Crystal structure of a zwitterionic azaallyl zirconiumamide complex bearing a Zr⁺-μ-CH₃—B⁻ moiety and one equivalent of n-hexane as a solvent

Abstract

The zirconiumamide complex [(cyclohex-1-enyl)cyclohexylamido]bis(dicyclohexylamido)[methyltris(pentafluorophenyl)borato]zirconium(IV) hexane monosolvate, [Zr{N(C6H11)2}2{N(C6H11)(C6H9)}{BCH3(C6F5)3}]·C6H14, is zwitterionic and bears a Zr+—μ-CH3—B− moiety. The reaction of tris(dicyclohexylamido)methylzirconium with the strong Lewis acid tris(pentafluorophenyl)borane results in the formation of an azaallyl zirconium motif by the loss of H2 in one dicyclohexylamido ligand, as shown by single-crystal X-ray diffraction. The ZrIV cation is coordinated to the N atoms of two dicyclohexylamido ligands, the π-system of one azaallyl ligand, and to the μ-CH3—B unit, resulting in a distorted tetrahedral coordination environment. The Zr—N distance to the azaallyl ligand is elongated, whereas the Zr—C distance to this moiety is found to be shortened in comparison with those to the two Cy2N groups (Cy is C6H11).