Water molecules in hydroxy/acid networks as a competition between dynamics and bonding. Synthesis of a wet hydrophobic pore Original Research Article

In a model formed by hydroxy acids with a general structure (±)-1, we found that solid-state structures depend on steric interactions. Thus, with the exception of molecules 1b and 1e, compounds (±)-1a-(±)-1m, which possess bulky and conformationally rigid substituents, aggregate by forming tapes and sheets by alternating (+) and (−) subunits held together via carboxylic acid to alcohol hydrogen bonds. Homologue (±)-1n with conformationally flexible substituents, which allow conformational deformation gives, by way of the incorporation of water molecules, an efficient hexagonal assembly, which extends to the third-dimension to form tubular H-bonding networks. Each puckered channel can be described as being interconnected by closely packed hexagons in chair-like conformations. The ethyl groups presented in (±)-1n provided the volume required to lock the inner hexagonal wall into a rigid structure.