Falkkamp1009

A palladium-catalyzed cross-coupling reaction of 2-alkylphenyl bromides with biphenylene has been developed. The reactions formed eight-membered carbocycles through C(sp3)-H activation and the formation of two C-C bonds, and the chiral products were obtained with excellent diastereoselectivity. The reaction provides a new strategy for the construction of eight-membered carbocycles, and the products represent a novel type of chiral scaffold.In the presence of aldehyde, a facile method was developed to obtain N-sulfonyl amidines under metal- and oxidant-free conditions by the decarboxylative of proline. This transformation features a double C-N bond formation and allows for the green synthesis of the N-sulfonyl amidines on the basis of mild conditions.A nitrogen-centered radical-mediated strategy for preparing 1,2-trans-2-amino-2-deoxyglycosides in one step was established. The cascade amidoglycosylation was initiated by a benzenesulfonimide radical generated from NFSI under the catalytic reduction of TEMPO. The benzenesulfonimide radical was electrophilically added to the glycals, and then the resulting glycosidic radical was converted to oxocarbenium upon oxidation by TEMPO+, which enabled the following anomeric specific glycosylation.Determining the trajectory of ionic transport and diffusion within single electroactive nanomaterials is critical for understanding the charging kinetics and capacity fading associated with ion batteries, with implications for rational design of excellent-performance electrode materials. While the horizontal pathway of mass transport has been feasibly investigated by optical superlocalization methods and electron microscopes, determination on the vertical trajectory has proven a more challenging task. Herein, we developed dual-angle total internal reflection microscopy by simultaneously introducing different angle-dependent illumination depths to trace the optical centroid shifts of nano-objects in the vertical dimension. click here We first demonstrated the proof of concept by resolving the vertical moving trails of a nanosphere doing Brownian motion and subsequently explored the picture of mass transport in the interior of single Prussian blue (PB) particles during electrochemical cycling. The results indicated that the vertical centroids of single PB particles remained unchanged when ions were inserted or extracted, suggesting an outside-in ionic transport pathway instead of bottom-up trajectory that one would intuitively expect.Porous polyimide (PI) materials are one of important bearing retainer materials in space applications due to the storage and continuous supply of a lubricant through the porous structure. Understanding the lubricant recycling process in porous polyimide retainers is of vital importance to improve lubricant supply performance of bearing. In this work, through molecular dynamic simulations, coarse-grained models are built to study lubricant recycling processes on porous and solid surfaces. A spontaneous imbibition behavior is observed when the lubricant is present on the porous surface. The dynamic change in the contact angle in this process and the deviation of the effective radius from the volumetric radius because of the molecular structure of polyimide causes the classical Lucas-Washburn (L-W) equation fail to describe the process. By fitting dynamic contact angle and effective radius, a modified L-W equation is developed, which well predicts the process of imbibition. Furthermore, it is found that the lubricants between the porous polyimide surface and the solid surface are recycled by extrusion, and spontaneous imbibition does not occur. In this case, the accumulation of lubricant pressure and weak interfacial interaction between the lubricant and the solid surface are also the main factors that promote lubricant recycling.The angiotensin-converting enzyme (ACE) inhibitory peptide LVLPGE provides outstanding antihypertensive effects in vivo, with a maximum systolic blood pressure (SBP) drop of 39 mmHg at a dose of 10 mg/kg. We evaluated the gastrointestinal digestion, transport, and in vivo antihypertensive effects of LVLPGE at different doses. LVLPGE was resistant to gastrointestinal enzymes with a stability of 97.8% and a permeability Papp of (5.09 ± 0.94) × 10-7 cm/s. LVLPGE was mainly transported through the Caco-2 cell monolayer by the peptide transporter PepT 1 and passive-mediated transport. LVLPGE at doses of 30 and 50 mg/kg had a positive antihypertensive effect in vivo; 30 mg/kg had a more significant effect than 50 mg/kg. After oral administration, the pharmacokinetics of LVLPGE showed that the Cmax was 4.65 ng/mL at 2 min. The blood pressure-lowering effect increased as the concentration of LVLPGE increased in the plasma of spontaneous hypertensive rats (SHRs).A benzene-free synthesis of multisubstituted catechol via an oxidative dearomatic reorganization is reported. This reaction tolerated a wide spectrum of functionalities, which could be applied in the synthesis of an electron-deficient arene-conjugated catechol that is difficult to access via biomimetic oxidative coupling. In addition, a diversification-oriented transformation that leveraged the versatile catechol afforded a series of functionality-rich products.The Rh(III)-catalyzed ortho-alkynylation of benzaldehydes is enabled by the transient formation of an imine as a directing group. A broad scope of substrates was obtained under mild reaction conditions, granting access to mono- and dialkynylated products. The functionalization of readily available building blocks allowed the development of modular syntheses of dibenzopentalenes, isoquinolines, indoles, and indolines.Cytochrome c oxidase (CcO) in its as-isolated form is known to exist in a slow and fast form, which differ drastically in their ability to bind oxygen and other ligands. While preparation methods have been established that yield either the fast or the slow form of the protein, the underlying structural differences have not been identified yet. Here, we have performed surface enhanced resonance Raman (SERR) spectroscopy of CcO immobilized on electrodes in both forms. SERR spectra obtained in resonance with the heme a3 metal-to-ligand charge transfer (MLCT) transition at 650 nm displayed a sharp vibrational band at 748 or 750 cm-1 when the protein was in its slow or fast form, respectively. DFT calculations identified the band as a mode of the His-419 ligand that is sensitive to the oxygen ligand and the protonation state of Tyr-288 within the binuclear complex. Potential-dependent SERR spectroscopy showed a redox-induced change of this band around 525 mV versus Ag/AgCl exclusively for the fast form, which coincides with the redox potential of the Tyr-O/Tyr-O- transition.