Ultrafast photoactivation of C─H bonds inside water-soluble nanocages.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30801018.
- Also identified by DOI 10.1126/sciadv.aav4806 and PMC identifier 6386559.
- Licence recorded as CC BY-NC.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Light energy absorbed by molecules can be harnessed to activate chemical bonds with extraordinary speed. However, excitation energy redistribution within various molecular degrees of freedom prohibits bond-selective chemistry. Inspired by enzymes, we devised a new photocatalytic scheme that preorganizes and polarizes target chemical bonds inside water-soluble cationic nanocavities to engineer selective functionalization. Specifically, we present a route to photoactivate weakly polarized sp<sup>3</sup> C─H bonds in water via host-guest charge transfer and control its reactivity with aerial O<sub>2</sub>. Electron-rich aromatic hydrocarbons self-organize inside redox complementary supramolecular cavities to form photoactivatable host-guest charge transfer complexes in water. An ultrafast C─H bond cleavage within ~10 to 400 ps is triggered by visible-light excitation, through a cage-assisted and solvent water-assisted proton-coupled electron transfer reaction. The confinement prolongs the lifetime of the carbon-centered radical to enable a facile yet selective reaction with molecular O<sub>2</sub> leading to photocatalytic turnover of oxidized products in water.