Granisetron, an antiemetic drug, and its cobalt complex

The crystal structures of granisetron [systematic name: 1-methyl-N-(9-methyl-9-azabicyclo[3.3.1]nonan-7-yl)indazole-3-carboxamide], C(18)H(24)N(4)O, (I), an antinauseant and antiemetic agent, and its Co(II) complex, diaqua[1-methyl-N-(9-methyl-9-azoniabicyclo[3.3.1]nonan-7-yl)indazole-3-carboxamide]cobalt(II) tetrachloride dodecahydrate, [Co(C(18)H(25)N(4)O)(2)(H(2)O)(2)]Cl(4).12H(2)O, (II), have been determined by X-ray diffraction. The granisetron molecule is in an extended conformation in both structures. Twisting of the central carboxamide group facilitates the Co(II) coordination in (II). The Co(II) atom is located on an inversion centre. The azabicyclononane ring adopts a chair-boat conformation in both structures. The molecules in (I) are linked into centrosymmetric dimers and form tetracyclic rings through C-H...O hydrogen-bonding interactions. The simultaneous presence of free chloride ions in conjunction with a number of hydration water molecules in (II) provides interesting hydrogen-bond patterns. This study can aid in the investigation of the properties of metal complexes with active pharmaceuticals in which the drug molecules play the role of a ligand.