A simple and convenient Ostwald ripening route to the morphology‐ and phase‐controlled preparation of hollow Sb2S3 microspheres is developed. The hollow spheres are clusters of smaller microspheres if orange amorphous Sb2S3 colloid is used as the precursor, whereas, if starting from the yellow precursor, the products are regular hollow spheres. By selecting appropriate experimental conditions for ripening, the phase of the hollow Sb2S3 microspheres can be controlled. Amorphous and orthorhombic hollow spheres are prepared by ripening the colloidal precursors at ambient temperature and in an autoclave, respectively. The closed shell of hollow Sb2S3 spheres can be easily eroded by hydrochloric acid to form an open structure. By the in situ reduction of adsorbed Ag+ on the surface and interior of the hollow spheres, Ag nanoparticles are introduced into them, to form functional metal–semiconductor composites, the weight content of which is controlled by regulating the concentration of the Ag+ source and the adsorption time. The composite structures composed of Ag nanoparticles and hollow Sb2S3 spheres exhibit a remarkably enhanced absorption covering the UV and visible regions of the electromagnetic spectrum. A study of the photocatalytic properties of the composite structures demonstrates that exposure to both UV and visible light enables them to induce the rapid decomposition of 2‐chlorophenol. The degradation rate increases with a larger weight content of Ag in the composite structure.
The
utilization of diphenyl sulfoxides as versatile electrophilic coupling
partners for the Suzuki–Miyaura reaction via C–S bond
cleavage was successfully developed under palladium-N-heterocyclic carbene catalysis. The reactions showed good functional
group compatibility, proceeded well under mild conditions, and provided
biaryls in yields of up to 96%. A wide range of useful functional
groups, such as fluoro, chloro, ether, hydroxyl, amide, cyano, keto,
trimethylsilyl (TMS), and ester were tolerated under the reaction
conditions; however, the use of phenylboronic anhydride and arylboronic
acid pinacol esters generally would lead low yields. Good regioselectivity
for the electron-poor phenyl group was achieved when unsymmetrical
diphenyl sulfoxides were used. The protocol is applicable at the gram
scale even with half the amount of catalyst. Density functional theory
calculations were performed to investigate the reaction mechanism,
indicating that the reaction occurred through oxidative addition,
transmetalation, and reductive elimination to provide the final coupling
product.
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