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Utility of 2-Methoxyethanol in the Synthesis of Polyeuropium Complexes:  {[Eu(OCH2CH2OMe)2(OC6H3R2-2,6)-][H+]}4 (R = Me, iPr) and [EuAl2(OCH2CH2OMe)3Me5]2

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posted on 1998-09-10, 00:00 authored by William J. Evans, Michael A. Greci, Joseph W. Ziller
Europium reacts with 2-methoxyethanol at room temperature to form arene-soluble [Eu(OCH2CH2OMe)2]n, 1. Reaction of 1 with 2,6-dimethylphenol or 2,6-diisopropylphenol forms the tetrametallic complexes {[Eu(μ32-OCH2CH2OMe)(η2-OCH2CH2OMe)(OC6H3R2-2,6)-][H+]}4 (R = Me, 2; R = iPr, 3). Magnetic measurements of 13 in solution are consistent with the presence of divalent europium. 2 and 3 are isostructural and contain a tetrahedral arrangement of europium atoms. Coordinated to each seven-coordinate metal are one terminal bidentate alkoxide, one bridging bidentate alkoxide, which bridges through its alkoxide oxygen to two other europium atoms, a terminal aryloxide, and two bridging oxygen atoms from other such units. The presence of protons in 2 was probed by reaction with Al2Me6, which forms hexametallic [Me3Al(μ-η2-OCH2CH2OMe)Eu(μ-η2-OCH2CH2OMe)2AlMe2]2, 4. Each six-coordinate europium in 4 is surrounded by three bidentate 2-methoxyethoxide ligands, which bridge via their alkoxide oxygen atoms. One ligand bridges to one AlMe3 unit, and the other two ligands bridge to AlMe2 units.

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