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A novel water-assisted chemical vapor deposition (CVD) method for the efficient synthesis of boron nitride (BN) nanotubes is demonstrated. The replacement of metal oxide by water vapor could continuously generate intermediate boron oxide vapor and enhance the production of BN nanotubes. The nanotubes synthesized when an appropriate amount of water vapor was introduced had an average diameter of about 80 nm and lengths of several hundred μm. The diameter and yield of nanotubes could be controlled by tuning the amount of water vapor. This simple water-assisted CVD approach paves a new path to the fabrication of BN nanotubes in large quantities.

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Metal nanoclusters (MNCs), including Ag NCs, Cu NCs, and Au NCs, can be used as fluorescent probes for nucleic acid testing. Identification of DNA fragments and trace detection of miRNA (LOD as low as aM) can be achieved.

Density functional calculations have been performed to comparatively investigate two possible pathways of Au(I)-catalyzed Conia-ene reaction of β-ketoesters with alkynes. Our studies find that, under the assistance of trifluoromethanesulfonate (TfO), the β-ketoester is the most likely to undergo Model II to isomerize into its enol form, in which TfO plays a proton transfer role through a 6-membered ring transition state. The coordination of the Au(I) catalyst to the alkynes triple bond can enhance the eletrophilic capability and reaction activity of the alkynes moiety, which triggers the nucleophilic addition of the enol moiety on the alkynes moiety to give a vinyl-Au intermediate. This cycloisomerizaion step is exothermal by 21.3 kJ/mol with an energy barrier of 56.0 kJ/mol. In the whole catalytic process, the protonation of vinyl-Au is almost spontaneous, and the formation of enol is a rate-limiting step. The generation of enol and the activation of Au(I) catalyst on the alkynes are the key reasons why the Conia-ene reaction can occur in mild condition. These calculations support that Au(I)-catalyzed Conia-ene reactions of β-ketoesters with alkynes go through the pathway 2 proposed by Toste.