Synthesis of a new olefin polymerization catalyst supported by an sp3-C donor via insertion of a ligand-appended alkene into the Hf–C bond of a neutral pyridylamidohafnium trimethyl complex

Abstract

A new living and isoselective propylene polymerization precatalyst was generated via the intramolecular insertion of a ligand-appended vinyl group into the Hf-C bond of a neutral pyridylamidohafnium trimethyl complex.

Yttrium‐Amidopyridinate Complexes: Synthesis and Characterization of Yttrium‐Alkyl and Yttrium‐Hydrido Derivatives

“…The aqueous phase was extracted with AcOEt (3 ϫ 20 mL) and the combined organic layers were dried with Na 2 SO 4 . Removal of the solvent under reduced pressure gave the amidopyridinate ligands (6)(7)(8)(9)(10) as crude off-white solids. The ligands were purified by crystallization from hot MeOH by cooling the resulting solution at either 4°C (6,8,10) or -20°C (7, 9) overnight to afford crystals.…”

“…Removal of the solvent under reduced pressure gave the amidopyridinate ligands (6)(7)(8)(9)(10) as crude off-white solids. The ligands were purified by crystallization from hot MeOH by cooling the resulting solution at either 4°C (6,8,10) or -20°C (7, 9) overnight to afford crystals. Suitable crystals for X-ray diffraction were collected after successive recrystallization from hot MeOH.…”

“…All structures consist of a central pyridine unit substituted at its 6-position by an aryl (Figure 2, ligands 6 and 7) or a heteroaryl (Figure 2, ligands 8-10) group and at its 2-position by the same amine-containing C(Me) 2 NH(2,6-iPr 2 C 6 H 3 ) fragment. The aryl or heteroaryl moieties are almost coplanar with respect (6), N 2 H Xyl (7), N 2 H Th (8), N 2 H EtTh (9) and N 2 H BFu (10). Thermal ellipsoids are drawn at the 30 % probability level.…”

“…The incorporation of sp 3 -C donors into the imidopyridinate ligand framework has been successfully achieved by Coates and co-workers through an intramolecular migratory insertion of a cationic Hf IV species onto a facing vinyl moiety (Figure 1b). [10] Although inter-and intramolecular metalations of sp 2 -and sp 3 -hybridized C-H bonds have been previously documented for cyclopentadienyl [3b,11] and cyclopentadienyl-free [4b,12] lanthanide-alkyl and -hydride complexes, they still attract considerable interest due to the intrinsic difficulty for organometallic fragments to activate inert chemical bonds. In this paper we provide a full account on the synthesis, characterization and catalytic activity of a family of novel yttrium(III)-alkyl and -hydrido complexes distinguished by stable Y-C(aryl) or Y-C(heteroaryl) bonds.…”

Dimethyl-Aluminium Complexes Bearing Naphthyl-Substituted Pyridine-Alkylamides as Pro-Initiators for the Efficient ROP of ε-Caprolactone

“…Moreover, functionalizing the 6-position of the pyridine moiety of the pyridylimine with an aryl or 1-naphthyl group presents a versatile set of substrates for studying ortho vs. peri-palladation reactions during the formation of N,N,C-chelates [53,54]. Likewise, N,N-pyridyl-alkylamides and their 6-aryl and -naphthyl derivatives have also been attracting attention due, in large measure, to their emergence as supports for exceptionally active N,N- [45,55,56] and N,N,C-bound group 4 olefin polymerization catalysts [57][58][59][60].…”