Insertion Reactions of <i>trans</i>-Mo(dmpe)₂(H)(NO) with Imines

The insertion chemistry of the hydride complex trans-Mo(dmpe)2(H)(NO) (1) (dmpe = bis(dimethylphosphino)ethane) with imines has been investigated. It was found that disubstituted aromatic imines RCHNR‘ (R, R‘ = Ar) insert into the Mo−H bond of 1, while a series of various mono- and other disubstituted imines do not react. The insertion products trans-Mo(dmpe)2(NO)[NR‘(CH2R)] (R = R‘ = Ph (2); R = Cp2Fe, R‘ = Ph (3); R = Ph, R‘ = Cp2Fe (4); R = 1-naphthyl, R‘ = Ph (5)) have been isolated and fully characterized by elemental analysis, IR and NMR spectroscopy, and mass spectrometry. The imine PhCHNC10H7 (C10H7 = 1-naphthyl) reacted with 1 establishing an equilibrium to produce the nonisolable complex trans-Mo(dmpe)2(NO)[NC10H7(CH2Ph)] (6). The equilibrium constant for this reaction has been derived from VT-NMR measurements, and the ΔH and ΔS values of this reaction were calculated to be −48.8 ± 0.4 kJ·mol-1 and −33 ± 1 J·K-1·mol-1 reflecting a mild exothermic process and its associative nature. Single-crystal X-ray diffraction analyses were carried out on 2−5.