IUCr journals
[Bonding structure]

2,4,6-Triamino-1,3,5-triazine-1H-isoindole-1,3(2H)-dione (1/3)

Acta Cryst. (2007). C63, o301–o302 [doi:10.1107/S0108270107015880]

This article describes the crystal structure of small organic molecules containing complementary arrays of hydrogen-bonding sites. The components of the crystal, i.e. melamine and phthalimide molecules, are interconnected via almost linear N–H⋅⋅⋅N and N–H⋅⋅⋅O hydrogen bonds into essentially planar C3H6N6 .3C8H5NO2 aggregates with pseudo-threefold symmetry. These aggregates, related by a twofold symmetry screw axis, interact via C–H⋅⋅⋅O contacts forming chains parallel to the b axis, whereas those related by a translation along the c axis interact via π–π interactions between the π clouds of aromatic rings forming a stacked structure. Both types of interactions, i.e. hydrogen bonding and π–π, stabilize the crystal structure. 

G.J. Perpétuo and J. Janczak