Heterometallic Europium Disiloxanediolates: Synthesis, Structural Diversity, and Photoluminescence Properties

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• 作者：Janek Rausch ; Volker Lorenz ; Cristian G. Hrib ; Vanessa Frettl枚h ; Matthias Adlung ; Claudia Wickleder ; Liane Hilfert ; Peter G. Jones ; Frank T. Edelmann
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：November 3, 2014
• 年：2014
• 卷：53
• 期：21
• 页码：11662-11674
• 全文大小：848K
• ISSN：1520-510X

文摘

This contribution presents a full account of a structurally diverse class of heterometallic europium disiloxanediolates. The synthetic protocol involves in situ metalation of (HO)SiPh₂OSiPh₂(OH) (1) with either ⁿBuLi or KN(SiMe₃)₂ followed by treatment with EuCl₃ in suitable solvents such as 1,2-dimethoxyethane (DME) or tetrahydrofuran (THF). Reaction of EuCl₃ with 2 equiv of (LiO)SiPh₂OSiPh₂(OLi) in DME afforded the Eu^III bis(disiloxanediolate) 鈥渁te鈥?complex [{(Ph₂SiO)₂O}₂{Li(DME)}₃]EuCl₂ (2), which upon attempted reduction with Zn gave the tris(disiloxanediolate) [{(Ph₂SiO)₂O}₃{Li(DME)}₃]Eu (3). Treatment of EuCl₃ with (LiO)SiPh₂OSiPh₂(OLi) in a molar ratio of 1:2 yielded both the ate complex [{(Ph₂SiO)₂O}₃Li{Li(THF)₂}{Li(THF)}]EuCl路Li(THF)₃ (4) and the LiCl-free europium(III) complex [{(Ph₂SiO)₂O}₂{Li(THF)₂}₂]EuCl (5). Compound 5 was found to exhibit a brilliant red triboluminescence. When (KO)SiPh₂OSiPh₂(OK) was used as starting material in a 3:1 reaction with EuCl₃, the Eu^III tris(disiloxanediolate) [{(Ph₂SiO)₂O}₃{K(DME)}₃]Eu (6) was isolated. Attempted ligand transfer between 5 and (DAD^Dipp)₂Ba(DME) (DAD^Dipp = N,N鈥?bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene) afforded the unique mixed-valent Eu^III/Eu^II disiloxanediolate cluster [(Ph₂SiO)₂O]₆Eu^II₄Eu^III₂Li₄O₂Cl₂ (7). All new complexes were structurally characterized by X-ray diffraction. Photoluminescence studies were carried out for complex 5 showing an excellent color quality, due to the strong ⁵D₀鈫?sup>7F₂ transition, but a weak antenna effect.