Crystal structure of bis(9H-6-aminopurin-1-ium) hexafluoridosilicate(IV) dihydrate

Abstract

The asymmetric unit of the title compound, 2C5H6N5+·SiF62−·2H2O, contains one adeninium cation, half of a hexafluoridosilicate anion located on an inversion centre and one lattice water molecule. The adeninium cations are connected through N—H...N hydrogen bonds involving one H atom of the –NH2group and the H atom of the protonated N atom of the adenine ring system, forming centrosymmetric ring motifs of the typeR22(10) andR22(8), respectively. The overall connection of the cation leads to the formation of planar ribbons parallel to (122). In the ribbons, slipped π–π stacking interactions, with a centroid-to-centroid distance of 3.6938 (9) Å, an interplanar distance of 3.455 Å and a slippage of 1.306 Å is observed. The hexafluoridosilicate anion and the water molecule are linked through O—H...F hydrogen bonds [ring motifR44(12)] into chains parallel to [100]. The cationic ribbons and anionic chains are finally connected through additional N—H...O, N—H...F and O—H...F hydrogen bonds into a three-dimensional network in which layers of adeninium cations and fluoridosilicate anions alternate parallel to (001).