Reactions of a Triruthenium Pentahydrido Complex with Imines Leading to the Formation of a Perpendicularly Coordinated Iminoacyl Ligand and the Scission of a CN Bond on a Triruthenium Plane

The reaction of a triruthenium pentahydrido complex, {Cp*Ru­(μ-H)}3(μ3-H)2 (1; Cp* = η5-C5Me5), with N-benzylidenemethylamine resulted in the exclusive formation of a perpendicularly coordinated iminoacyl complex, (Cp*Ru)3(μ-η2:η2(⊥)-PhCNMe)­(μ-H)2 (3b), as a result of C–H bond scission of imine. However, the treatment of 1 with N-benzylideneaniline at 100 °C caused C–N bond cleavage to yield the μ3-benzylidyne−μ3-phenylimido complex (Cp*Ru)3(μ3-CPh)­(μ3-NPh)­(μ-H)2 (7c) and the μ3-methylidyne−μ3-phenylimido complex (Cp*Ru)3(μ3-CH)­(μ3-NPh)­(μ-H)2 (8). The formation of 7c is in strong contrast to the C–N bond scission occurred in (Cp*Ru)3(μ-η2:η2(⊥)-PhCNH)­(μ-H)2 (3a), which required heating at 180 °C. The structural and spectral properties of μ3-η2:η2(⊥)-nitrile complex 2, cationic μ3-η2:η2(⊥)-iminoacyl complex 6, and neutral μ3-η2:η2(⊥)-iminoacyl complex 3 revealed a clear trend of the activation of the C–N bond on a Ru3 plane. The thermolysis of 3b proceeded in a different manner to yield a μ3-methylidyne−μ3-η2(∥)-iminoacyl complex, (Cp*Ru)3(μ3-CH)­(μ3-HNCH)­(μ-H) (9), as a consequence of both C–N and C–C bond scission.三钌五氢配合物{Cp*Ru(μ-H)}₃(μ₃-H)₂（1；Cp* = η⁵-C₅Me₅，即五甲基环戊二烯基）与N-苄亚基甲胺反应后，仅生成垂直配位的亚氨酰配合物(Cp*Ru)₃(μ-η²:η²(⊥)-PhCNMe)(μ-H)₂（3b），该产物源于亚胺的C-H键断裂。然而，配合物1与N-苄亚基苯胺在100 ℃下反应时，发生C-N键断裂，生成μ₃-苄炔基−μ₃-苯亚胺基配合物(Cp*Ru)₃(μ₃-CPh)(μ₃-NPh)(μ-H)₂（7c）与μ₃-甲炔基−μ₃-苯亚胺基配合物(Cp*Ru)₃(μ₃-CH)(μ₃-NPh)(μ-H)₂（8）。配合物7c的生成与需在180 ℃下加热才可发生C-N键断裂的(Cp*Ru)₃(μ-η²:η²(⊥)-PhCNH)(μ-H)₂（3a）形成鲜明对比。μ₃-η²:η²(⊥)-腈基配合物2、阳离子型μ₃-η²:η²(⊥)-亚氨酰配合物6以及中性μ₃-η²:η²(⊥)-亚氨酰配合物3的结构与光谱性质，清晰展现了Ru₃金属平面上C-N键活化的变化趋势。对配合物3b进行热解时，反应路径有所不同，经C-N键与C-C键双重断裂，生成μ₃-甲炔基−μ₃-η²(∥)-亚氨酰配合物(Cp*Ru)₃(μ₃-CH)(μ₃-HNCH)(μ-H)（9）。