Bis(chlorogermyliumylidene) 2 has been strategically obtained within redox-active bis(α-iminopyridine). Metal-free reduction of 2 followed by protonation led to elusive 2,3-di(pyridin-2-yl)piperazine with meso-stereoselectivity. Formation of persistent triplet diradicals upon reduction and isolation of piperazine stabilized Ge(II) dication intermediates provide convincing evidence for the crucial role of [GeCl]⁺ units in reductive cyclization.

中文翻译：

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bis（chlorogermyliumylidene）及其在难以捉摸的还原环化中的重要作用†

在具有氧化还原活性的双（α-亚氨基吡啶）中已策略性地获得了双（氯锗亚苄基）2。无金属还原2然后质子化导致难以捉摸的2,3-二（吡啶-2-基）哌嗪具有内消旋-立体选择性。还原和分离哌嗪稳定的Ge（II）药物中间体后形成的持久性三联双自由基为[GeCl] ⁺单元在还原环化中的关键作用提供了令人信服的证据。