Tuning Helical Chirality in Polycyclic Ladder Systems

Rickhaus, Michel and Unke, Oliver T. and Mannancherry, Rajesh and Bannwart, Linda M. and Neuburger, Markus and Häussinger, Daniel and Mayor, Marcel. (2015) Tuning Helical Chirality in Polycyclic Ladder Systems. Chemistry - A European Journal, 21 (50). pp. 18156-18167.

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Official URL: http://edoc.unibas.ch/40741/

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Conceptually and experimentally, a new set of helical model compounds is presented herein that allow correlations between structural features and their expression in the secondary structure to be investigated. A cross-linked oligomer with two strands of mismatching lengths connected in a ladder-type fashion serves as a model system. Compensation for the dimensional mismatch leads to the adoption of a helical arrangement. A strategically placed relay ensures the continuity and uniformity of the helix. Upon exchanging the heteroatomic linkage, the helix responds by increasing or decreasing the torsion of the backbone. Inversion of the relay’s substitution pattern causes a distortion of the structure, while maintaining the directionality of the helix. Based on a short synthetic protocol with a modular precursor, four closely related “Geländer” oligomers (Geländer is the German word for bannister) were accessed and fully characterized. XRD analysis for one representative of each helical arrangement and complementary computational studies for the remaining derivatives allowed the impact of the alterations on the secondary structures to be studied. Isolation of pure enantiomers of all new Geländer oligomers provided insight into the racemization kinetics and estimation of the racemization barrier. In silico simulation of the electronic circular dichroism spectra of the model compounds enabled the helicity of the isolated samples to be assigned.
Faculties and Departments:05 Faculty of Science > Departement Chemie > Chemie > Molecular Devices and Materials (Mayor)
UniBasel Contributors:Mayor, Marcel and Häussinger, Daniel
Item Type:Article, refereed
Article Subtype:Research Article
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:25 Feb 2020 09:20
Deposited On:11 May 2016 13:40

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