Copper(I)-Anilide Complex [Na(phen)3][Cu(NPh2)2]: An Intermediate in the Copper-Catalyzed N-Arylation of N-Phenylaniline

Complex [Na(phen)(3)][Cu(NPh2)(2)] (2), containing a linear bis(N-phenylanilide) copper(I) anion and a distorted octahedral tris(1,10-phenanthroline) sodium counter cation, has been isolated from the catalytic C-N cross-coupling reaction with the CuI/phen/tBuONa (phen=1,10-phenanthroline) catalytic system. Complex 2 can react with 4-iodotoluene to produce 4-methyl-N,N-diphenylaniline 3a) with 70.6% yield. In addition, 2 can work as an effective catalyst for C-N coupling under the same reaction conditions, thus indicating that 2 is the intermediate of the catalytic system. Both [Cu(NPh2)(2)](-) and [Cu(NPh2)I](-) have been observed by in situ electron ionization mass spectrometry (ESI-MS) under catalytic reaction conditions, thus confirming that they are intermediates in the reaction. A catalytic cycle has been proposed based on these observations. The molecular structure of 2 has been determined by single-crystal X-ray diffraction analysis.