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(mu-Cl)(eta(5)-Cp*)}(2) (M=Ir, Rh) with 2 equiv. of 1 in CH2Cl2 gave the mononuclear compounds [MCl2(eta(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(eta(5)-Cp*)(P,N,C-1)]Cl-2 3 (or 3') bearing an anionic P/N-amine/C-terdentate ligand. Reaction of [Pt(CH3)Cl(eta(4)-cod)] with one equiv. of 1 led to [Pt(CH3)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(eta(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.