Figure 9
Rare carboxyl–carboxyl dimers involving the lone pair of the hydroxyl group (`hydroxyl dimers'). The C and O atoms not belonging to the interacting carboxyl groups are shown in light blue, N atoms are shown in magenta. The light blue spheres indicate that the molecule has been truncated for visualization purposes. (a) Antiplanar SS-A dimer (CACTUW; R = 0.04). Due to the size of the system, only the interacting fragments are shown. The unusually short carboxyl–Ow distance is given. The red asterisks mark the carboxyl groups involved in the ss-a dimer. (b) Antiplanar sa-s dimer (CAYJAO; R = 0.06). (c) Synplanar sa-s dimer involving two fumaric acid molecules (EMONAW; R = 0.11). The N-containing interacting molecule has been truncated due to its size. |