Synthesis of CuBr tetrahedra for phenylacetylene homocoupling and reductive amination reactions

CuBr tetrahedral crystals with average sizes of 116, 213, and 328 nm have been synthesized at 15 °C. Unit cell constant lengthens slightly with increasing particle sizes, which is linked to the small band gap red-shifts for larger crystals. The CuBr tetrahedra outperformed commercial CuBr powder in phenylacetylene homocoupling and reductive amination reactions between benzaldehyde and aniline. In addition to their large size difference, commercial CuBr powder and CuBr tetrahedra also show a considerable 0.8 % cell constant difference, which should affect catalytic activity. The 116 nm tetrahedra remained stable after multiple cycles of reductive amination reaction, and can catalyze reductive amination using different substituted aryl aldehydes and arylamines. Thus, the nanoscale tetrahedra are a superior source of CuBr for broad catalytic applications.