Synthesis, characterization, and X-ray structures of three iridium(III)-hydrido-cyclometallated-imine complexes, including the first reported hydrido-(η1-imine)-Ir complex

Abstract

Reactions of cis,trans,cis-[Ir(H)2(PPh3)2(solv)2]PF6 (solv = MeOH or Me2CO) with the imines HN=CPh2, (o-HOC6H4)C(Me)=NCH2Ph, and PhC(H)=N(p-F-C6H4) in MeOH or acetone under Ar give the complexes [IrH{NH=C(Ph)(o-C6H4)}(NH=CPh2)(PPh3)2]PF6 (3), [IrH{PhCH2N=C(Me)(o-C6H3OH)}(solv)(PPh3)2]PF6, where solv = MeOH (4) or Me2CO (4a), and [IrH{N(p-F-C6H4)=CH(o-C6H4)}(Me2CO)(PPh3)2]PF6 (5a), which have been isolated and characterized. The imine (C6F5)C(H)=NPh is unreactive toward the Ir precursors. The X-ray structures of 3, 4·2MeOH, and 5a·1/2Me2CO show an η2-N,C-imine moiety coordinated via the N atom and an orthometallated-C atom. Complex 3, which contains both an orthometallated imine and an η1-imine, is the first structurally characterized hydrido-(η1-imine)-Ir complex. Comparisons are made with data for the corresponding Rh systems.Key words: iridium, hydride complexes, imines, fluoroimines, phosphine complexes, orthometallation, crystallography, NMR spectroscopy.