Tantalum amido and imido complexes supported by tris[(2-indolyl)methyl]amine, a tetradentate trianionic ligand with reduced π-donor character

Article abstract of DOI:10.1021/ic026182a

Tris[(2-indole)methyl]amine, N(CH₂inH)₃, may be readily obtained by reaction of methyl 2-bromomethyl-1-indolecarboxylate with NH₃ followed by deprotection with NaOMe/MeOH. In its deprotonated form, [N(CH₂in)₃]^3- is an efficient tetradentate trianionic ligand for tantalum, as illustrated by the isolation and structural characterization of [η⁴-N(CH₂in)₃]Ta(NAr)(NMe₂H) (Ar = 2,6-C₆H₃Prⁱ₂), [η⁴-N(CH₂in)₃]Ta (NMe₂)₂ and [η⁴-N(CH₂in)₃]Ta(NMe₂)Cl. The [N(CH₂in)₃]^3- ligand has a structural similarity to that of [N(CH₂CH₂NR)₃]^3-, but differs electronically from the latter due to its reduced π-donor capability, a direct result of the nitrogen being a component of the aromatic π-system of the indolyl fragment.