Quinoline Photobasicity: Investigation within Water‐Soluble Light‐Responsive Copolymers

Quinoline photobases exhibit a distinctly higher pK a in their electronically excited state than in the ground state, thereby enabling light‐controlled proton transfer reactions, for example, in molecular catalysis. The absorption of UV light translates to a pK a jump of approximately 10 units, as established for small‐molecule photobases. This contribution presents the first synthesis of quinoline‐based polymeric photobases prepared by reversible addition‐fragmentation chain‐transfer (RAFT) polymerization. The integration of quinolines as photobase chromophores within copolymers offers new possibilities for light‐triggered proton transfer in nanostructured materials, that is, in nanoparticles, at surfaces, membranes and interfaces. To exploit the light‐triggered reactivity of photobases within such materials, we first investigated how the ground‐ and excited‐state properties of the quinoline unit changes upon polymer integration. To address this matter, we combined absorption and emission spectroscopy with time‐resolved transient‐absorption studies to reveal photoinduced proton‐transfer dynamics in various solvents. The results yield important insights into the thermodynamic and kinetic properties of these polymeric quinoline photobases.
Back to base: We present the synthesis of the first polymeric photobase prepared by RAFT polymerization carrying quinolines moieties pendant to the polymer backbone. UV‐light‐induced proton capture is investigated within a representative molecular and macromolecular quinoline photobase regarding the influence on ground and excited state and enables insights into thermodynamic and kinetic properties.