Cu2O polyhedra for aryl alkyne homocoupling reactions

Abstract

Cu₂O cubes, octahedra and rhombic dodecahedra were employed to catalyze homocoupling reactions of aryl alkynes. The X-ray diffraction (XRD) patterns of the Cu₂O crystals show slight peak shifts for the different particle shapes, which may be a manifestation of bond-level deviations within the thin surface layer as predicted by density functional theory (DFT) calculations. Infrared spectral characterization indicates acetylenic carbons binding to copper atoms of the Cu₂O crystals, and this may be the intermediate state in the coupling reaction. Cu₂O rhombic dodecahedra exhibit the best catalytic performance toward homocoupling of phenylacetylene, and they also catalyze homocoupling of a variety of substituted aryl alkynes, showing the advantage of Cu₂O facet control to driving important organic coupling reactions.