Abstract The CH2–O–C2H4–O–CH2 moieties in Lehn’s cryptand [2.2.2] have been substituted by 2,2′-bifurane groups to get the cryptand [bfu.bfu.bfu]. The ion selectivity of this new cryptand was investigated by DFT calculations (RB3LYP/LANL2DZp, RB3LYP/LACVP*, RBP86/LANL2DZp and RBP86/LACVP*) based on model equations and analysis of the [M ⊂ bfu.bfu.bfu] n+ cryptate structures. The cryptand [bfu.bfu.bfu] is best suited for the alkali cations Na+ and K+, and the alkaline earth cation Sr2+ followed by Ca2+. The cavity of [bfu.bfu.bfu] is thus similar to that in [phen.phen.phen] or [bpy.bpy.bpy]. The selectivity of [bfu.bfu.bfu] is due to the flexibility of the OCCO und CN···NC dihedral angles. The results are independent of the selected DFT methods.

中文翻译：

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Wirt-Gast-Komplexe von [bfu.bfu.bfu]: Vorhersage von Ionenselektivitäten mittels quantenchemischer Rechnungen XIII

摘要 Lehn's cryptand [2.2.2] 中的CH2-O-C2H4-O-CH2 部分已被2,2'-双呋喃基团取代，得到了cryptand [bfu.bfu.bfu]。基于模型方程和 [M ⊂ bfu.bfu.bfu] n+ 穴状化合物的 DFT 计算（RB3LYP/LANL2DZp、RB3LYP/LACVP*、RBP86/LANL2DZp 和 RBP86/LACVP*）研究了这种新穴状体的离子选择性结构。cryptand [bfu.bfu.bfu] 最适合碱金属阳离子 Na+ 和 K+，以及碱土金属阳离子 Sr2+，其次是 Ca2+。[bfu.bfu.bfu] 的空腔因此类似于 [phen.phen.phen] 或 [bpy.bpy.bpy] 中的空腔。[bfu.bfu.bfu] 的选择性是由于 OCCO 和 CN...NC 二面角的灵活性。结果与所选的 DFT 方法无关。