Synthesis and reactivity of new benzophenone imine derivatives containing the Ru(CO)((PPr3)-Pr-i)(2) unit

The five-coordinate bis(alkynyl) complex Ru(C(2)Ph)(2)(CO)(CPPr3)-Pr-i)(2) (1) reacts with benzophenone imine to give Ru(C(2)Ph)({NH=C(Ph)C6H4}(CO)((PPr3)-Pr-i)(2) (2), which affords Ru(FBF3)(NH=C(Ph)C6H4)(CO)((PPr3)-Pr-i)(2) (3) and phenylacetylene by reaction with HBF4 . OEt(2). 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((PPr3)-Pr-i)(2)]BF4(L = CO (4), MeCN (5)) and [Ru{NH=C(Ph)C6H4}(CO){P(OMe)(3)}(2)((PPr3)-Pr-i)]BF4 (6). Complex 3 also reacts with MeLi to give Ru(Me){NH=C(Ph)C6H4}(CO)((PPr3)-Pr-i)(2) (7), which affords RuH{NH=C(Ph)C6H4}(CO)((PPr3)-Pr-i)(2) (8) by treatment with methanol. In this complex, the hydride ligand is disposed trans to the orthometallated phenyl ring. The reaction of the five-coordinate hydrido-chloro complex RuHCl(CO)((PPr3)-Pr-i)(2) (9) with LiN=CPh(2) leads to the azavinylidene derivative RuH(=N=CPh(2))(CO)((PPr3)-Pr-i)(2) (10). Complex 10 is unstable in methanol and evolves to a mixture of 8 and its isomer RuH{NH=C(Ph)C6H4}(CO)((PPr3)-Pr-i)(2) (11), containing the hydride 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=CPh(2))((PPr3)-Pr-i)(2) (12), which reacts with AgBF4- to give [RuH(CO)(NH=CPh(2))((PPr3)-Pr-i)(2)]BF4 (13). The reaction of 13 with carbon monoxide affords [RuH(CO)(2)(NH=CPh(2))((PPr3)-Pr-i)(2)]BF4 (14).