(η³-Azaallyl)zirconium Chlorides: Synthesis, Characterization, and Ethylene (Co-)polymerization Activity

Abstract

Diisopropyl-N-(1-phenylvinyl)benzenamido)magnesium bromide (CH 2 (Ph)C(2,6-i Pr 2 C 6 H 3 )-NMgBr 3 2THF, 1b) reacted with 1 equiv of Me 2 NMe 2 SiCl to form the N-( 2The reaction of zirconium tetrachloride with 2 equiv of 1d produced the bisligated (η 3azaallyl)zirconium dichloride ((η 3 -(2,6-i Pr 2 C 6 H 3 )N(Ph)CCHSiMe 2 NMe 2 ) 2 ZrCl 2 , 2), whereas the stoichiometric reaction of zirconium tetrachloride with 1d formed a monoligated zirconium trichloride complex ((η 3 :η 1 -(2,6-i Pr 2 C 6 H 3 )N(Ph)CCHSiMe 2 NMe 2 )ZrCl 3 , 3), in which the ligand acted as an η 3 -azaallyl species with N-donation via the dimethylamino group at the silyl bridge. All compounds were fully characterized by elemental and spectroscopic analyses and metal compounds by single-crystal X-ray diffraction. The azaallyl groups of the ligands act in a κ 1 -enamido fashion in compounds 1b,d, while the azaallyls appear as an η 3 -N,C,C mode in compound 2. The η 3 :η 1 coordination of the azaallyl and dimethylsilyl groups provided a sterically constrained geometry around the zirconium in compound 3. The coordination geometries around each zirconium are pseudo-octahedral in both compounds 2 and 3. The modes of coordination affected their catalytic behaviors toward polymerization: high activity by 3 and good activity by 2.

Alkyl substituents triggered an unexpected formation of mono‐and dinuclear zirconium hydrazonate complexes: synthesis, characterization and their catalytic behavior toward ethylene polymerization

“…Such ligands have resulted in the discovery of numerous highly active pre‐catalysts, including bis (pyrrolide‐imine) group IV transition metal complexes (PI catalysts), bis (phenoxy‐imine) early transition metal complexes (FI catalysts), 1a, 2 bis (imino)pyridine iron and cobalt complexes, 2c, 3 α‐diimine nickel and palladium complexes, 3e, 4 and amidinate transition metal complexes . Our efforts have focused on the amidinate, β‐diketiminato and η 3 ‐azaallyl ligands for the synthesis and olefin polymerization of their metal complexes. Some of the group IV metal complexes exhibited either high activities toward ethylene polymerization or produced polyethylene with an ultra‐high molecular weight 6a–g, 7, 8 .…”

“…Our efforts have focused on the amidinate, β‐diketiminato and η 3 ‐azaallyl ligands for the synthesis and olefin polymerization of their metal complexes. Some of the group IV metal complexes exhibited either high activities toward ethylene polymerization or produced polyethylene with an ultra‐high molecular weight 6a–g, 7, 8 . Hydrazones are a class of molecules with the general formula of R 2 C=N‐NR 2 in which two nitrogen atoms of different nature are interlinked.…”

Formation of 2-Azaallyl Cobalt(I) Complexes by Csp3–H Bond Activation

“…As the structurally similar ligands, the chemistry of azaallyl ligands and their transition metal complexes has attracted much interest because of diverse bonding modes with different electronic properties brought by the substitution of the carbon atom in the allyl ligand by the N atom in the azaallyl ligand. − It can be concluded from the literature that there are several kinds of the azaallyl ligands and their coordination modes (Scheme ): ( A ) N-coordinated enamido mode, ,, ( B ) η 3 -coordinated 1-azaallyl mode, − ( C ) η 3 -coordinated 2-azaallyl mode, − and ( D ) η 3 -coordinated 1,3-diazaallyl mode , (Scheme ).…”

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

“…data reports of general interest, but azaallyl metal complexes seem to be an acceptable compromise, particularly due to their different bonding modes, from 1 -enamido (1 A) up to 3 -azaallyl moieties (1B) (Yuan et al, 2010;Fig. 1).…”