title: A folded, secondary structure in step-growth oligomers from covalently linked, crowded aromatics.
abstract: This study delineates general methods to create a new class of folded oligomers by covalently attaching overcrowded aromatics to each other. Crucial to observing the secondary structure in these oligomers was the employment of C-shaped linkers. These linkers preorganize the strands to form intramolecular hydrogen bonds. In solution, one- and two-dimensional (1)H NMR data show well-defined columnar conformations. The side chains in these oligomers are critical for the secondary structure to emerge in solution. Using tris(dodecyloxy)phenethyl side chains in combination with tert-butyl side chains in the terminal subunit provides a soluble trimer and prevents intermolecular association above millimolar concentrations. This new folding motif, formed through a synergy between hydrogen bonds and pi-stacking, is so robust that even dimers have secondary structure in solution.
authors.affiliation: Department of Chemistry, Columbia University, New York, New York 10027, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Dana
authors.initials: D
authors.lastname: Horoszewski
authors.forename: John
authors.initials: J
authors.lastname: Decatur
authors.forename: Colin
authors.initials: C
authors.lastname: Nuckolls