No abstract

With the continuous development of N-heterocyclic carbene (NHC) chemistry during the past decade, NHC metal complexes have gained wide applications in the research field of organometallic catalysis. The recycling and reuse of NHC metal complexes, which have undergone continuous expansion and diversification, can enhance their catalytic performance, extend their range of application, and afford new routes to green chemistry. Taking NHC metal complex catalysts as the main topic, this review intends to present a comprehensive study of recycling strategies of organometallic catalysts. By an elaborative summarization and classification of recycling strategies, a clear picture of all available of recycling strategies for organometallic catalysts is presented and the advantages and disadvantages of various recycling strategies for specific reactions are discussed in detail. This review is written with the hope of serving as a modest spur to induce other scientists' further contributions in the fields of catalyst recycling and sustainable catalysis.

Theoretical calculations have predicted that the band gap of boron carbonitride (BCN) nanotubes can be tailored over a wide range by chemical composition rather than by geometrical structure. The following attempts toward the fabrication of BCN nanotube devices should be of great importance both to further understand their electronic properties and to develop their prospective applications for nanoscale electronic and photonic devices. Here, the direct synthesis of massive BCN/C nanotube junctions has been realized via a bias-assisted hot-filament chemical vapor deposition method. The electrical transport measurements of individual nanotube junctions were performed on a conductive atomic force microscopy. It is found that the BCN/C nanotube junction shows a typical rectifying diode behavior.