Heterocyclic inhibitors of autoxidation of hydrocarbons and alcohols

The antioxidant properties of heterocyclic metal complexes based on the derivatives of benzothiazole, isoxazole, and antipyrine were examined in the article. The ability to inhibit the oxidation of a heterocycle containing a fragment of thiobarbituric acid and a 4-nuclear metal chelate was studied. The results of the analysis of the particle sizes of the complexes using atomic force microscopy are given here. The inhibitory properties were studied by autoxidation of hydrocarbons (n-decane, n-dodecane) and benzyl alcohol. Among the metal complexes based on isoxazole derivatives, the metal chelate based on La, which almost completely inhibits the oxidation of benzyl alcohol, was the most effective. The copper complex based on benzothiazole was shown to reduce the oxidation rate of n-dodecane, while the Co metal complex accelerates its oxidation. Cu and Ni metal chelates based on antipyrine, a copper complex based on a benzothiazole and isoxazole derivative, and a sulfur-containing heterocycle with a thiocarbonyl fragment were found to be effective inhibitors of benzyl alcohol autoxidation. Increasing the number of metal atoms, which are prone to one-electron transformations in the central core of the complex to 4 (in our case, by introducing the Mn2Ni2 group) also contributes to antioxidant activity during the autoxidation of benzyl alcohol and n-decane.