Oxidation of para‐ and meta‐ Cresols by C‐ Meso‐5,7,7,12,14,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane‐Nickel (III), to the Corresponding Aldehydes in Aqueous Media

The tervalent nickel complex with C‐meso‐ 5,7,7,12,14,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane, Ni‐(III)L, as its disulphate form, Ni(III)L(SO₄)₂, oxidizes cresols in aqueous solutions. The major products after two electron equivalents are consumed are the corresponding hydroxybenzyl alcohols. The products after four electron equivalents are consumed are the corresponding hydroxybenzaldehydes. Excess tervalent nickel does not lead to the formation of the corresponding hydroxybenzoic acids. The results indicate that the oxidation reactions observed occur via the outer sphere mechanism. The use of NiL²⁺ as a catalyst for the oxidation of cresols is discussed.