Utility of 2-Methoxyethanol in the Synthesis of Polyeuropium Complexes: {[Eu(OCH 2 CH 2 OMe) 2 (OC 6 H 3 R 2 -2,6) - ][H + ]} 4 (R = Me, i Pr) and [EuAl 2 (OCH 2 CH 2 OMe) 3 Me 5 ] 2
1998; American Chemical Society; Volume: 37; Issue: 20 Linguagem: Inglês
10.1021/ic9803311
ISSN1520-510X
AutoresWilliam J. Evans, M.A. Greci, Joseph W. Ziller,
Tópico(s)Lanthanide and Transition Metal Complexes
ResumoEuropium 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(μ3-η2-OCH2CH2OMe)(η2-OCH2CH2OMe)(OC6H3R2-2,6)-][H+]}4 (R = Me, 2; R = iPr, 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(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.
Referência(s)