Spectrophotometric determination of the formation constants of the cupric halogen complexes with 1,3-propanediamine and 1,4-butanediamine in methanol solution and their activity on the oxidative coupling of the 2,6-di-tert-butylphenol

► We determined the formation constants of several copper(II) complexes with diamines. ► The catalytic capacity of these complexes was studied and evaluated. ► We observe a correlation among the catalytic activity and the speciation behavior. ► The complexes studied here show the highest catalytic capacity than their congeners.