Abstract Zwitter-ions of 3-(1,1,1-trimethylhydrazin-1-ium-2-yl)propanoate make head-to-tail dimers stabilized by N–H⋯O bonds; hydrogen bonding via water molecules results in an infinite chain (monohydrate, 1 ) or in a 3D network (dihydrate, 2 ). Hydrogen bonds in protonated form (2-(2-carboxyethyl)-1,1,1-trimethylhydrazinium) create an infinite chain (chloride, 3 ) or a 2D network (fumarate, 4 ). All these crystals are stabilized by weak C–H⋯A interactions. The crystallographic parameters at − 100 °C are as follows: 1 : triclinic, space group P $$\stackrel{-}{1}$$ 1 - ; a, b, c (Å): 7.3360(5), 8.0667(5), 8.9416(6); α = 99.752(4), β = 112.665(4), γ = 107.300(4)°,V = 441.32(5) Å 3 , Z = 2; 2 : monoclinic, space group P 2 1 / c; a, b, c (Å): 6.8854(4), 11.2483(7), 12.8254(8), β = 105.339(2) °, V = 957.93(10) Å 3 , Z = 4; 3 : monoclinic, space group P 2 1 / n; a, b, c (Å): 7.3625(4), 12.6486(7), 10.5211(6), β = 103.583(2)°, V = 952.38(9) Å 3 , Z = 4; 4 : monoclinic, space group P 2 1 / c; a, b, c (Å): 6.3669(6), 29.516(3), 6.8145(7), β = 91.009(5) °, V = 1280.4(2) Å 3 , Z = 4. Structure 2 is practically identical to that already measured at room temperature. Graphical Abstract In crystal state, zwitter-ions and protonated cations of meldonium are assembled via networks of hydrogen bonds

中文翻译：

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米屈肼 (3-(1,1,1-Trimethylhydrazin-1-ium-2-yl)propanoate) 晶体的构建：X 射线视图

摘要 3-(1,1,1-trimethylhydrazin-1-ium-2-yl)propanoate 的两性离子通过 N-H⋯O 键稳定头尾二聚体；通过水分子的氢键形成无限链（一水合物，1）或 3D 网络（二水合物，2）。质子化形式的氢键（2-（2-羧乙基）-1,1,1-三甲基肼）产生无限链（氯化物，3）或二维网络（富马酸盐，4）。所有这些晶体都通过弱的 C–H⋯A 相互作用来稳定。− 100 °C 时的晶体学参数如下： 1 ：三斜晶系，空间群 P $$\stackrel{-}{1}$$ 1 - ；a、b、c (Å)：7.3360(5)、8.0667(5)、8.9416(6)；α = 99.752(4), β = 112.665(4), γ = 107.300(4)°,V = 441.32(5) Å 3 , Z = 2; 2 ：单斜晶系，空间群 P 2 1 / c；a, b, c (Å): 6.8854(4), 11.2483(7), 12.8254(8), β = 105.339(2) °, V = 957.93(10) Å 3, Z = 4; 3 : 单斜晶系, 空间群 P 2 1 / n；a, b, c (Å): 7.3625(4), 12.6486(7), 10.5211(6), β = 103.583(2)°, V = 952.38(9) Å 3, Z = 4; 4：单斜晶系，空间群 P 2 1 / c；a, b, c (Å): 6.3669(6), 29.516(3), 6.8145(7), β = 91.009(5) °, V = 1280.4(2) Å 3 , Z = 4. 结构 2 几乎相同到已经在室温下测量的那个。图形摘要 在晶体状态下，米屈肼的两性离子和质子化阳离子通过氢键网络组装