X-ray diffraction measurements and quantum-chemical calculations of the crystal structures of nitromethylcytisines were performed. N-allylamide-9-nitrocytisine (III) was compared to previously studied N-methyl-9-nitrocytisine (II). The crystal structure of III was stabilized as a result of participation of the amide in relatively strong N–H···OH-bonds. The packing density of crystals of III was higher than that of II. Compound III had a significantly higher melting point, in agreement with our previously suggested positive correlation between the packing density and melting point. Compound III was readily soluble in water, in contrast to II, because of a substantial role of specific solvation effects.

中文翻译：

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N-Allylamide-9-Nitrocytisine的分子和晶体结构

对硝基甲基胞嘧啶的晶体结构进行了 X 射线衍射测量和量子化学计算。N-allylamide-9-nitrocytisine (III) 与先前研究的 N-methyl-9-nitrocytisine (II) 进行了比较。由于酰胺参与相对强的 N-H···OH-键，III 的晶体结构得到稳定。III类晶体的堆积密度高于II类。化合物 III 具有明显更高的熔点，这与我们之前提出的堆积密度和熔点之间的正相关性一致。与 II 相比，化合物 III 易溶于水，这是因为特定溶剂化效应的重要作用。