Figure 5
Space-filling view (van der Waals radii) of the staircase-like π-stacking for three layers (A, B and A′) of molecules in the crystal lattice of (II). The two experimentally distinct interplanar separations are indicated, leading to the packing sequence ABA′B′AB…, etc. Each molecule constitutes a `step' and is hydrogen bonded to the preceding and next step in the `staircase' (as in Fig. 4). |