Different copper oxide nanostructures: Synthesis, characterization, and application for C-N cross-coupling catalysis

Cupric oxide and cuprous oxide micro-/nanomaterials with well-controlled sizes and morphologies have been synthesized via different crystal growth techniques. Structural and morphological characterizations of these copper oxide micro-/nanomaterials were performed by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After that, these copper oxide micro-/nanomaterials were used as catalysts for a typical C-N cross-coupling reaction directly. The catalytic results showed that different copper oxide micro-/nanomaterials had different catalytic activities in C-N cross-coupling reaction. The particle size of cupric oxide and the oxidation state of copper played vital roles in the catalytic process. Cupric oxide with small particle size has the best catalytic activity, while cupric oxide with different morphologies has almost the same yields and cuprous oxide has very poor yields. Further, the possible catalytic mechanism for copper oxide nanomaterials catalyzed cross-coupling reaction was proposed. And the influence of particle size and oxidation state was carefully discussed. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim