The successful mono‐ and diprotonation of DAMN showed the first site of protonation to be an amino group, while the second protonation occurs at a nitrile group. The prepared salts were characterized by vibrational spectroscopy and single crystal X‐ray crystallography. Under strong superacidic conditions and with sufficient time cyclization of two (di)protonated molecules of DAMN is observed, yielding a tetracationic pyrazine species. Quantum chemical calculations are employed to explain reactivity and properties of compounds shown in the manuscript.

中文翻译：

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二氨基马来腈 – 单质子化、二质子化……和四质子化？！

DAMN 的成功单质子化和双质子化表明质子化的第一个位点是氨基，而第二个质子化发生在腈基处。通过振动光谱和单晶X射线晶体学对制备的盐进行了表征。在强超酸条件下，在足够的时间下，观察到 DAMN 的两个（二）质子化分子发生环化，产生四阳离子吡嗪类物质。采用量子化学计算来解释手稿中所示化合物的反应性和性质。