Discrete stacking of aromatic oligoamide macrocycles

J Am Chem Soc. 2015 May 13;137(18):5879-82. doi: 10.1021/jacs.5b02552. Epub 2015 Apr 30.

Abstract

Unlike the precise structural control typical of closed assemblies, curbing the stacking of disc- and ring-shaped molecules is quite challenging. Here we report the discrete stacking of rigid aromatic oligoamide macrocycles 1. With increasing concentration, the aggregation of 1 quickly plateaus, forming a discrete oligomer, as suggested by 1D (1)H, 2D nuclear Overhauser effect, and diffusion-ordered NMR spectroscopy. Quantum-chemical calculations indicate that the tetramer of 1 is the most stable among oligomeric stacks. X-ray crystallography revealed a tetrameric stack containing identical molecules adopting two different conformations. With a defined length and an inner pore capable of accommodating distinctly different guests, the tetramers of 1 densely pack into 2D layers. Besides being a rare system of conformation-regulated supramolecular oligomerization, the discrete stacks of 1, along with their higher-order assemblies, may offer new nanotechnological applications.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amides / chemistry*
  • Crystallography, X-Ray
  • Macrocyclic Compounds / chemistry*
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Molecular Structure
  • Quantum Theory

Substances

  • Amides
  • Macrocyclic Compounds