Mechanism of Rhodium-Catalyzed Formyl Activation: A Computational Study

Metal-catalyzed transfer hydroformylation is an important way of cleaving C–C bonds and constructing new double bonds. The newly reported density functional theory (DFT) method, M11-L, has been used to clarify the mechanism of the rhodium-catalyzed transfer hydroformylation reported by Dong et al. DFT calculations depict a deformylation and formylation reaction pathway. The deformylation step involves an oxidative addition to the formyl C–H bond, deprotonation with a counterion, decarbonylation, and β-hydride elimination. After olefin exchange, the formylation step takes place via olefin insertion into the Rh–H bond, carbonyl insertion, and a final protonation with the conjugate acid of the counterion. Theoretical calculations indicate that the alkalinity of the counterion is important for this reaction because both deprotonation and protonation occur during the catalytic cycle. A theoretical study into the formyl acceptor shows that the driving force of the reaction is correlated with the stability of the unsaturated bond in the acceptor. Our computational results suggest that alkynes or ring-strained olefins could be used as formyl acceptors in this reaction

Synthesis of Benzidine Derivatives via FeCl₃·6H₂O‑Promoted Oxidative Coupling of Anilines

Under open-flask conditions in the presence of commercially available FeCl₃·6H₂O, N,N-disubstituted anilines can be converted into diversely functionalized benzidines with yields of up to 99%. Oxidative coupling was extended to N-monosubstituted anilines, and the method was applied to the efficient preparation of 6,6′-biquinoline. Mechanistic investigations have also been performed to explain the observed reactivities

Synthesis of Benzidine Derivatives via FeCl₃·6H₂O‑Promoted Oxidative Coupling of Anilines

Under open-flask conditions in the presence of commercially available FeCl₃·6H₂O, N,N-disubstituted anilines can be converted into diversely functionalized benzidines with yields of up to 99%. Oxidative coupling was extended to N-monosubstituted anilines, and the method was applied to the efficient preparation of 6,6′-biquinoline. Mechanistic investigations have also been performed to explain the observed reactivities

Hydrothermal Synthesis of a New Kind of N‑Doped Graphene Gel-like Hybrid As an Enhanced ORR Electrocatalyst

In this work, g-C₃N₄@GO gel-like hybrid is obtained by assembling intentionally exfoliated g-C₃N₄ sheets on graphene oxide (GO) sheets under a hydrothermal condition. A specific N-doping process is first designed by heating the g-C₃N₄@GO interlaced hybrid in vacuum to form nitrogen-doped graphene nanosheets (NGS) with high level of pyridinic-N (56.0%) and edge-rich defect structure. The prepared NGS exhibited a great electrocatalysis for oxygen reduction reaction (ORR) in terms of the activity, durability, methanol tolerance, and the reaction kinetics. And the excellent electrocatalytic performance stems from the effective N-doped sites that the nitrogen atom is successfully doped at the defective edges of graphene, and the annealing temperature can play significant role of the doping pattern and location of N. The research provides a new insight into the enhancement of electrocatalysis for ORR based on nonmetal carbons by using the novel N-doping method

Template Synthesis of an Ultrathin β‑Graphdiyne-Like Film Using the Eglinton Coupling Reaction

β-Graphdiyne (β-GDY) is a two-dimensional carbon material with zero band gap and highly intrinsic carrier mobility and a promising material with potential applications in electronic devices. However, the synthesis of continuous single or ultrathin β-GDY has not been realized yet. Here, we proposed an approach for ultrathin β-GDY-like film synthesis using graphene as a template because of the strong π–π interaction between β-GDY and graphene. The as-synthesized film presents smooth and continuous morphology and has good crystallinity. Electrical measurement reveals that the film presented a conductivity of 1.30 × 10^–2 S·m^–1 by fabricating electronic devices on β-GDY grown on a dielectric hexagonal boron nitride template

Inhibition of ICAM-1 <i>N</i>-glycan elongation or processing by ATRA suppresses cell adhesion.

<p>A, Schematic presentation of the protocol used to determine the effect of ATRA on cell adhesion. Briefly, SW480 cells were transfected with the GnT-III specific siRNA, treated with ATRA and then co-incubated with the HUVEC monolayer. The cell adhesion was assessed by counting the cells attached to the HUVEC monolayer. B, The cells attached to the HUVEC monolayer were observed under a confocal microscope. C, The adherent cells were analyzed by cell counting. D, SW480 cells were pretreated with 10 µM U0126 and then with 25 µM ATRA. The cells attached to the HUVEC monolayer were observed under a confocal microscope. E, The adherent cells were analyzed by cell counting.</p

ATRA-induced GnT-III expression is involved in the modulation of ICAM-1 <i>N</i>-glycan composition.

<p>A, SW480 cells were treated with 25 µM ATRA for 0, 18 and 36 h. The expression of GnT-III and GnT-V at the mRNA levels was detected by real-time RT-PCR (n = 3). B and C, SW480 cells that were transiently transfected with 50 nM of the siRNA specifically targeting GnT-III were treated with 25 µM ATRA. The efficiency of transfection was analyzed by real-time RT-PCR (n = 3, B) and the expression of ICAM-1 by Western blot (C). D, SW480 cells were treated with 25 µM ATRA. Then immunoprecipitation by the antibody against ICAM-1 (1.5 µg per 500 µg of total protein) was performed. The immunoprecipitated products were subjected to 10% SDS-PAGE, transferred to a nitrocellulose membrane and consecutively incubated with biotinylated L-PHA or E-PHA lectin, streptavidin-labled rabbit IgG and HRP-labeled goat anti-rabbit IgG. Bound HRP on the membranes was detected by ECL. E, SW480 cells were pretreated with 0.7 nM stauroporine, 10 µM H-89, 10 µM SB203580, 10 µM U0126, 50 µM PD98059, 20 µM SP600125 or 50 µM LY294002 for 2 h and then exposed to 25 µM ATRA for 36 h. The expression of ICAM-1 and phosphorylation of ERK were analyzed by Western blot. F, SW480 cells were pretreated with 10 µM U0126 and then with 25 µM ATRA. The expression of GnT-III at the mRNA level was analyzed by real-time RT-PCR (n = 3).</p

Schematic presentation of the mechanisms by which ATRA modulates the structure of <i>N</i>-glycans linked to ICAM-1.

<p>Schematic presentation of the mechanisms by which ATRA modulates the structure of <i>N</i>-glycans linked to ICAM-1.</p

The primers used.

<p>The primers used.</p

Additional file 1: Figure S1. of The Oxygen Reduction Electrocatalytic Activity of Cobalt and Nitrogen Co-doped Carbon Nanocatalyst Synthesized by a Flat Template

(a) CV and (b) LSV curves of Co-NC catalysts in O2-saturated 0.1 mol l–1 KOH solution. Figure S2. (a) CV and (b) LSV curves of Co-NCcatalysts in O2-saturated 0.1 mol l–1 HClO4 solution. (DOCX 221 kb