Tubular and lamellar hydrogen-bonding molecular assemblies of isophthalic acid derivatives bearing a -CONHC n H 2 n +1 chain.

Isophthalic acid derivatives (CnIP), bearing alkylamide chains (-CONHC n H 2 n +1 : n = 6, 10, 14, and 18) at the 5-position that can participate in hydrogen bonding, were prepared and evaluated for their hydrogen-bonding molecular assembly structures for organogelation and liquid crystal formation. The hydrogen-bonding carboxylic acid (-COOH) groups form a ring-shaped (CnIP) 6 hexamer or a one-dimensional (1D) zig-zag (CnIP) ∞ chain. Although neither organogelation nor liquid crystal formation was observed in the isophthalic acid derivative bearing an alkoxy (-OC 14 H 29 ) chain, C14IP and C18IP derivatives could form both organogel and liquid crystal states through intermolecular N-H⋯O = amide-type hydrogen-bonding interactions. A discotic hexagonal columnar liquid crystal (Col h ) phase was observed in hydrated (C14IP) 6 ·(H 2 O) n and (C18IP) 6 ·(H 2 O) n , whereas a lamella-type liquid crystal (L a ) phase was confirmed in the unhydrated C18IP. In the Col h phase, O-H⋯O hydrogen-bonding ring-shaped (C14IP) 6 and (C18IP) 6 hexamers assembled to form the tubular molecular assembly stabilized by intermolecular-N-H⋯O = hydrogen-bonding interactions along the tube growth direction, where H 2 O molecules were contained within the hydrophilic space. On the other hand, the N-H⋯O = hydrogen-bonding interactions between the 1D zig-zag (CnIP) ∞ chains formed a layer-type molecular assembly of the L a -phase in the absence of water molecules.