Synthesis and Crystal Structures of Bulky Guanidinato Zirconium(IV) and Hafnium(IV) Chloride Complexes

Abstract

Reactions of in situ generated [Li(Giso)] (Giso = [(DipN)₂CN(C₆H₁₁)₂]⁻; Dip = C₆H₃Pr ⁱ₂ -2,6) with either ZrCl₄ or HfCl₄ led to the complexes [(Giso)MCl₃] (M = Zr 1 or Hf 2). Reduction of [(Giso)ZrCl₃] with an excess of magnesium metal in THF afforded a small isolated yield of the THF insertion product, [{(Giso)ZrCl(μ-OC₄H₈)}₂]. The crystal structures of all complexes have been determined. The cell parameters of the compounds are 1 (toluene)_0.5: P-1, a = 10.961(2), b = 11.046(2), c = 19.668(4), α = 75.31(3), β = 76.69(3), γ = 61.93(3); 2 (toluene)_0.5: P-1, a = 10.949(2), b = 11.037(2), c = 19.621(4), α = 75.29(3), β = 76.80(3), γ = 61.90(3); 3 (hexane)₂: P2₁/c, a = 14.424(3), b = 16.950(3), c = 20.330(4), β = 109.09(3). The crystal structures of 1 and 2 are the first for five-coordinate, monomeric guanidinato group 4 metal trihalide complexes.

Graphical Abstract

The crystal structures of three bulky guanidinato group 4 chloride complexes, [(Giso)MCl₃] (M = Zr or Hf) and [{(Giso)ZrCl(μ-OC₄H₈)}₂] (Giso = [(DipN)₂CN(C₆H₁₁)₂]⁻; Dip = C₆H₃Pr ⁱ₂ -2,6), are reported.