Di‐ and Trivalent Lanthanide Complexes Stabilized by Sterically Demanding Aminopyridinato Ligands

Deprotonation of Ap*H {Ap*H = (2,6-diisopropylphenyl)-[6-(2,4,6-triisopropylphenyl)pyridin-2-yl]amine} and Ap'H {Ap'H = (2,6-diisopropylphenyl)-[6-(2,6-dimethylphenyl)pyridin-2-yl]amine} using KH leads to polymeric [Ap*K]n and [Ap'K]n which undergo clean salt metathesis reactions with NdCl3 in THF forming [Nd(Ap*)Cl2(THF)2]2 and [Nd(Ap')2-Cl(THF)], respectively. Ethylene polymerization activities of the two chloro complexes (after activation with MAO) were studied. Derivatization of the chloro compounds proceeds without ate complex formation, for instance the reaction of [Nd(Ap')2Cl(THF)] with one equiv. of [K{N(SiMe3)2}] leads to the “THF-free” silylamide [Nd(Ap')2{N(SiMe3)2}]. Furthermore rare examples of heteroleptic amido-iodo complexes of selected divalent lanthanides can be stabilized by deprotonated Ap*H. Reaction of [Ap*K]n with [LnI2(THF)3] (Ln = Yb, Sm) in THF leads, after workup in hexane, to [Yb(Ap*)I-(THF)2]2 and [Sm(Ap*)I(THF)2]2. All lanthanide complexes, four of them are paramagnetic, were characterized by X-ray crystal structure analysis. These compounds exhibit an excellent solubility in nonpolar solvents like hexane. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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