1,1'-trimethylenebisthymine as synthetic model of dinucleotide TpT Electrochemical reduction

Abstract

The electrochemical reduction of 1,1'-trimethylenebisthymine (Thy(C3)Thy) in dimethylsulfoxide was investigated using dc polarography, cyclic voltammetry, controlled potential electrolysis and spectroelectrochemistry. Thy(C3)Thy is reduced in a two-election step (E1/2 = -2.40 V) to a diradical dianion which abstracts protons from the parent Thy(C3)Thy to form a neutral free diradical and the Thy(C3)Thy dianion. The neutral free diradical is further reduced and protonated to form 1,1'-trimethylenebisdihydrothymine. The dianion forms insoluble mercury salts producing up to three oxidation peaks (Epa between -0.35 and -0.07V). The effect of added base on the electrochemical and spectroelectrochemical behavior is described. The number of layers of the mercury- Thy(C3)Thy salt adsorbed in the anodic and stripped in the cathodic processes was calculated. The mechanism of adsorption is discussed.