Gelation and Structural Transformation Study of Some 1,3,5-Benzenetricarboxamide Derivatives

Short-chain
analogues of N,N′,N″-tris-(4-alkyl­phenyl)-1,3,5-benzenetricarboxamide
derivatives (methyl to butyl) are prepared, and their gelation study
renders a positive result for all, except the butyl derivative, in
both DMSO and DMSO/H2O. The crystal structure analysis
of the parent compound (1a) and its methyl (1b) and butyl (1e) derivatives shows columnar structures.
However, a notable difference has been observed within the columnar
structures of 1a or 1b and 1e. Detailed structural analysis was carried out to reason such varied
molecular assemblies, based on the deviation angle of amide groups,
along with the aid of some reported examples that reveal the structural
transformation of 1,3,5-benzenetricarboxamide derivatives from sheets
to different columnar structures. In addition, similarity in the simulated
powder pattern of the DMSO adducts of 1a and 1b and the experimental powder pattern of the xerogels of 1a and 1b indicates the possibility of similar packing
in both crystals and the fibers of the gel.