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

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(mu(3)-eta(2)-OCH2CH2OMe)(eta(2)-OCH2CH2OMe)(OC6H3R2-2,6)(-)][H+]}(4) (R = Me, 2; R = 'Pr, 3). Magnetic measurements of 1-3 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(mu-eta(2)-OCH2CH2OMe)Eu(mu-eta(2)-OCH2CH2OMe)(2)AlMe2](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.