Zirconium and Hafnium Complexes Containing Bidentate Diarylamido−Phosphine Ligands

The first examples of mononuclear, structurally characterized triarylphosphine complexes of zirconium and hafnium
are reported. The metathetical reactions of MCl4(THF)2 (M = Zr, Hf) with [iPrNP]Li(THF)2 ([iPrNP]- =
N-(2-(diphenylphosphino)phenyl)-2,6-diisopropylanilide) or [MeNP]Li(THF)2 ([MeNP]- = N-(2-(diphenylphosphino)phenyl)-2,6-dimethylanilide) in toluene at −35 °C produced the corresponding [iPrNP]MCl3(THF) and [MeNP]2MCl2,
respectively, in high yield. In contrast, attempts to prepare [MeNP]MCl3(THF) and [iPrNP]2MCl2 led to the concomitant
formation of mono- and bis-ligated complexes, from which purification proved rather ineffective. The solution and
solid-state structures of [iPrNP]MCl3(THF) and [MeNP]2MCl2 were studied by multinuclear NMR spectroscopy and
X-ray crystallography. The geometry of these six-coordinate complexes is best described as a distorted octahedron
in which the chloride ligands in [iPrNP]MCl3(THF) adopt a virtually meridional coordination mode whereas those in
[MeNP]2MCl2 are trans to each other.