884?±?0.04695 vs. 0.0438?±?0.00558 µg/mg) after drug delivery. The mesenteric lymph nodes of rabbits were enlarged obviously in the NP group than in free HMME group at 6 h after drug delivery. All of these results confirmed the slow release characteristic and the lymphatic targeting characteristic of nanoparticles. In summary, we developed a lymphatic targeting nanoparticles drug delivery system successfully, which showed perfect lymph targeting and has the potential to be a new therapy strategy for advanced cancer patients with lymph node metastasis.     

Chemistry of Metallacyclobutadienes

Metallacyclobutadienes are analogues of cyclobutadienes in which one of the cyclobutadiene CR groups has been formally replaced by a transition‐metal fragment. These metallacycles are interesting because they can play an important role in catalysis and can serve as starting materials for the syntheses of organometallic compounds such as metallabenzene, η⁵‐cyclopentadienyl, and η³‐cyclopropenyl complexes. Unlike cyclobutadienes, metallacyclobutadienes can be significantly more stable. A number of metallacyclobutadienes have now been isolated and thoroughly characterized, especially for those that contain transition metals of groups 5–9. Their properties have also been actively investigated. This article highlights the chemistry of metallacyclobutadienes with reference to their syntheses, reactivity, and structural properties.     

Hierarchical MoS2@TiO2 Heterojunctions for Enhanced Photocatalytic Performance and Electrocatalytic Hydrogen Evolution

Hierarchical MoS₂@TiO₂ heterojunctions were synthesized through a one‐step hydrothermal method by using protonic titanate nanosheets as the precursor. The TiO₂ nanosheets prevent the aggregation of MoS₂ and promote the carrier transfer efficiency, and thus enhance the photocatalytic and electrocatalytic activity of the nanostructured MoS₂. The obtained MoS₂@TiO₂ has significantly enhanced photocatalytic activity in the degradation of rhodamine B (over 5.2 times compared with pure MoS₂) and acetone (over 2.8 times compared with pure MoS₂). MoS₂@TiO₂ is also beneficial for electrocatalytic hydrogen evolution (26 times compared with pure MoS₂, based on the cathodic current density). This work offers a promising way to prevent the self‐aggregation of MoS₂ and provides a new insight for the design of heterojunctions for materials with lattice mismatches.