Oxidative addition reactions of alkyl halides with the group 13 carbene analogue [In{N(Dipp)C(Me)}₂CH] (Dipp = 2,6-ⁱPr ₂C₆H₃)

Reactions of the well-defined two-coordinate indium "carbene analogue" [In{N(Dipp)-C(Me)}₂CH] (Dipp = 2,6-ⁱPr ₂C₆H₃) have been studied. Reactions of Mel, ⁱPrl, and ^tBul with [In{N(Dipp)C(Me)}₂CH] formed by the in situ reaction of InI, [K{N(SiMe₃)₂}], and the iminoenamine ligand precursor successfully yielded the oxidative addition products [InRI{N(Dipp)C(Me)}₂CH] (R = Me, ⁱPr, ^tBu). The results of NMR investigations, which indicated the formation of a series of four-coordinate indium(III) complexes in C ₆D₆ solution, were confirmed in the solid-state by single-crystal X-ray diffraction. Similar reactions employing alkyl bromides were unsuccessful and resulted in the isolation of the corresponding iodides, apparently by metathesis of the bromide oxidative addition product with Kl formed during the initial InI metathesis. Reactions of isolated samples of [In{N(Dipp)C(Me)}₂CH] with ⁱPrBr and ^tBuBr, however, were straightforward and resulted in the successful isolation of the analogous iso-propyl and tert-butyl indium(III) bromide complexes. These were also fully characterized by ¹H and ¹³C NMR and single-crystal X-ray diffraction experiments. In contrast, no reaction was observed between [In{N(Dipp)-C(Me)}₂CH] and aryl halides or alkyl chlorides.