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Inicio » Actividades I+D > Publicaciones 2010 > 2,6-Diamino-9H-purine monohydrate and bi...
artículo con referato
"2,6-Diamino-9H-purine monohydrate and bis(2,6-diamino-9H-purin-1-ium) 2-(2-carboxylatophenyl)acetate heptahydrate: two simple structures with very complex hydrogen-bonding schemes"
A.M. Atria, M.T. Garland and R. Baggio
Acta Cryst. C 66(11) (2010) o547-o552
Two structures presenting an uncomplexed 2,6-diaminopurine (dap) group are reported, namely 2,6-diamino-9H-purine monohydrate, C5H6N6·H2O, (I), and bis(2,6-diamino-9H-purin-1-ium) 2-(2-carboxylatophenyl)acetate heptahydrate, 2C5H7N6+·C9H6O42-·7H2O, (II). Both structures are rather featureless from a molecular point of view, but present instead an outstanding hydrogen-bonding scheme. In compound (I), this is achieved through a rather simple independent unit content (one neutral dap and one water molecule) and takes the form of two-dimensional layers tightly connected by strong hydrogen bonds, and interlinked by much weaker hydrogen bonds and ππ interactions. In compound (II), the fundamental building blocks are more complex, consisting of two independent 2,6-diamino-9H-purin-1-ium (Hdap+) cations, one homophthalate [2-(2-carboxylatophenyl)acetate] dianion and seven solvent water molecules. The large number of hydrogen-bond donors and acceptors produces 26 independent interactions, leading to an extended and complicated network of hydrogen bonds in a packing organization characterized by the stacking of interleaved anionic and cationic planar arrays. These structural characteristics are compared with those of similar compounds in the literature.
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