Chlorophyll a π-Cation Radical as Redox Mediator in Superoxide Dismutase (SOD) Mimetics

The extensive speciation of copper(II) chloride in organic solvents varies with concentration, temperature, pressure and oxygen content, providing the ability to switch between different chlorophyll transmetalation pathways. We found that one of them is exceptionally suitable for the formation and stabilisation of the chlorophyll pi-cation radical. This is due to unique redox cycling, which is coupled to the generation and transformation of various reactive oxygen species. In the presence of a proton donor, our system shows behavior which resembles that of superoxide dismutase (SOD). Regardless of light, chlorophyll acts as an electron transfer mediator.

Automated summary

Copper(II) chloride in organic solvents exhibit extensive speciation that allows switching between different chlorophyll transmetalation pathways, with one pathway particularly suitable for forming and stabilizing chlorophyll pi-cation radicals due to its unique redox cycling. In the presence of a proton donor, the system shows behavior similar to superoxide dismutase (SOD), and chlorophyll acts as an electron transfer mediator regardless of light conditions.