Tris(pyrrolyl-alpha-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-C(6)H(2)Me(3), 2,4,6-C(6)H(2)(i-Pr)(3) (Trip), or 3,5-C(6)H(3)(CF(3))(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).