Oxidative insertion into the N–H bond of carbazole, indole and pyrrole with zerovalent metals

The reactions of carbazole (C12H8NH), indole (C8H6NH) and pyrrole (C4H4NH) with the zerovalent [Pt(PEt3)3], [Pd(PEt3)3] and [Ni(PEt3)3] gave oxidative insertion into the N–H bond, affording the corresponding hydrides of the type trans-[HM(LN)(PEt3)2], LN=de-protonated heterocyclic ligand; the isolated compounds for platinum were trans-[HPt(C8H6N)(PEt3)2] (1), trans-[HPt(C4H4N)(PEt3)2] (2), and for nickel trans-[HNi(C12H8N)(PEt3)2] (3), trans-[HNi(C8H6N)(PEt3)2] (4) and trans-[HNi(C4H4N)(PEt3)2] (5); on using palladium the corresponding hydrides were also detected in solution, however, after longer reaction time the double substituted compounds: trans-[Pd(C12H8N)2(PEt3)2] (6), trans-[Pd(C8H6N)2(PEt3)2] (7) and trans-[Pd(C4H4N)2(PEt3)2] (8) were obtained. A crystal structure is reported for 6.