New and versatile routes to zirconium imido dichloride compounds

Abstract

Reactions of zirconium dialkyl- or bis(amido)-dichloride complexes “[Zr(CH₂SiMe₃)₂Cl₂(Et₂O)₂]” or [Zr(NMe₂)₂Cl₂(THF)₂] with primary alkyl and aryl amines are described. Reaction of “[Zr(CH₂SiMe₃)₂Cl₂(Et₂O)₂]” with RNH₂ in THF afforded dimeric [Zr₂(μ-NR)₂Cl₄(THF)₄] (R = 2,6-C₆H₃ⁱPr₂ (1), 2,6-C₆H₃Me₂ (2) or Ph (3)), [Zr₂(μ-NR)₂Cl₄(THF)₃] (R = ^tBu (5), ⁱPr (6), CH₂Ph (7)), or the “ate” complex [Zr₂(μ-NC₆F₅)₂Cl₆(THF)₂{Li(THF)₃}₂] (4, the LiCl coming from the in situ prepared “[Zr(CH₂SiMe₃)₂Cl₂(Et₂O)₂]”). With [Zr(NMe₂)₂Cl₂(THF)₂] the compounds [Zr₂(μ-NR)₂Cl₄(L)_x(L′)_y] (R = 2,6-C₆H₃ⁱPr₂ (8), 2,6-C₆H₃Me₂ (9), Ph (10) or C₆F₅ (11); (L)_x(L′)_y = (NHMe₂)₃(THF), (NHMe₂)₂(THF)₂ or undefined), [Zr₂(μ-N^tBu)₂Cl₄(NHMe₂)₃] (12) and insoluble [Zr(NR)Cl₂(NHMe₂)]_x (R = ⁱPr (13) or CH₂Ph (14)) were obtained. Attempts to form monomeric terminal imido compounds by reaction of 2 or 5 with an excess of pyridine led, respectively, to the corresponding dimeric adducts [Zr₂(μ-2,6-C₆H₃Me₂)₂Cl₄(py)₄] (15) and [Zr₂(μ-N^tBu)₂Cl₄(py)₃] (16). The X-ray structures of 1, 2, 4, 8, 12 and 15 have been determined.