Figure 2 A portio nof the packing diagram for (I), showing the double helical arrangement of molecules along [001]. For the sake of clarity, H atoms not involved in the motif shown have been omitted. [Symmetry code: (i) [{2\over 3}] - y, -[{2\over 3}] + x-y, -[{2\over 3}] + z]  [article HTML]