Hydrazide-based organogels and liquid crystals with columnar order

Abstract

We report on the synthesis and self-assembly of a new series of compounds containing a hydrazide unit in the rigid core and three alkoxy chains with varying lengths. The compounds N-(3,4,5-cetyloxybenzoyl)-N′-(4′-nitrobenzoyl) hydrazine (C16) and N-(3,4,5-dodecyloxybenzoyl)-N′-(4′-nitrobenzoyl) hydrazine (C12) exhibited stable columnar phase and strong gelation ability in several apolar organic solvents. The columnar structure was found both in the liquid crystalline state and in the xerogels by wide-angle X-ray diffraction analysis. SEM and TEM images revealed that the molecules self-assembled into twist fibrous aggregates in the xerogels. FT-IR and ¹H NMR studies confirmed that the intermolecular hydrogen bonding and van der Waals interactions were the major driving force for the formation of self-assembling both the liquid crystals and gels processes. Further detailed analysis of their aggregation modes were conducted by FT-IR spectroscopy and X-ray diffraction measurement.