Sterically hindered phenol–dextran conjugates: radical scavenging activity in water and water–organic media

The radical scavenging activity investigation of sterically hindered phenols–dextran conjugates was carried out in water and water–dioxane mixtures with use of sodium salt of 2,2-diphenyl-1-picryl-hydrazyl sulfonic acid (DPPH-SO3Na). The suggestion was made that the reaction mechanism includes the one-electron transition stage. It was found that the reaction rate constants of DPPH-SO3Na with the conjugates are higher than the ones with low-molecular weight model. One of possible reasons for obtained data could be the fact that dextran hydration shell stabilizes the cation-radical intermediate in case of conjugates better than bulk water.