Flexibility Coexists with Shape-Persistence in Cyanostar Macrocycles

Yun Liu, Abhishek Singharoy, Christopher G. Mayne, Arkajyoti Sengupta, Krishnan Raghavachari, Klaus Schulten, Amar H. Flood

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

Shape-persistent macrocycles are attractive functional targets for synthesis, molecular recognition, and hierarchical self-assembly. Such macrocycles are noncollapsible and geometrically well-defined, and they are traditionally characterized by having repeat units and low conformational flexibility. Here, we find it necessary to refine these ideas in the face of highly flexible yet shape-persistent macrocycles. A molecule is shape-persistent if it has a small change in shape when perturbed by external stimuli (e.g., heat, light, and redox chemistry). In support of this idea, we provide the first examination of the relationships between a macrocycle's shape persistence, its conformational space, and the resulting functions. We do this with a star-shaped macrocycle called cyanostar that is flexible as well as being shape-persistent. We employed molecular dynamics (MD), density functional theory (DFT), and NMR experiments. Considering a thermal bath as a stimulus, we found a single macrocycle has 332 accessible conformers with olefins undergoing rapid interconversion by up-down and in-out motions on short time scales (0.2 ns). These many interconverting conformations classify single cyanostars as flexible. To determine and confirm that cyanostars are shape-persistent, we show that they have a high 87% shape similarity across these conformations. To further test the idea, we use the binding of diglyme to the single macrocycle as guest-induced stimulation. This guest has almost no effect on the conformational space. However, formation of a 2:1 sandwich complex involving two macrocycles enhances rigidity and dramatically shifts the conformer distribution toward perfect bowls. Overall, the present study expands the scope of shape-persistent macrocycles to include flexible macrocycles if, and only if, their conformers have similar shapes.

Original languageEnglish (US)
Pages (from-to)4843-4851
Number of pages9
JournalJournal of the American Chemical Society
Volume138
Issue number14
DOIs
StatePublished - Apr 27 2016
Externally publishedYes

Fingerprint

Conformations
Hot Temperature
Molecular recognition
Alkenes
Molecular Dynamics Simulation
Baths
Rigidity
Self assembly
Olefins
Oxidation-Reduction
Stars
Density functional theory
Molecular dynamics
Nuclear magnetic resonance
Light
Molecules
Experiments
diglyme

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Liu, Y., Singharoy, A., Mayne, C. G., Sengupta, A., Raghavachari, K., Schulten, K., & Flood, A. H. (2016). Flexibility Coexists with Shape-Persistence in Cyanostar Macrocycles. Journal of the American Chemical Society, 138(14), 4843-4851. https://doi.org/10.1021/jacs.6b00712

Flexibility Coexists with Shape-Persistence in Cyanostar Macrocycles. / Liu, Yun; Singharoy, Abhishek; Mayne, Christopher G.; Sengupta, Arkajyoti; Raghavachari, Krishnan; Schulten, Klaus; Flood, Amar H.

In: Journal of the American Chemical Society, Vol. 138, No. 14, 27.04.2016, p. 4843-4851.

Research output: Contribution to journalArticle

Liu, Y, Singharoy, A, Mayne, CG, Sengupta, A, Raghavachari, K, Schulten, K & Flood, AH 2016, 'Flexibility Coexists with Shape-Persistence in Cyanostar Macrocycles', Journal of the American Chemical Society, vol. 138, no. 14, pp. 4843-4851. https://doi.org/10.1021/jacs.6b00712
Liu, Yun ; Singharoy, Abhishek ; Mayne, Christopher G. ; Sengupta, Arkajyoti ; Raghavachari, Krishnan ; Schulten, Klaus ; Flood, Amar H. / Flexibility Coexists with Shape-Persistence in Cyanostar Macrocycles. In: Journal of the American Chemical Society. 2016 ; Vol. 138, No. 14. pp. 4843-4851.
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