Mesophases induced by hydrogen bonds between non-mesogens A di-proton acceptor and proton donors

A non-mesogen, consisting of two stilbazole moieties as proton accepting end groups linked by a triethylene glycol unit, was synthesized. Monotropic smectic B phases were observed for mixtures with nonanoic acid up to tetradecanoic acid as proton donors. Enantiotropic nematic and, in some cases, monotropic smectic A phases were observed with 4-methyl-, 4-methoxy- and 4-halo-benzoic acids as proton donors. The stability of the induced mesophases decreased with 3- and 2-substituted benzoic acids. No mesophase was observed with aliphatic dicarboxylic acids as donors. The results are explained on the basis of the nature and molecular interactions involving the constituent molecules.