Synthesis and reactivity of ruthenium amide-phosphine complexes. Facile conversion of a ruthenium amide to a ruthenium amine via dihydrogen activation and ortho metalation. X-ray structure of RuCl(C6H4PPh2)[NH(SiMe2CH 2PPh2)2]

Article abstract of DOI:10.1021/om00048a025

The reaction of LiN(SiMe₂CH₂PPh₂)₂ with RuCl₂(PPh₃)₃ leads to the formation of the ruthenium amide complex RuCl(PPh₃)[N(SiMe₂CH₂PPh₂) ₂]. This complex reacts with H₂ to form two isomeric amine-hydride derivatives of the formula RuCl(PPh₃)H[NH(SiMe₂CH₂PPh₂) ₂]. Reaction of RuCl(PPh₃)[N-(SiMe₂CH₂PPh₂) ₂] with MeLi, Me₃SiCH₂Li, or H₂C=CHCH₂MgCl does not lead to the expected hydrocarbyl derivative; rather, ortho metalation occurs to generate Ru(C₆H₄PPh₂)[N(SiMe₂CH ₂PPh₂)₂]. Attempts to displace the PPh₃ ligand of RuCl(PPh₃)[N(SiMe₂CH₂PPh₂) ₂] with PEt₃ lead to the formation of RuCl-(C₆H₄PPh₂)[NH(SiMe₂PPh ₂)₂], having an amine ligand and the ortho-metalated phenyl group. The complex RuCl(C₆H₄PPh₂)[NH(SiMe₂CH ₂PPh₂)₂] crystallizes in space group P2₁/n with a = 9.8385 (5) ?, b = 29.561 (1) ?, c = 20.8665 (9) ?, β = 101.683 (4)°, V = 5942.2 (5) ?³, and Z = 4. Transformation of an amide linkage to an amide via H₂ activation or ortho metalation is apparently driven by the formation of an intramolecular hydrogen bond between the amine hydrogen and the coordinated chloride; the N-H?Cl distance is 2.76 (6) ?, which is shorter than the expected van der Waals separation of 3.0 ?.