Activity

Evidence is provided that the key NCI in the major pathway is a π-stacking interaction, contrasting with the cation-π interactions invoked in previously studied reactions promoted by the same family of aryl-pyrrolidino-H-bond-donor catalysts.The elaborate interface interactions can be critical in determining the achievable functionality of a semiconductor heterojunction (SH), particularly when two-dimensional material is enclosed in the system and its thickness is at an atomic extreme. In this work, we have successfully constructed a SH model system composed of typical transition-metal chalcogenide (TMDs) and transition metal oxides (TMO) by directly growing molybdenum sulfide (MoS2) nanosheets on atomically flat strontium titanate (SrTiO3) single crystal substrates through a conventional chemical vapor deposition (CVD) synthetic method. Multiple measurements have demonstrated the uniform monolayer thickness and single crystallinity of the MoS2 nanosheets as well as the atomic flatness of the heterojunction surface, both characterizing an extremely high quality of the interface. NPD4928 Clear evidence have been obtained for the electron transfer from the MoS2 adlayer to the SrTiO3 substrate which varies against the interface conditions. More importantly, the photoluminescence of MoS2 is significantly tailored, which is correlated with both the cleanness of the interface and the crystal orientation of the SrTiO3 substrate. These results not only shed fresh lights on the structure-property relationship of the TMDs/TMO heterostructures but also manifest the importance of the ideal interface structure for a hybridized system.Intramolecular alkoxylation of C-H bonds can rapidly introduce structural and functional group complexities into seemingly simple or inert precursors. The transformation is particularly important due to the ubiquitous presence of tetrahydrofuran (THF) motifs as fundamental building blocks in a wide range of pharmaceuticals, agrochemicals, and natural products. Despite the various synthetic methodologies known for generating functionalized THFs, most show limited functional group tolerance and lack demonstration for the preparation of spiro or fused bi- and tricyclic ether units prevalent in molecules for pharmacological purposes. Herein we report an intramolecular C-H alkoxylation to furnish oxacycles from easily prepared α-diazo-β-ketoesters using commercially available iron acetylacetonate (Fe(acac)2) as a catalyst. The reaction is proposed to proceed through the formation of a vinylic carboradical arising from N2 extrusion, which mediates a proximal H-atom abstraction followed by a rapid C-O bond forming radical recombination step. The radical mechanism is probed using an isotopic labeling study (vinyl C-D incorporation), ring opening of a radical clock substrate, and Hammett analysis and is further corroborated by density functional theory (DFT) calculations. Heightened reactivity is observed for electron-rich C-H bonds (tertiary, ethereal), while greater catalyst loadings or elevated reaction temperatures are required to fully convert substrates with benzylic, secondary, and primary C-H bonds. The transformation is highly functional group tolerant and operates under mild reaction conditions to provide rapid access to complex structures such as spiro and fused bi-/tricyclic O-heterocycles from readily available precursors.A novel umami peptide, IPIPATKT, showed excellent dual dipeptidyl peptidase-IV (DPP-IV) and angiotensin I-converting enzyme (ACE) inhibitory activities, the IC50 values were 64 and 265 μM, respectively. Molecular docking displayed that IPIPATKT was docked into the S1 and S2 pockets of ACE, and it was close to the active site pocket of DPP-IV. The insulin-resistant-HepG2 (IR-HepG2) cell model and human umbilical vein endothelial cell (HUVEC) model showed that the peptide significantly increased the content of glucose, the activities of hexokinase, pyruvate kinase, and the concentration of nitric oxide (p less then 0.01), while it reduced the content of endothelin-1 (ET-1). IPIPATKT exhibited a hypotensive effect (-23.5 ± 2.2 mmHg) and attenuated the increase in glucose levels in vivo, as demonstrated using spontaneous hypertensive rats (SHRs) and C57BL/6N mice. We reported the in vivo activities of the umami peptide with dual hypertensive and hypoglycemic effects for the first time.A new optimized ultraviolet (UV) technique induced a photooxidation surface modification on thin-film composite (TFC) polyamide (PA) brackish water reverse osmosis (BWRO) membranes that improved membrane performance (i.e., permeability and organic fouling propensity). Commercial PA membranes were irradiated with UV-B light (285 nm), and the changes in the membrane performance were assessed through dead-end and cross-flow tests. UV-B irradiation at 12 J·cm-2 enhanced the pure water permeability by 34% in the dead-end tests without decreasing the mono- or divalent ion rejections, as compared with the pristine PA membrane, and led to less fouling by natural organic matter in the cross-flow tests. Scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) confirmed that UV-B irradiation opened the pore structure and created carboxylic and amine groups on the PA surface, leading to increased membrane surface charge and hydrophilicity. Thus, an optimal UV-B dose appears to modify only a thin layer of the PA membrane surface, which favorably enhances the membrane performance. UV-B did not alter the structure, flux, or salt rejection for cellulose triacetate (CTA)-based membranes. While other membrane surface modifications include oxidants, strong acids, and bases, the UV-B facile treatment is chemical-free, thus reducing chemical wastes, and easy to apply in roll-to-roll fabrication processes of PA membranes. The results also showed that a low UV irradiation dose could be applied to PA or CTA membranes for disinfection or photocatalytic oxidation.A method for the acetoxyhydroxylation of olefins with syn stereoselectivity under electrophotocatalytic conditions is described. The procedure uses a trisaminocyclopropenium (TAC) ion catalyst with visible light irradiation under a controlled electrochemical potential to convert aryl olefins to the corresponding glycol monoesters with high chemo- and diastereoselectivity. This reaction can be performed in batch or in flow, enabling multigram synthesis of the monoester products.