SUPRAMOLECULAR ASSEMBLIES OF DIACETYLENIC ALDONAMIDES

The study of novel amphiphiles that form nonspheroidal assemblies upon hydration is fundamental to understanding the relationship between molecular structure and supramolecular morphology. Structural components of previously reported amphiphiles were used to design the single chain diacetylenic aldonamides reported here. Open chain sugar headgroups were linked via an amide bond to a hydrophobic tail. Diacetylenes were incorporated in the alkyl chain both as a structural component and as a reactive unit. Photopolymerization was used to test the molecular ordering of the hydrophobic region of the assemblies and to enhance their thermal and chemical stability. The electron density of the diacetylenes allowed direct imaging of the assemblies by TEM. The morphology and reactivity of a series of N-dodeca-5,7-diynylaldonamides were determined. The aldonamides were derived from two aldoheptoses, D-glycero-D-gluconamide and D-glycero-L-mannonamide; four aldohexoses, D-galactonamide, D-gluconamide, L-mannonamide, and D-gulonomide; two aldopentoses, L-arbanonamide and L-lyxonamide; and two aldotetroses, L-threonamide and D-erythronamide. N-Dodecylaldonamide analogues were prepared and examined to evaluate the importance of the diacetylene group on the morphology. The microscopy and molecular modeling data indicate that at least two packing arrangements for these assemblies are possible. One is the head-to-head bilayer packing typical of most amphiphilic molecules; the other is a head-to-tail arrangement. The head-to-head packing results in assemblies which are planar, helical, or tubular. The head-to-tail packing arrangement and ''dromic'' hydrogen-bonding patterns are associated with fiber-like supramolecular assemblies. Numerous potential applications of tubule microstructures have been proposed. The relative ease of preparation of many of these aldonamide molecules and their assemblies recommends them for many of these applications.