Silver-Catalyzed Radical Aminofluorination of Unactivated Alkenes in Aqueous Media

We report herein a mild and catalytic intramolecular aminofluorination of unactivated alkenes. Thus, with the catalysis of AgNO₃, the reactions of various <i>N</i>-arylpent-4-enamides with Selectfluor reagent in CH₂Cl₂/H₂O led to the efficient synthesis of 5-fluoromethyl-substituted γ-lactams. A mechanism involving silver-catalyzed oxidative generation of amidyl radicals and silver-assisted fluorine atom transfer was proposed

Nickel-Catalyzed Reductive Dicarbofunctionalization of Alkenes

An intermolecular, three-component reductive dicarbofunctionalization of alkenes is presented here. The combination of Ni catalysis with TDAE as final reductant enables the direct formation of Csp³–Csp³ and Csp³–Csp² bonds across a variety of π-systems using two different electrophiles that are sequentially activated with exquisite selectivity under mild reaction conditions

Silver-Catalyzed Decarboxylative Fluorination of Aliphatic Carboxylic Acids in Aqueous Solution

Although fluorinated compounds have found widespread applications in the chemical and materials industries, general and site-specific C­(sp³)–F bond formations are still a challenging task. We report here that with the catalysis of AgNO₃, various aliphatic carboxylic acids undergo efficient decarboxylative fluorination with SELECTFLUOR^® reagent in aqueous solution, leading to the synthesis of the corresponding alkyl fluorides in satisfactory yields under mild conditions. This radical fluorination method is not only efficient and general but also chemoselective and functional-group-compatible, thus making it highly practical in the synthesis of fluorinated molecules. A mechanism involvinig Ag­(III)-mediated single electron transfer followed by fluorine atom transfer is proposed for this catalytic fluorodecarboxylation

Nitrogen Doped 3D Titanium Dioxide Nanorods Architecture with Significantly Enhanced Visible Light Photoactivity

Surface-reaction-limited pulsed chemical vapor deposition (SPCVD) is able to create 3D TiO₂-based hierarchical nanowire (NW) architecture with superhigh surface area and good electronic transport properties for high-performance photoelectrode development. However, how to intentionally dope the nanorods (NRs) through the SPCVD process to improve their electronic properties and light absorption behavior is still unexplored. In this paper, a comprehensive study of doping TiO₂ NRs with nitrogen through the SPCVD technique is reported for the first time. The high-density nitrogen doped TiO₂ NR branches with controlled doping concentrations were synthesized on dense Si NW forest by introducing designed number of TiN cycles to TiO₂ growth cycles. Microscopic studies revealed the influence of nitrogen doping on the crystal growth behavior and NR morphology, as well as the elements distribution inside the lattices. Nitrogen doping lowered the band gap of TiO₂ NRs and effectively activated visible light photoactivity. It also largely improved the incident-photon-to-current-conversion efficiency in the UV range. Successful synthesis of N doped TiO₂ NRs by the SPCVD method introduces a strong new capability to this novel and powerful 3D NR growth technique. It enables composition and optoelectronic property control of the novel 3D NR structures, allowing performance enhancement or creating new functionality

Silver-Catalyzed Decarboxylative Radical Azidation of Aliphatic Carboxylic Acids in Aqueous Solution

We report herein an efficient and general method for the decarboxylative azidation of aliphatic carboxylic acids. Thus, with AgNO₃ as the catalyst and K₂S₂O₈ as the oxidant, the reactions of various aliphatic carboxylic acids with tosyl azide or pyridine-3-sulfonyl azide in aqueous CH₃CN solution afforded the corresponding alkyl azides under mild conditions. A broad substrate scope and wide functional group compatibility were observed. A radical mechanism is proposed for this site-specific azidation

Silver-Catalyzed Decarboxylative Radical Azidation of Aliphatic Carboxylic Acids in Aqueous Solution

We report herein an efficient and general method for the decarboxylative azidation of aliphatic carboxylic acids. Thus, with AgNO₃ as the catalyst and K₂S₂O₈ as the oxidant, the reactions of various aliphatic carboxylic acids with tosyl azide or pyridine-3-sulfonyl azide in aqueous CH₃CN solution afforded the corresponding alkyl azides under mild conditions. A broad substrate scope and wide functional group compatibility were observed. A radical mechanism is proposed for this site-specific azidation

Piezotronic-Enhanced Photoelectrochemical Reactions in Ni(OH)₂‑Decorated ZnO Photoanodes

Controlling the interface electronic band structure in heterostructures is essential for developing highly efficient photoelectrochemical (PEC) photoanodes. Here, we presented an enhanced oxygen evolution reaction (OER) by introducing the piezotronics concept, i.e., piezoelectric polarization (<i>P</i>_pz)-induced band engineering. In a Ni­(OH)₂-decorated ZnO photoanode system, appreciably improved photocurrent density of sulfite (SO₃^2–) and hydroxyl (OH^–) oxidation reactions were obtained by physically deflecting the photoanode. Both theoretical and experimental results suggested that the performance enhancement was a result of the piezoelectric <i>P</i>_pz-endowed enlargement of the built-in electric field at the ZnO/Ni­(OH)₂ interface, which could drive an additional amount of photoexcited charges from ZnO toward the interface for OER. This strategy demonstrates a new route for improving the performance of inexpensive catalysts-based solar-to-fuel production

Coexpression of vWF and α-SMA in small vessels of the lungs from mice treated with either saline, or TGF-β1, or ET-1 or TGF-β1 plus ET-1.

<p>Confocal microscopy staining for vWF (red) and α-SMA (green) in the lungs from mice treated with saline (<b>A</b>), TGF-β1 (<b>B</b>), ET-1 (<b>C</b>), or TGF-β1 + ET-1 (<b>D</b>). DAPI was used for counterstaining of nuclei. Endothelial cells expressing vWF (red) are seen lining the large and small vessels of the lung. Activated myofibroblasts expressing α-SMA (green) are seen surrounding the vessels and in the interstitium. Cells co-staining for vWF and α-SMA (yellow; white arrows) in the small vessels represent cells in the process of endothelial-to-mesenchymal transition are observed in the TGF-β1 (<b>B</b>), ET-1 (<b>C</b>), or TGF-β1 + ET-1 (<b>D</b>)-treated animals. No double positive cells were observed in lungs from mice injected with saline (<b>A</b>). Magnification: 40X.</p

Effects of TGF-β1, or ET-1, or TGF-β1 plus ET-1 on the expression of fibrillar type I and type III collagens in murine lung microvascular endothelial cells.

<p>Murine lung endothelial cells were treated with either TGF-β1, or ET-1, or Bosentan, or with TGF-β1 plus ET-1, or with TGF-β1 plus ET-1 plus Bosentan for 72 h. (<b>A</b>). The upper panel shows a Western blot of culture supernatants probed with a Col1 primary antibody. The bottom panel shows a quantitative densitometry of bands corresponding to COL1 analyzed using NIH Image J software. (<b>B,C</b>). Expression levels of <i>Col1a1</i> (<b>B</b>), and <i>Col3a1</i> (<b>C</b>) as determined by semiquantitative RT-PCR. Values represent the mean (+/- standard deviation) expression levels of three replicates of three separate experiments. C(t) values were normalized with <i>Gapdh</i>. The saline control levels were arbitrarily set at 100% expression. Values for other samples are expressed relative to the saline control. Statistical significance was determined by Student’s two-tailed t test. **: p < 0.01; ***: p<0.001. T: TGF-β1; E: ET-1; B: Bosentan.</p

Effects of TGF-β1, or ET-1, or TGF-β1 plus ET-1 on the expression of mesenchymal cell-specific transcription factors in murine lung microvascular endothelial cells.

<p>Murine lung microvascular endothelial cells were treated with either TGF-β1, or ET-1, or bosentan, or with TGF-β1 plus ET-1, or with TGF-β1 plus ET-1 plus Bosentan for 72 h. Expression levels of <i>Snai1</i>(<b>A</b>), <i>Snai2</i> (<b>B</b>) and <i>Twist1</i> (<b>C</b>) were determined by semiquantitative RT-PCR. Values represent the mean (+/- standard deviation) expression levels of three replicates of three separate experiments. C(t) values were normalized with <i>Gapdh</i>. The saline control levels were arbitrarily set at 100% expression. Values for other samples are expressed relative to the saline control. Statistical significance was determined by Student’s two-tailed t test. **: p < 0.01; ***: p<0.001.</p