Study of fragmentation pathways of lithiated α,β‐unsaturated thioesters by electrospray ionization mass spectrometry

The fragmentation pathways of lithiated α,β‐unsaturated thioesters with different substituents were investigated by electrospray ionization tandem mass spectrometry (ESI‐MS/MS) in positive ion mode. In mass spectrometry of the α,β‐unsaturated thioesters, Ar‐CH?CH‐CO‐S‐Ph, loss of PhSLi and elimination of a thiophenol were the two major fragmentation reactions of the lithiated molecules. The elemental compositions of all the ions were confirmed by high‐resolution Fourier transform ion cyclotron resonance tandem mass spectrometry (FTICR‐MS/MS). The thioesters studied here were para‐monosubstituted on the phenyl ring of cinnamoyl and the electron‐withdrawing groups favored loss of a thiophenol, whereas the electron‐releasing groups strongly favored the competing reaction leading to the loss of PhSLi to form a cinnamoyl cation, Ar‐CH?CHCO⁺. The intensity ratios of the two competitive product ions were well correlated with the σ substituent constants. The mechanisms of these two competing routes were further investigated by density functional theory (DFT) calculations. Copyright © 2010 John Wiley & Sons, Ltd.     

Direct mass measurements of short-lived A=2Z-1 nuclides (63)Ge, (65)As, (67)Se, and (71)Kr and their impact on nucleosynthesis in the rp process

Mass excesses of short-lived A=2Z-1 nuclei (63)Ge, (65)As, (67)Se, and (71)Kr have been directly measured to be -46,921(37), -46,937(85), -46,580(67), and -46,320(141) keV, respectively. The deduced proton separation energy of -90(85) keV for (65)As shows that this nucleus is only slightly proton unbound. X-ray burst model calculations with the new mass excess of (65)As suggest that the majority of the reaction flow passes through (64)Ge via proton capture, indicating that (64)Ge is not a significant rp-process waiting point.     

Chirality-assisted electronic cloaking of confined States in bilayer graphene

We show that the strong coupling of pseudospin orientation and charge carrier motion in bilayer graphene has a drastic effect on transport properties of ballistic p-n-p junctions. Electronic states with zero momentum parallel to the barrier are confined under it for one pseudospin orientation, whereas states with the opposite pseudospin tunnel through the junction totally uninfluenced by the presence of confined states. We demonstrate that the junction acts as a cloak for confined states, making them nearly invisible to electrons in the outer regions over a range of incidence angles. This behavior is manifested in the two-terminal conductance as transmission resonances with non-Lorentzian, singular peak shapes. The response of these phenomena to a weak magnetic field or electric-field-induced interlayer gap can serve as an experimental fingerprint of electronic cloaking.     

Carbon cloth supported lithiophilic carbon nanotubes@Ag skeleton for lithium anode via ultrafast Joule heating method

Journal of Solid State Electrochemistry - Regulating lithium deposition and stripping behavior during cycles is critical for constructing high-performance and stable lithium metal anodes (LMAs)....     

High-Pressure Fabrication of Binary Organic Solar Cells with High Molecular Weight D18 Yields Record 19.65 % Efficiency

In this work, inspired by the principles of a pressure cooker, we utilized a high-pressure method to address the processing challenges associated with high molecular weight polymers. Through this approach, we successfully dissolved high molecular weight D18 in chloroform at 100 °C within a pressure-tight vial. The increased steam pressure raised the boiling point and dissolving capacity of chloroform, enabling the creation of a hybrid film with superior properties, including more ordered molecular arrangement, increased crystallinity, extended exciton diffusion length, and improved phase morphology. Organic solar cells (OSCs) based on D18 : L8-BO prepared using this high-pressure method achieved an outstanding power conversion efficiency of 19.65 %, setting a new record for binary devices to date. Furthermore, this high-pressure method was successfully applied to fabricate OSCs based on other common systems, leading to significant enhancements in device performance. In summary, this research introduces a universal method for processing high molecular weight D18 materials, ultimately resulting in the highest performance reported for binary organic solar cells.     

Hemin-Promoted Direct C−H Thiolation in the Synthesis of Diaryl Sulfides

Diaryl sulfides are a class of important synthetic chemical units. Herein, we report a new method for direct preparation of diphenyl sulfides using P-toluenesulfonyl chloride as an effective thiophenyl radical precursor with assistance from Hemin. Various substituted anisoles and benzenesulfonyl chlorides are well tolerated, resulting in moderate to good yields of diaryl sulfides. The potential of the proposed method is validated by good yields obtained in gram scale reactions.     

Protein-Targeted Glycan Editing on Living Cells Disrupts KRAS Signaling

The frequent mutation of KRAS oncogene in some of the most lethal human cancers has spurred incredible efforts to develop KRAS inhibitors, yet only one covalent inhibitor for the KRAS^G12C mutant has been approved to date. New venues to interfere with KRAS signaling are desperately needed. Here, we report a “localized oxidation-coupling” strategy to achieve protein-specific glycan editing on living cells for disrupting KRAS signaling. This glycan remodeling method exhibits excellent protein and sugar specificity and is applicable to different donor sugars and cell types. Attachment of mannotriose to the terminal galactose/N-acetyl-D-galactosamine epitopes of integrin α_vβ₃, a membrane receptor upstream of KRAS, blocks its binding to galectin-3, suppresses the activation of KRAS and downstream effectors, and mitigates KRAS-driven malignant phenotypes. Our work represents the first successful attempt to interfere with KRAS activity by manipulating membrane receptor glycosylation.     

Maldistribution of Chemical Bond Strength Inducing Exceptional Anisotropy of Thermal Conductivity in Non-Layered Materials

Currently, the efforts to find materials with high κ anisotropy ratios mainly focus on layered materials, however, the limited quantity and lower workability comparing to non-layered ones boost the exploration of non-layered materials with high κ anisotropy ratios. Here, taking PbSnS₃, a typical non-layered orthorhombic compound, as an example, we propose that maldistribution of chemical bond strength can lead to large anisotropy of κ in non-layered materials. Our result reveals that the maldistribution of Pb−S bonds lead to obvious collective vibrations of dioctahedron chain units, resulting in an anisotropy ratio up to 7.1 at 200 K and 5.5 at 300 K, respectively, which is one of the highest ever reported in non-layered materials and even surpasses many classical layered materials such as Bi₂Te₃ and SnSe. Our findings can not only broaden the horizon for exploring high anisotropic κ materials but also provide new opportunities for the application of thermal management.