Aluminate Samarium(II) and Samarium(III) Aryloxides. Isolation of a Single-Component Ethylene Polymerization Catalyst

Proton exchange reaction of isolated or in situ prepared heterobimetallic peralkylated Sm complexes with sterically demanding mono- and bisphenols led to the formation of aluminum alkyl samarium-aryloxide adducts in good yields. Divalent complexes formulated as Sm[(μ-2,6-bis(phenylphenoxy))]2[(μ-Me)(AlMe2)]2 (1), (Sm{μ-η6′-[6,6′-methylene-bis(2-tert-butyl-4-methylphenoxy)][AlMe2]}{μ-Me}2{AlMe})(μ-Me) (3), {Sm-μ-[6,6′-methylenebis(2-tert-butyl-4-methylphenol)][μ-Me2AlMe2]}2 (6), and Sm-{μ-[6,6′-methylenebis(2-tert-butyl-4-methylphenoxy)]}2-μ-AlMe2 (7) were isolated and characterized including via solid structure determination. The reactivity of these compounds toward both oxidation and insertion into the [Sm−Me−Al] fragment was probed with both CO2 and tert-butylisocyanate, affording Sm{[(μ-2,6-bis(phenylphenoxy))2AlMe2]-[μ-(acetato)-(2,6-bis(phenylphenoxy))AlMe2][1,2-dimethoxyethane]}{C6H14}0.25 (2) and Sm{μ-[6,6′-methylenebis(2-tert-butyl-4-methylphenol)]-μ-[N-tert-butylacetamidate]AlMe}2{C7H8}1.5 (4), respectively. The trivalent 6 exhibited significant activity as a catalyst for ethylene polymerization without the need for further activation and which may be regarded as an example of a single-component lanthanide ethylene polymerization catalyst without a cyclopentadienyl ligand.