A Novel Trisamidophosphine Ligand and Its Group(IV) Metal Complexes

A novel
trisamidophosphine ligand scaffold has been synthesized
and employed to coordinate all of the group­(IV) metals. The resulting
complexes feature closed half-cage
geometries with the phosphorus donor and all three amides binding
to the metal. Out of nine complexes of the type [PN3]­MX
(M = Ti, Zr, Hf; X = NMe2, OTf, CH3), the zirconium
derivatives have been studied by X-ray diffraction and shown to exhibit
metal–phosphorus distances that are well in range of a coordinative
bond. In contrast to its heavier homologues, the titanium methyl species
[PN3]­TiMe is prone to thermally induced ligand CH activation
with concomitant loss of methane.