Spectroscopic, electrochemical and photochemical properties of brown ring compounds

Abstract

Brown ring compounds have been produced by the reaction of ferrous ion with nitric oxide and with nitrous acid in aqueous solution. Spectroscopic results have showed that the brown color is due to charge-transfer bands associated with the FeNO bond. The cyclic voltammetric experiments indicated that the oxidation of this compound was completely irreversible. The influence of light was to stimulate the charge-transfer process in which the electrons were transferred from the donor orbital into the acceptor orbital, and finally led to the formation of the ion-pair Fe(I)NO⁺ which was assumed to be more electroactive.