Crystal Structure of Dacarbazine, Metoclopramide, and Acetylcholine Pentacyanopropenides

The crystal structures of new salt forms of the known nitrogen-containing pharmaceuticals (dacarbazine, metoclopramide, and acetylcholine) in which 1,1,2,3,3-pentacyanopropenide anion acts as a counterion are analyzed by X-ray diffraction. It is found that in the crystals of studied salts with dacarbazine (in the form of a monohydrate) and metoclopramide, the mentioned anion plays the role of a structure-forming spacer, linking with more than one cation by classical hydrogen bonds. The types of cation and anion localization in the studied salts are revealed. They are: layered in the crystals with dacarbazine, stacked with the cation and anion alternation in the crystals with metoclopramide, and anion columns surrounded by cations in the crystals with acetylcholine. The tendency of the pentacyanopropenide anion to disordering in the crystals of metoclopramide and acetylcholine salts is detected.