Tris(pyrrolyl-α-methyl)amines that sterically protect a trigonal metal site

Three substituted tris(pyrrolyl-alpha-methyl)amines (H-3[Aryl(3)TPA]) (Aryl = 2,4,6-C6H2Me3, 2,4,6-C6H2(i7Pr)(3) (Trip), or 3,5-C6H3(CF3)(2)) have been prepared. An X-ray study of [TriP(3)TPA]MoCl shows it to be a distorted trigonal bipyramidal species in which the 2,4,6-triisopropylphenyl substituents surround and protect the apical chloride. Attempts to prepare other Mo, Zr, and Hf complexes yielded species in which one pyrrole-containing arm remained free (Mo) or dimethylamine remained in the coordination sphere of [Aryl(3)TPA](3-) complexes (Zr, Hf).