We report that the use of a hydrogen-bonded pyrimidine-macrocycle complex can efficiently facilitate the threading of two bispyridinium ethylenes into four rings, as evidenced by X-ray crystallography of its precursor, offering a rare example of a doubly threaded [6]rotaxane in 91% yield. The unusual architecture is found to be stable with no dethreading despite the large ring size of the macrocycle with respect to the stopper.

中文翻译：

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分子束：双螺纹[6]轮烷

我们报告说，使用氢键嘧啶大环配合物可以有效地促进两个双吡啶乙烯连接成四个环，正如其前体的X射线晶体学所证明的那样，这提供了双螺纹[6]轮烷的罕见例子产率91%。尽管大环相对于塞子的环尺寸较大，但这种不寻常的结构被发现是稳定的，没有脱螺纹。