Activation of ethylene and ammonia at iridium: C–H versus N–H oxidative addition

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Abstract
The ammine complexes cis-trans-[Ir(4-C5NF4)(H)2(NH3)(PiPr3)2] (3) and cis-[Ir(4-C5NF4)(H){(E)-(MeO2C)CCH(CO2Me)}(NH3)2(PiPr3)] (5) are generated on reaction of cis-trans-[Ir(4-C5NF4)(H)2(PiPr3)2] (1) or of the vinyl compound trans-[Ir(4-C5NF4)(H){(E)-(MeO2C)CCH(CO2Me)}(PiPr3)2] (4) with NH3, respectively. Photolysis of 5 gives complex [Ir(4-C5NF4)(H){κ2-(C,O)-(Z)-(MeO2C)CCH(COOMe)}(NH3)(PiPr3)] (6). Treatment of the ethylene compound trans-[Ir(4-C5NF4)(C2H4)(PiPr3)2] (2) with ammonia yields C–H activation products such as the hydrido vinyl species trans-[Ir(4-C5NF4)(H)(C2H3)(NH3)(PiPr3)2] (7) and the cyclometallation products [Ir(4-C5NF4)(H)(NH3){κ2-(P,C)-CH2CH(CH3)PiPr2}(PiPr3)] (8a, 8b). A subsequent reaction leads to the generation of the binuclear oxidative addition product of ammonia [Ir(4-C5NF4)(H)(μ-NH2)(NH3)(PiPr3)]2 (9).