Dynamic Motion of Twisted π System-Induced Temperature-Dependent Dielectric Response in the Neat Liquid State

Molecular
assemblies of twisted π molecules of tetraphenylene
with long alkoxy chains (1) and tetra­[2,3]­thienylene
with long alkylamide chains (2) or long alkoxy chains
(3) and their dielectric properties were investigated.
Different degrees of intermolecular interaction of 1–3 afforded different molecular assemblies, including an ordered
columnar structure, disordered columnar, and lamellar structures.
The introduction of long alkyl chains enabled us to create thermally
stable liquid crystalline or liquid states. Temperature-dependent
dielectric measurement revealed that the dynamic flipping motion of
the tetra­[2,3]­thienylene core of 3 induced a temperature-
and frequency-dependent dielectric anomaly in the neat liquid phase.
This flipping motion of the central tetra­[2,3]­thienylene π core
occurred relatively easily in the liquid state with a high degree
of freedom of molecular motion.