The Synthesis of Curved and Linear Structures from a Minimal Set of Monomers

Spiro-ladder oligomers of designed shape were assembled from a set of two enantiomeric bis-amino acid monomers. Two tetramers of differing monomer sequence were synthesized to study the effect of monomer stereochemistry upon macromolecular shape. Two-dimensional NMR experiments were used to determine the conformational preference of the monomers within the context of the oligomers. The results of this structural study were used to design two pentamers:  one resembling a rod and another with a curved shape. The pentamers were end-labeled with naphthyl and dansyl groups. The design hypothesis was confirmed by measuring the efficiency of fluorescence resonance energy transfer between the naphthyl and dansyl fluorophore pair.