A spectrophotometric investigation of alcohol complexes of manganese(III) in aqueous perchlorate media

Abstract

Spectral changes observed on the addition of primary alcohols to aqueous solutions of aquomanganese(III) ions are interpreted by the formation of alcoholaquomanganese(III) complexes. With methanol, ethanol, and n-propanol under water-rich conditions, only monoalcoholaquomanganese(III) ions, Mn³⁺(ROH)_aq and Mn³⁺(RO^–)_aq[or Mn³⁺OH^–(ROH)_aq] are formed, and values for the product of the extinction coefficient ε₁ and the formation constant β₁ are derived. No complexes are found with alcohols and Mn(II). These results are compared with data available for alcohol complexes of other cations. β₁ for the methanolaquomanganese(III) ion has a maximum in its temperature variation; this is compared with a similar maximum for alcoholaquoproton complexes.