title: Elucidating the backbone conformation of photoswitchable foldamers using vibrational circular dichroism.
abstract: The backbone conformation of amphiphilic oligo(azobenzene) foldamers is investigated using vibrational circular dichroism (VCD) spectroscopy on a mode involving the stretching of the N=N bonds in the backbone. From denaturation experiments, we find that the VCD response in the helical conformation arises mainly from through-space interaction between the N=N-stretch transition-dipole moments, so that the coupled-oscillator model can be used to predict the VCD spectrum associated with a particular conformation. Using this approach, we elucidate the origin of the VCD signals in the folded conformation, and can assign the observed partial loss of VCD signals upon photo-induced unfolding to specific conformational changes. Our results show that the N=N-stretch VCD response provides an excellent probe of the helical conformation of the N=N bonds in this type of switchable molecular system.
authors.affiliation: Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands. s.woutersen@uva.nl.
authors.forename: Sérgio R
authors.initials: SR
authors.lastname: Domingos
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Roeters
authors.forename: Saeed
authors.initials: S
authors.lastname: Amirjalayer
authors.forename: Zhilin
authors.initials: Z
authors.lastname: Yu
authors.forename: Stefan
authors.initials: S
authors.lastname: Hecht
authors.forename: Sander
authors.initials: S
authors.lastname: Woutersen