Synthesis and Characterisation of Transition Metal Complexes of a Novel 1,5‐benzodiazepine‐Functionalised Tertiary Phosphine

The one‐step synthesis (44 % isolated yield) of the 1,5‐benzodiazapine functionalised phosphine 1 , C 31 H 31 N 2 OP, is reported. Bridge cleavage of {MCl(μ‐Cl)(η 5 ‐Cp*)} 2 (M=Ir, Rh) with 2 equiv. of 1 in CH 2 Cl 2 gave the mononuclear compounds [MCl 2 (η 5 ‐Cp*)( P‐ 1 )] (M=Ir, 2 a ; M=Rh, 2 b ) in which 1 functions as a P ‐monodentate ligand. Rapid C(sp 3 )−H bond activation, at room temperature, is observed for 2 a leading to the unusual cyclometallated complex [Ir(η 5 ‐Cp*)( P,N,C‐ 1 )]Cl 2 3 (or 3‘ ) bearing an anionic P / N amine / C ‐terdentate ligand. Reaction of [Pt(CH 3 )Cl(η 4 ‐cod)] with one equiv. of 1 led to [Pt(CH 3 )Cl( P,N ‐ 1 )] 4 , suggesting that 3 may form via an intermediate Ir III cationic species in which the ligand is P,N ‐bound. The Ir I complex [IrCl(η 4 ‐cod)( P‐ 1 )] 5 does not, under similar conditions, show any evidence for C−H activation. Single crystal X‐ray studies on 1 , 2 a , 2 b , 3 , 3‘ , 4 , and 5 reveal intramolecular N ⋅⋅⋅ H−O H‐bonding in all cases.