Light-mediated CO_(2)-responsiveness of metallopolymer microgels

摘要

Here, we report a finding on light-mediated CO_(2)^(-)responsiveness. It is found on the microgels that are made of side-chain type metallopolymers containing metalla-aromatics. Turbidity and laser light scattering studies on dilute aqueous dispersion of these microgels in dark indicate high CO_(2)^(-)responsivity, but poor reversibility upon N2 purge, which can be improved by exposing to light. This light-mediated CO_(2)^(-)responsiveness can be elucidated by the loss of aromaticity from initial photoexcitation and concurrent formation of a less reactive, antiaromatic excited state of relatively low CO_(2) binding affinity, and by subsequent relief of antiaromaticity that can enhance the CO_(2) removal. The finding is also checked by CO_(2) uptake-release experiments on the microgels, which enables both CO_(2) capture of high capacity and CO_(2) removal of good reversibility under a mild condition, allowing effective and reversible response to dilute CO_(2).