An extension of nickel-catalyzed reductive coupling between tertiary alkyl halides with allylic carbonates

The nickel catalyzed reductive coupling of allylic carbonates with chloro-cyclotryptamine analogs to construct sterically congested all C(sp³) quaternary centers has been achieved with emphasis on the substrate scope. And the using of dienyl methyleneyl carbonates coupling with a variety of tertiary alkyl halides furnished the dienylated products improved the reaction's applicability.     

Influence of Functional Groups and Modi cation Sites of Metal-Organic Frameworks on CO2/CH4 Separation: A Monte Carlo Simulation Study

In order to explore the in uence of modification sites of functional groups on landfill gas (CO₂/CH₄) separation performance of metal-organic frameworks (MOFs), six types of organic linkers and three types of functional groups (i.e. -F, -NH₂, -CH₃) were used to construct 36 MOFs of pcu topology based on copper paddlewheel. Grand canonical Monte Carlo simulations were performed in this work to evaluate the separation performance of MOFs at low (vacuum swing adsorption) and high (pressure swing adsorption) pressures, respectively. Simulation results demonstrated that CO₂ working capacity of the unfunctionalized MOFs generally exhibits pore-size dependence at 1 bar, which increases with the decrease in pore sizes. It was also found that -NH₂ functionalized MOFs exhibit the highest CO₂ uptake due to the enhanced Coulombic interactions between the polar -NH₂ groups and the quadrupole moment of CO₂ molecules, which is followed by -CH₃ and -F functionalized ones. Moreover, positioning the functional groups -NH₂ and -CH₃ at sites far from the metal node (site b) exhibits more significant enhancement on CO₂/CH₄ separation performance compared to that adjacent to the metal node (site a).     

Growth of NaBi(WO4)2 crystal by modified-Bridgman method

NaBi(WO₄)₂ (NBW) crystals have been grown for the first time by modified-Bridgman method. Influences of some factors on the crystal growth process are discussed. X-ray powder diffraction experiments show that the unit cell parameters of NBW crystal are a=b=0.5284 nm, c=1.1517 nm, and V=0.3215 nm³. The differential thermal analysis shows that the NBW crystal melts at 923°C.     

Aggregation and columnar assembly of crescent oligoamides

The aggregation and assembly of crescent oligoamides with two to six benzene residues are investigated. In chloroform, the pentamer and hexamer are found to associate into large aggregates. In the solid state, all oligomers examined associate into columnar assemblies via stacking interactions, as shown by X-ray diffraction data from single crystals and powder samples. The columnar assemblies of the pentamer and hexamer should contain hydrophilic channels defined by the constituent oligomers.     

Synthesis of (2-oxoindolin-3-ylidene)methyl acetates involving a C-H functionalization process

A novel palladium-catalyzed oxidative C-H functionalization protocol for the synthesis of (2-oxoindolin-3-ylidene)methyl acetates has been developed. In the presence of Pd(OAc)2 and PhI(OAc)2, a variety of N-arylpropiolamides underwent the C-H functionalization reaction with acids to afford the corresponding (E)-(2-oxoindolin-3-ylidene)methyl acetates selectively in moderate to excellent yields.     

Drop properties and approximative compactness in Orlicz-Bochner function spaces

The representation of dual spaces of EM(μ,X), owing to its extensive application, is given in this paper. Using the representation, we get the sufficient and necessary conditions of LM(μ,X) possessing drop property, and extend the result of Hudzik and Wang [H. Hudzik, B. Wang, Approximative compactness in Orlicz spaces, J. Approx. Theory 95 (1998) 82-89]. Simultaneously, under some conditions, the weak^∗ drop property in LM(μ,X^∗) and LM^∗(μ,X) is discussed.     

An organic p-type dopant with high thermal stability for an organic semiconductor

To overcome the thermal instability of a p-doped organic hole transporting layer using the state-of-the-art p-type dopant, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, a potent electron accepter, 3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane, has been found to possess superior thermal stability and proved to be an excellent p-type dopant.     

Bifunctional sensor of nitric oxide and oxygen based on hematite nanotubes embedded in chitosan matrix

A novel hybrid bifunctional sensing platform for simultaneous determination of NO and O₂ has been developed, whereby hematite nanotubes are immobilized into the chitosan matrix onto a gold electrode (labeled as HeNTs-Chi/Au). The HeNTs distributed in porous-structured chitosan matrix not only offer abundant active sites for bifunctional sensing of NO and O₂, but also facilitate oxidation of NO and reduction of O₂ dramatically. Straight calibration curves are achieved in analyte concentration ranges of 5.0 × 10⁻⁸ to 1.25 × 10⁻⁶ mol L⁻¹ for NO and 2.5 × 10⁻⁷ to 6.0 × 10⁻⁶ mol L⁻¹ for O₂. Also, the detection limits are low of 8.0 × 10⁻⁹ mol L⁻¹ for NO and 5.0 × 10⁻⁸ mol L⁻¹ for O₂. Such an efficient bifunctional sensor for NO and O₂ offers great potential in quantitation of NO levels in biological and medical systems, since NO level is highly regulated by various reactive oxygen species.