Iminophosphanes: Synthesis, Rhodium Complexes, and Ruthenium(II)-Catalyzed Hydration of Nitriles

Highly
stable iminophosphanes, obtained from alkylating nitriles
and reaction of the resulting nitrilium ions with secondary phosphanes,
were explored as tunable P-monodentate and 1,3-P,N bidentate ligands
in rhodium complexes. X-ray crystal structures are reported for both
κ1 and κ2 complexes with the counterion
in one of them being an unusual anionic coordination polymer of silver
triflate. The iminophosphane-based ruthenium­(II)-catalyzed hydration
of benzonitrile in 1,2-dimethoxyethane (180 °C, 3 h) and water
(100 °C, 24 h) and under solvent free conditions (180 °C,
3 h) results in all cases in the selective formation of benzamide
with yields of up to 96%, thereby outperforming by far the reactions
in which the common 2-pyridyldiphenylphosphane is used as the 1,3-P,N
ligand.