RESUMO
A covalent oxygen-rich C2N (CNO) network derived from metal-organic framework (HKUST-1) was innovatively synthesized by a rapid and green microwave irradiation method. This method can produce CNO multilayers efficiently, which paves a way for practical application of the nanosheets. Structural characterization and synthesis processes of CNO nanosheets were investigated to further understand the key role of HKUST-1. The as-prepared CNO has a layered feature, which theoretically favors to improve flame retardancy and mechanical performance of polymers. Desirable results were obtained as expected: the fire safety, antitensile, and impact resistance of polylactic acid (PLA) were prominently enhanced after adding CNO nanosheets, which can be attributed to the excellent dispersion and compatibility. PLA/CNO nanocomposite was self-distinguished at 2 wt % content of CNO, whereas the tensile strength was increased more than 36% compared with that of pure PLA, as well as the impact strength. This work broadens the application fields of CNO and endows it a possibility of actual application.
RESUMO
3-Diazoindolin-2-imines reacted with chiral 2-(phenylamino)ethanols under copper catalysis to furnish chiral spiro[indoline-3,2'-oxazolidin]-2-imines in good yields with excellent diastereoselectivity. The reaction undergoes a copper-catalyzed cascade process involving the formation of copper carbene, C-N coupling, and C-O coupling.
RESUMO
The rhodium-catalyzed reactions of 3-diazoindolin-2-imines with N,N-dialkylanilines, N-allyl-N-alkylanilines, and N-propargyl-N-alkylanilines and 3-diazoindolin-2-imines furnished 3-aryl-2-aminoindoles, 3-allyl-3-amino-2-iminoindolines, and tetrahydro-[1,4]diazepino[2,3-b]indoles, respectively. 3-Diazoindolin-2-imines acted as precursors of α-imino rhodium carbenes in these transformations.