Ferroelectricity of a Tetraphenylporphyrin Derivative Bearing −CONHC14H29 Chains at 500 K

Abstract

Optical properties of porphyrin derivatives were used to fabricate an artificial light-harvesting system. The introduction of a N–H···O═ hydrogen-bonding alkylamide chain (−CONHCnH2n+1) into a functional π-system is among the useful approaches to design multifunctional supramolecular assemblies. The tetraphenylporphyrin derivative bearing four −CONHC14H29 chains (1) shows the successive and reversible phase transition behavior of S1–S2 at 338 K, S2–Colr at 444 K, and Colr–I (isotropic liquid) at 564 K, where a fluidic discotic rectangular columnar (Colr) liquid crystal phase was observed in a wide temperature range of 444–564 K before melting. The one-dimensional columnar molecular assembly of (1)∞ was constructed using a simultaneous operation of N–H···O═ hydrogen-bonding and π-stacking interactions. Temperature (T)- and frequency (f)-dependent dielectric constants of 1 indicated characteristic dielectric enhancement at higher-T and lower-f conditions above 500 K because of the thermally activated motion...