Clemmensenclemons9004

Soluble surfactants form thick adsorption layers at the air-liquid interface, but classical adsorption models fail to account for it as they treat the adsorption layer as a mathematical plane (of zero thickness). This simplification has produced several inconsistencies between theoretical predictions and experimental results, especially for the surface potential. Here, we develop a new adsorption model for ionic surfactants at the air-water interface that incorporates the effect of the adsorption layer thickness using a modified Poisson-Boltzmann equation that integrates information from molecular dynamics simulation. We show that the surface potential depends sensitively on both the thickness of the adsorption layer and the interfacial depth at which the surface potential is probed. This model, therefore, provides a much more accurate picture of the surface potential than classical models.Sulfonylated N-unsubstituted enamines were synthesized through a chain of chemical and electrochemical transformations via sulfonylation of vinyl azides. The disclosing of the N-unsubstituted enamines synthesis was based on a unique property of the azido group, which is its ability to eliminate the N2 molecule. Furthermore, a formal paradox is observed a double bond reacts and a double bond is retained. Electrosynthesis proceeded in an undivided cell equipped with a graphite anode and a stainless steel cathode; NH4I was used as a supporting electrolyte.We report here the first example of a sulfo-click conjugation reaction to be applied to modified nucleosides. The reaction, which proceeds rapidly (k ∼ 2.0 × 10-1 M-1 s-1 at 25 °C) under aqueous biocompatible conditions in the ribo- and deoxyribonucleoside series, affords the corresponding conjugated products in excellent yields. Furthermore, we demonstrate the orthogonality of the reaction with the copper-catalyzed azide-alkyne click reaction (CuAAC) by performing a one-pot dual labeling of a nucleoside carrying two orthogonal azido groups.To get an idea about the most probable microporous supramolecular environment in the gel state, gelator molecule 1 has been crystallized from its gelling solvent (dimethylformamide). Crystal structure analysis of 1 shows a strong π···π stacking interaction between the electron-deficient pentafluorophenyl ring and electron-rich naphthyl ring. The gelling solvent situated in the "molecular pocket" stitches the gelators through weak H-bonding interactions to facilitate the formation of an organogel. Scanning electron microscopy analysis exhibits a ribbonlike fibrous morphology that resembles the supramolecular arrangement of 1 in its crystalline state, as evidenced by powder X-ray diffraction. In the presence of external stimuli (tetrabutylammonium fluoride), the organogel of 1 disassembles into sol. This sol-gel transformation phenomenon has been explained on the basis of X-ray single-crystal analysis. Single crystals obtained from the sol state show that naphthylic -OH of 1 gets deprotonated, resulting in C-C bond rotation that plays a major role in the sol-gel transformation. Gelator 1 exhibits weak green fluorescence in the gel state, whereas it shows highly intense yellow fluorescence in the sol state. Furthermore, a reversible sol-gel transformation associated with changes in the spectroscopic properties has been observed in the presence of acids and fluoride ions, respectively.Here, we report O-methyl S-aryl thiocarbonates as a versatile esterification reagent for palladium-catalyzed methoxycarbonylation of arylboronic acid in the presence of copper(I) thiophene-2-carboxylate (CuTC). The reaction condition is mild, and a variety of substituents including sensitive -Cl, -Br, and free -NH2 could be tolerated. Further applications in the late-stage esterification of some pharmaceutical drugs demonstrate the broad utility of this method.We present a theoretical study of the time-dependent laser alignment of molecules taking into account the hyperfine coupling due to nuclear-quadrupole interactions. The coupling of nuclear spins to the overall angular momentum of molecules significantly influences their rotational dynamics. Here, we systematically analyze the impact of the nuclear-quadrupole coupling on the rotational dynamics of the linear and the asymmetric-top diiodobenzene molecule induced by external laser fields. We explore different regimes of pulse shapes and laser-pulse intensities and detail under which conditions the quadrupole coupling cannot be neglected in the description of the laser alignment of molecules.An anionic oxy-Cope/transannular Michael addition cascade converts a spirocyclic architecture-readily available by Diels-Alder cycloaddition-into the hydrophenalene carbon skeleton of the pseudopterosin aglycones. Oxidation of the resulting cyclohexenone ring to the phenol that is characteristic of the targets completes a short formal synthesis.An electrochemical method for the C(sp2)-H thioetherification of quinoxalin-2(1H)-ones with primary, secondary, and tertiary thiols has been reported. Various quinoxalin-2(1H)-ones underwent this thioetherification smoothly under metal- and chemical oxidant-free conditions, affording 3-alkylthiol-substituted quinoxalin-2(1H)-ones in moderate to good yields.It is vital and promising for portable and disposable biosensing devices to achieve on-site detection and analysis of cancer cells. Although traditional labeling techniques provide an accurate quantitative measurement, the complicated cell staining and high-cost measurements limit their further development. Here, we demonstrate a nonimmune biosensing technology. selleck kinase inhibitor The plasmonic biosensors, which are based on anisotropic resonant split ring resonators in the terahertz range, successfully realize the antibody-free recognition of cancer cells. The dependences of Δf and the fitted phase slope on the cancer cell concentration at different polarizations give new perspective in hexagonal radar maps. The results indicate that the lung cancer cell A549 and liver cancer cell HepG2 can be distinguished and determined simply based on the enclosed shapes in the radar maps without any antibody introduction. The minimum concentration of identification reduces to as low as 1 × 104 cells/mL and such identification can be kept valid in a wide range of cell concentration, ranging from 104 to 105.