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, C31H31N2OP, is reported. Bridge cleavage of {MCl(μ-Cl)(η5 -Cp*)}2 (M=Ir, Rh) with 2 equiv. of 1 in CH2Cl2 gave the mononuclear compounds [MCl2(η5 -Cp*)(P-1)] (M=Ir, 2a; M=Rh, 2b) in which 1 functions as a P-monodentate ligand. Rapid C(sp3 ) H bond activation, at room temperature, is observed for 2a leading to the unusual cyclometallated complex [Ir(η5 -Cp*)(P,N,C-1)]Cl2 3 (or 3‘) bearing an anionic P/Namine/C-terdentate ligand. Reaction of [Pt(CH3) Cl(η4 -cod)] with one equiv. of 1 led to [Pt(CH3)Cl(P,N-1)] 4, suggesting that 3 may form via an intermediate IrIII cationic species in which the ligand is P,N-bound. The IrI complex [IrCl (η4 -cod)(P-1)] 5 does not, under similar conditions, show any evidence for C H activation. Single crystal X-ray studies on 1, 2a, 2b, 3, 3‘, 4, and 5 reveal intramolecular N···H O H-bonding in all cases.