Synthesis,Reactions and Catalytic Activities of a Cationic Acrylonitrile-Rhodium(I) Complex

Reaction of RhCl (CO)(Ph₃P)₂(Ph₃P = triphenylphosphine) with AgClO₄ in acrylonitrile at 30°C produces a new cationic rhodium(I) complex, Rh(CH₂CHCN)(CO) (Ph₃P)₂]ClO₄ ($\text{1}$) and AgCl. The ¹H-NMR and IR spectra of $\text{1}$ suggest that acrylonitrile is coordinated to rhodium through the π-system of the vinyl group. The complex $\text{1}$ reacts with molecular hydrogen to give a propionitrile-rhodium(I) complex, Rh(CH₃ CH₂CN) (CO)(Ph₃P)₂ClO₄($\text{2}$) where the coordination of propionitrile through nitrogen is suggested by the ¹H-NMR and IR spectral data. The coordinated acrylonitrile in $\text{1}$ is readily replaced with triphenylphosphine and propionitrile to give Rh(CO)(Ph₃P)₃] ClO₄ and $\text{2}$, respectively. The complex $\text{1}$ is catalytically active for the hydrogenation and polymerization of acrylonitrile at 25°C under the atmospheric pressure of hydrogen.