Search

A CsF-promoted carboxylation of aryl(hetaryl) terminal alkynes with atmospheric CO2 in the presence of trimethylsilylacetylene was developed to give functionalized propiolic acid products at room temperature. A wide range of propiolic acids bearing functional groups was successfully obtained in good to excellent yields. Mechanistic studies demonstrate that in the carboxylation process the alkynylsilane intermediate was first in situ generated, which was then trapped by CO2, giving rise to the corresponding functionalized propiolic acids after acidification. The advantages of this approach include avoiding use of transition-metal catalysts, wide substrate scope together with excellent functional group tolerance, ambient conditions and a facile work-up procedure. [ABSTRACT FROM AUTHOR]

During the process of hydrogen generation via photocatalytic water splitting, solute ions may be adsorbed on the surface of the graphitic carbon nitride (g-C3N4) monolayer, modifying its electronic and optical performances, as well as its redox ability due to chemical bond relaxation. With the aid of first principles calculations, we investigated the properties of a g-C3N4 monolayer with a series of nonmetal (NM) ions adsorbed on its surface. The obtained results revealed that the adsorbed solute ions can form NM–N or NM–C bonds with the g-C3N4 monolayer and result in bond relaxation, altering the valence band maximum and conduction band minimum synchronously. The small coverage rate of Br, Cl and I ions enhances the redox ability of g-C3N4 synchronously, while the adsorption of the other solute ions enhances the oxidizability and weakens the reducibility. In addition, the adsorption of solute ions can alter the active sites by impacting the distribution of the highest occupied molecular orbital and the lowest unoccupied molecular orbital. Therefore, we can adjust the electronic, optical performances and redox ability of a g-C3N4 monolayer by selecting the suitable type and quantity of solute ions, e.g., the photocatalytic efficiency of g-C3N4 can be enhanced by H ions plus B, N, Si, O, P and As ions with high coverage rates plus halogen ions with low coverage rates while it is suppressed by C, S, Se and Te ions. [ABSTRACT FROM AUTHOR]

Novel multi-component self-assembled nano-vaccines containing both Pam3CSK4 and CpG were developed for the first time. These multi-component vaccines could effectively activate the macrophages in vitro and elicit strong antibody immune responses and anti-tumor immune responses in vivo. [ABSTRACT FROM AUTHOR]

The thermal stability and electronic structures of anatase TiO2 doped with early transition metals (TM) (group III-B = Sc, Y and La; group IV-B = Zr and Hf; group V-B = V, Nb and Ta) have been studied using first principles calculations. It was found that all doped systems are thermodynamically stable, and their band gaps were reduced by 1–1.3 eV compared to pure TiO2. Doping with transition metals affects the strength of the hybrid orbital of TM–O bonding, and the band gap increases approximately linearly with the MP value of TM–O bonding. [ABSTRACT FROM AUTHOR]

The thermal stability and electronic structures of anatase TiO2 doped with early transition metals (TM) (group III-B = Sc, Y and La; group IV-B = Zr and Hf; group V-B = V, Nb and Ta) have been studied using first principles calculations. It was found that all doped systems are thermodynamically stable, and their band gaps were reduced by 1-1.3 eV compared to pure TiO2. Doping with transition metals affects the strength of the hybrid orbital of TM-O bonding, and the band gap increases approximately linearly with the MP value of TM-O bonding.