A Diolefin Diamide Rhodium(I) Complex and Its One-Electron Oxidation Resulting in a Two-Center, Three-Electron Rh-N Bond

A tetracoordinated diolefin diamide rhodium(I) complex 6 with the two amido and olefin groups in mutual trans-position and a butterfly structure has been prepared. This anionic complex undergoes a reversible one-electron oxidation at a remarkably negative potential (E-1/2 = -1.22 V vs. Fc/Fc(+)) to give a stable, paramagnetic, tetracoordinated, planar Rh-I complex 7. This complex was fully characterized, and all data indicate that this species is best described with an unprecedented two-center, three-electron Rh-N bond. DFT computations were performed to further elucidate the electronic structure, and the results fully agree with the two-center, three-electron Rh-N bond description.