Stereochemical plasticity modulates cooperative binding in a CoII12L6 cuboctahedron

Biomolecular receptors are able to process information by responding differentially to combinations of chemical signals. Synthetic receptors that are likewise capable of multi-stimuli response can form the basis of programmable molecular systems, wherein specific input sequences create distinct outp...

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Bibliographic Details
Published in:Nature chemistry 2017-09, Vol.9 (9), p.903-908
Main Authors: Rizzuto, Felix J., Nitschke, Jonathan R.
Format: Article
Language:English
Subjects:
639/638/541/965
639/638/541/966
Analytical Chemistry
Anions
Binding
Biochemistry
Chemistry
Chemistry/Food Science
Cooperativity
Fullerenes
Information processing
Inorganic Chemistry
Organic Chemistry
Physical Chemistry
Receptors
Stimuli
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Summary:Biomolecular receptors are able to process information by responding differentially to combinations of chemical signals. Synthetic receptors that are likewise capable of multi-stimuli response can form the basis of programmable molecular systems, wherein specific input sequences create distinct outputs. Here we report a pseudo-cuboctahedral assembly capable of cooperatively binding anionic and neutral guest species. The binding of pairs of fullerene guests was observed to effect the all-or-nothing cooperative templation of an S 6 -symmetric host stereoisomer. This bis-fullerene adduct exhibits different cooperativity in binding pairs of anions from the fullerene-free parent: in one case, positive cooperativity is observed, while in another all binding affinities are enhanced by an order of magnitude, and in a third the binding events are only minimally perturbed. This intricate modulation of binding affinity, and thus cooperativity, renders our new cuboctahedral receptor attractive for incorporation into systems with complex, programmable responses to different sets of stimuli. An interconverting system of three distinct stereoisomers of a cuboctahedral Co II -based cage is able to regulate the binding affinities of large anionic guests. Through cooperative templation with fullerene guests, the cage converts into a desymmetrized cage that in turn exhibits positive cooperativity in binding of an icosahedral anion; this interaction is anti-cooperative in the fullerene-free parent.
ISSN:1755-4330
1755-4349
DOI:10.1038/nchem.2758