om9001236_si_005.cif (21.94 kB)

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

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posted on 25.05.2009 by Jingjun Hao, Haibin Song, Chunming Cui
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.