Crescent Oligoamides: From Acyclic “Macrocycles” to Folding Nanotubes

Abstract

Oligoarylamides whose backbones are rigidified by intramolecular hydrogen bonds (H-bonds) are found to adopt well-defined conformations in both solution and solid state. Depending on the length of their backbones, these folding oligoamides are crescents, broken macrocycles, or helices. A large (approximately 10 A) interior cavity is associated with the "macrocycles" and helices. The folded conformations are independent of chain length and are found in both nonpolar and polar solvents. This strategy is being extended to the construction of folding acyclic "macrocycles" and nanotubes with larger tubular cavities.

Molecular Apple Peels

“…[14][15][16][17][18] Helices derived from aromatic oligoamides (AOAs) may prove particularly suitable for the purpose of molecular recognition because their diameter can be tuned at will according to the size of the monomers and the orientation of the amine and acid groups on each aromatic ring. [16][17][18][19][20][21] Thus, hollows as large as 3 nm [19] and as low as 0.5 nm [17,18] have been reported for AOAs. A refinement of this concept is the design of an oligomeric sequence comprising both monomers that code for helical segments with a hollow and monomers that code for no hollow at all.…”

Complexation of two non-fully hydrogen bonded aromatic hydrazide heptamers toward n-octyl-α-L-glucopyranoside in chloroform

“…The six-membered intramolecular three-centered hydrogen bonding pattern of 1 and 2 has been well estabScheme 1 lished [13,18,19] . The 1 H NMR spectra of 1 and 2 in chloroform-d are of high resolution.…”

Biological Applications of Foldamers

“…The interactions responsible for structural stabilization are almost exclusively non-cooperative, although cooperative interactions are possible between nonadjacent units (see Chapter 1). Linear [119][120][121], cyclic [122][123][124], crescent-shaped [125,126], and helical [125][126][127][128][129] aryl amides have all been reported. However, bioactivity has only been introduced into the linear extended aryl amides.…”