Competitive Activation of a Methyl C−H Bond of Dimethylformamide at an Iridium Center

During the synthesis of [AsPh4][Ir(CO)2I3Me] by refluxing IrCl3·3H2O in DMF (DMF = dimethylformamide) in the presence of aqueous HCl, followed by sequential treatment with [AsPh4]Cl, NaI, and methyl iodide and finally recrystallization from methylene chloride/pentane, three crystalline byproducts were obtained: [AsPh4]2[Ir(CO)I5], [AsPh4]2[trans-Ir(CO)I4Cl], and [AsPh4][Ir(CO)(κ2O,C-CH2NMeCHO)Cl2I]. The last of these, whose structure (along with the others) was determined by X-ray diffraction, results from activation of a methyl C−H bond of dimethylformamide, rather than the normally much more reactive aldehydic C−H bond.