Figure 10
Part of the crystal structure of (4), showing chains formed by the hard hydrogen bonds linked into sheets by the soft hydrogen bonds. For the sake of clarity, H atoms not involved in the hydrogen bonding are omitted. The atoms marked with a star (*), hash (#), dollar sign ($) or ampersand (&) are at the symmetry positions (−2 + x, y, 1 + z), (2 + x, y, −1 + z), (1 − x, 1 − y, 1 − z) and (2 − x, −y, −z), respectively. |