Stimuli-controlled self-assembly of diverse tubular aggregates from one single small monomer.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28401927.
- Also identified by DOI 10.1038/ncomms14943 and PMC identifier 5394284.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The design and synthesis of new stimuli-responsive hydrogen-bonding monomers that display a diversity of self-assembly pathways is of central importance in supramolecular chemistry. Here we describe the aggregation properties of a simple, intrinsically C<sub>2</sub>-symmetric enantiopure bicyclic cavity compound bearing a terminally unsubstituted ureidopyrimidinone fragment fused with a pyrrole moiety in different solvents and in the absence and presence of C<sub>60</sub> and C<sub>70</sub> guests. The tetrameric cyclic aggregate is selectively obtained in chlorinated solvents, where only part of the available hydrogen bonding sites are utilized, whereas in toluene or upon addition of C<sub>70</sub> guests, further aggregation into tubular supramolecular polymers is achieved. The open-end cyclic assemblies rearrange into a closed-shell capsule upon introduction of C<sub>60</sub> with an accompanied symmetry breaking of the monomer. Our study demonstrates that a C<sub>60</sub> switch can be used to simultaneously control the topology and occupancy of tubular assemblies resulting from the aggregation of small monomers.