Development of nano-structured metal oxides/heteroatom composites with controlled components and structure for photochemical oxidation still remains a great challenge. Here, a new and versatile strategy is reported for transformation of organonitrogen-encapsulated metal-organic frameworks (MOFs) into N-doped Fe 3 O 4 @C nanopolyhedron by chemical vapor deposition-induced super-assembly method. Strong confined interaction between organonitrogen guests (urea, thiourea, melamine, and dimethylimidazole) and Fe nodes of MOFs realizes reconstruction of crystal structure and introduction of N species. With the novel approach, the uniform dispersion of guests and perfect metallic/heteroatom interfacial is obtained. Compared with MOFs-derived Fe 2 O 3 /C, the heteroatom/defect-to-metal cluster charge transfer excitations lead N-doped Fe 3 O 4 @C to exhibit more superior activity for photocatalytic oxidation (turn-over frequencies as high as 3.72 h −1 ). It demonstrates that the introduction of abundant pyrrole-N and oxygen vacancies on carbon interface boosts the advance of photo-generated carrier transfer. The study offers a simple and promising strategy for the design of novel metal oxides/heteroatom composite with adjustable structure and functions.

Source of materialAcetic acid (0.4 g) was added to a solution of ethyl 3-amino-2-N-[(2¢-cyanobiphenyl-4-yl)methyl]aminobenzoate (2.0 g) in ethyl orthocarbonate (10 mL). The mixture was stirred at 353 K for one hour. The reaction mixture was concentrated, and the concentrate was dissolved in ethyl acetate. The solution was washed with an aqueous solution of sodium hydrogen carbonate and water. The solvent was evaporated to give crystals. Colorless single crystals of title compound suitable for diffraction analysis were obtained from an ethyl acetate solution after one week. Experimental detailsThe disordered ethyl group was split into two positions and the atomic positions were refined under using of restraints for CO and CC bond lengths. While the C atoms of the major part could be refined anisotropically, the respective atoms of the minor part had to be refined isotropically. Discussion