Transforming a C₃‑Symmetrical Liquid Crystal to a π‑Gelator by Alkoxy Chain Variation

Rational understanding of the structural features involving different noncovalent interactions is necessary to design a liquid crystal (LC) or an organogelator. Herein, we report the effect of the number and positions of alkoxy chains on the self-assembly induced physical properties of a few π-conjugated molecules. For this purpose, we designed and synthesized three C₃-symmetrical molecules based on oligo­(p-phenylenevinylene), C₃OPV1–3. The self-assembly properties of these molecules are studied in the solid and solution states. All of the three molecules follow the isodesmic self-assembly pathway. Upon cooling from isotropic melt, C₃OPV1 having nine alkoxy chains (−OC₁₂H₂₅) formed a columnar phase with two-dimensional rectangular lattice and retained the LC phase even at room temperature. Interestingly, when one of the −OC₁₂H₂₅ groups from each of the end benzene rings is knocked out, the resultant molecule, C₃OPV2 lost the LC property, however, transformed as a gelator in toluene and n-decane. Surprisingly, when the −OC₁₂H₂₅ group from the middle position is removed, the resultant molecule C₃OPV3 failed to form either the LC or the gel phases.