@article {28592,
	title = {Helical Folding Competing with Unfolded Aggregation in Phenylene Ethynylene Foldamers},
	journal = {Chem. Eur. J.},
	volume = {22},
	number = {31},
	year = {2016},
	month = {2016 JUL 25},
	pages = {11028-11034},
	type = {Article},
	abstract = {The folding and aggregation behavior of a pair of oligo(phenylene ethynylene) (OPE) foldamers are investigated by means of UV/Vis absorption and circular dichroism spectroscopy. With identical OPE backbones, two foldamers, 1 with alkyl side groups and 2 with triethylene glycol side chains, manifest similar helical conformations in solutions in n-hexane and methanol, respectively. However, disparate and competing folding and aggregation processes are observed in alternative solvents. In cyclohexane, oligomer 1 initially adopts the helical conformation, but the self-aggregation of unfolded chains, as a minor component, gradually drives the folding-unfolding transition eventually to the unfolded aggregate state completely. In contrast, in aqueous solution (CH3OH/H2O) both folded and unfolded oligomer 2 appear to undergo self-association; aggregates of the folded chains are thermodynamically more stable. In solutions with a high H2O content, self-aggregation among unfolded oligomers is kinetically favored; these oligomers very slowly transform into aggregates of helical structures with greater thermodynamic stability. The folded-unfolded conformational switch thus takes place with the free (nonaggregated) molecules, and the very slow folding transition is due to the low concentration of molecularly dispersed oligomers.},
	isbn = {0947-65391521-3765},
	url = {http://dx.doi.org/10.1002/chem.201601804},
	author = {Luo, Zhouyang and Zhu, Ningbo and <strong>Zhao, Dahui*</strong>}
}
