Synthesis and reactivity of new benzophenone imine derivatives containing the Ru(CO)(PiPr3)2 unit

Article abstract of DOI:10.1016/S0022-328X(96)06466-2

The five-coordinate bis(alkynyl) complex Ru(C₂Ph)₂(CO)CPⁱPr₃)₂ (1) reacts with benzophenone imine to give Ru(C₂Ph){NH=C(Ph)C₆H₄}(CO)(PⁱPr₃)₂ (2), which affords Ru(FBF₃){NH=C(Ph)C₆H₄}(CO)(PⁱPr₃)₂ (3) and phenylacetylene by reaction with HBF₄ - OEt₂. The addition of Lewis bases such as CO, MeCN and P(OMe)₃ to dichloromethane solutions of 3 leads to [Ru{NH=C(Ph)C₆H₄}(CO)L(PⁱPr₃)₂]BF₄ (L = CO (4), MeCN (5)) and [Ru{NH=C(Ph)C₆H₄}(CO){P(OMe)₃}₂(PⁱPr₃)]BF₄ (6). Complex 3 also reacts with MeLi to give Ru(Me){NH=C(Ph)C₆H₄}(CO)(PⁱPr₃)₂ (7), which affords RuH{NH=C(Ph)C₆H₄}(CO)(PⁱPr₃)₂ (8) by treatment with methanol. In this complex, the hydrido ligand is disposed trans to the orthometallated phenyl ring. The reaction of the five-coordinate hydrido-chloro complex RuHCl(CO)(PⁱPr₃)₂ (9) with LiN=CPh₂ leads to the azavinylidene derivative RuH(=N=CPh₂)(CO)(PⁱPr₃)₂ (10). Complex 10 is unstable in methanol and evolves to a mixture of 8 and its isomer RuH{NH=C(Ph)C₆H₄}(CO)(PⁱPr₃)₂ (11), containing the hydrido ligand cis disposed to the orthometallated phenyl ring. This isomer can be obtained as an analytically pure solid in the presence of triisopropylphosphine. The reaction of 9 with benzophenone imine leads to RuHCl(CO)(NH=CPh₂)(PⁱPr₃)₂ (12), which reacts with AgBF^-₄ to give [RuH(CO)(NH=CPh₂)(PⁱPr₃)₂]BF₄ (13). The reaction of 13 with carbon monoxide affords [RuH(CO)₂(NH=CPh₂)(PⁱPr₃)₂]BF₄ (14).