Self-Assembled Multi-Component Catenanes: Structural Insights into an Adaptable Class of Molecular Receptors and [2]-Catenanes
Abstract
Under acidic conditions (50 equiv TFA), combinations of hydrazide A-B monomers self assemble into octameric [2] -catenanes with high selectivity for [1(sub3)2]sub2, where 1 is a D-Pro-X (X = Aib, Ac4c, Ac6c, L-4-Cl-PhGly) derived monomer and 2 is an L-Pro'-L-arylGly (Pro' = Pro, trans-F-Pro, trans-HO-Pro, aryl = naphthyl, phenyl) derived monomer. Five different combinations of monomers were studied by X-ray crystallography. In each case, the unique aryl glycine unit is located in the core of the structure where the aryl ring templates a CH-pi-CH sandwich. Analysis of metrical parameters indicate that this core region is highly conserved, while the more peripheral zones are flexible. 1H NMR spectroscopy indicate that the solid state structures are largely retained in solution, though several non-C2 symmetric compounds have a net C2-symmetry that indicate accessible dynamic processes. Catenane dynamic processes were additionally probed through H/D exchange, with the core being inflexible relative to the peripheral structure. Mass spectrometry was utilized to identify the constitutional isomerism in the minor asymmetric [1(sub5)2(sub3)] catenanes.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 11, 2012
- Accession Number
- ADA595300
Entities
People
- Marcey L. Waters
- Mee-kyung Chung
- Michel R Gagné
- Peter S. White
- Stephen J. Lee
Organizations
- University of North Carolina at Chapel Hill