Figure 1.

Schemes showing the unfavorable hydrogen bonding geometry between odd carboxamide units (e.g., pimelamide) having the all-trans conformation (a) and the favourable interaction established according to the proposed structure where hydrogen bonds are established along two directions. (b). Corner and central chains are indicated by stick, and ball and stick representations for the shake of clarity. In the same way, a shorter dicarboxylic unit (i.e., pimelate) has been considered. Arrows indicate the shift of corner chains with respect to the central one. Color code: nitrogen, blue; oxygen, red; carbon, gray; hydrogen, brown. Reproduced with permission from [17], copyright 2015.