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

Abstract

The one-step synthesis (44 % isolated yield) of the 1,5benzodiazapine 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 )À 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 CÀ H activation. Single crystal X-ray studies on 1, 2 a, 2 b, 3, 3', 4, and 5 reveal intramolecular N ••• HÀ O H-bonding in all cases.