X-Ray structural studies on free and co-ordinated 6-amino-8-mercaptopurinium cation in bismuth(III) complexes

Abstract

Reaction of BiCl₃ with 6-amino-8-mercaptopurine (amp) in HCl solution results in the formation of [Hamp]₂[BiCl₅(Hamp)]Cl·5H₂O (2) and [Hamp][BiCl₅(Hamp)]·2H₂O (3). These complexes, together with the free ligand as a chloride, (1), have been characterized structurally by single-crystal X-ray diffraction showing that both the structures of (2) and (3) consist of [BiCl₅(Hamp)]^– anions, protonated ligand, and water molecules in different ratios; in addition, in (2) a Cl^– is present. In the complex anions the bismuth atom is octahedrally surrounded by five chlorines and one ligand molecule co-ordinated via sulphur; in each of the three structures base stacking is present. All data were collected using Mo–K_α radiation. The space groups are C2/c for (1), P2₁ for (2), and P for (3). The final R indices were 0.031, 0.047, and 0.038 respectively.