Mediated kinetic medium effect in the reaction of bis-3,5-di-iso-propylsalicylatozinc(II) with tert-butylperoxyl radicals

In the reaction of ZnII(3,5-DIPS)2 with tert-butylOO radical, a mediated kinetic medium (solvent) effect is observed. The essence is that electron pair donors such as DMSO at molar equivalent quantities do not directly impede the reaction center of radical scavenging, but act indirectly by bonding axially to the central metalloelement zinc, which changes the coordination geometry in such a way as to increase intramolecular hydrogen bonding within the coordinated ligand and thus considerably diminish the fraction of OH groups available to transfer a hydrogen atom.