Monomeric and Linear Polymeric Samarium(II) Complexes of the 2-(N-Arylimino)pyrrolide Ligand

Abstract

The synthesis and structural characterization of monomeric and linear polymeric divalent samarium complexes as well as their related trivalent species supported by an (imino)pyrrolide ligand are described. The divalent samarium 2-(N-arylamino)pyrrolide complex [NN]2Sm(THF)2 (1) was prepared by the reaction of SmI2(THF)2 with 2 equiv of [NN]K ([NN] = [2-(2,6-iPr2C6H3NCH)-5-tBuC4H2N]−) in THF. Upon treatment of 1 with dry oxygen, the oxo-bridged dimer [NN]2Sm(μ-O)Sm[NN]2 (2) was generated. Reaction of [NN]2SmCH2SiMe3 (3) with 3 equiv of AlEt3 in n-hexane gave the samarium aluminate [NN]2Sm(μ-Et)2AlEt2 (4). Reduction of 4 with potassium in toluene yielded the linear polymeric species {[NN]2SmAlEt4K(C7H8)} n (5). Compounds 1, 2, 4, and 5 have been characterized by X-ray single-crystal analysis. 5 features a linear polymeric structure, in which the potassium ion links the neighboring monomeric samarium moieties via η2 and η5 coordination to the pyrrolide rings in the two different units, with one toluene molecule and one of the ethyl groups of the [AlEt4] anion being also η2 coordinated to the potassium to complete its coordination sphere.

Synthesis of Rare-Earth-Metal Iminopyrrolyl Complexes from Alkyl Precursors: Ln→Al N-Ancillary Ligand Transfer

“…Later on, Ln(III) hydrocarbyl derivatives with N,N-bidentate iminopyrrolyl have been exploited for the polymerization of methyl methacrylate (samarium), lactide (yttrium), and isoprene (scandium, yttrium, lanthanum) . Salt metathesis and amine , and alkane elimination, , as well as a AlEt 3 -redox addition involving Ln(CH 2 SiMe 3 ) 3 (thf) 2 and a divalent Sm(II) iminopyrrolyl complex, respectively, have so far been applied as the main synthesis protocols.…”

Potassium–Alkane Interactions within a Rigid Hydrophobic Pocket

“…[15,16] The potassium-alkane interaction in 1 can be surmised to involve a weak electrostatic (primarily cationinduced dipole) [17] potassium-alkane interaction stabilized by interactions between the alkane and the hydrophobic ligand pocket.…”

Synthesis, Characterization and Biological Activity of Polymer Nickel (Ii) Complex

“…Late transition metal complexes [1] , , due to their less oxophilic nature relative to early transition metal complexes [2] and lanthanide metal complexes [3], are generally considered to be more tolerant toward polar functional monomer, which makes them likely targets to the development of catalysts for the polymerization of polar monomers including methyl methacrylate (MMA). Nickel (II) complexes bearing N, O-chelate ligand activation for MMA polymerization yielded poly (methyl methacrylate) (PMMA) with rich syndiotacticity microstructure [4][5][6][7][8][9][10].…”