Synthesis and electrochemical characterization of 1,12-diferrocenyldodecane-tagged self-assembled monolayers

Abstract

The synthesis of 1, 12-diferrocenyldodecane and subsequently 6-(diferrocenyldodecanylcarbonyl)pentanethiol was completed according to the protocal detailed here. The intermediate and final products were characterized by mass spectrometry, 1H and 13C NMR, as applicable. Two of the intermediate compounds; 1, 12-diferrocenyldodecane-1, 12-dione and 1, 12-diferrocenyldodecane were analyzed via solution cyclic voltammetry. The formal potentials, ΔEp values, chemical and electrochemical reversibility and diffusion control of the electron transfer process were determined and compared to established values. The electrochemical properties of 1, 12-diferrocenyldodecane-tagged self-assembled monolayers adsorbed on gold electrodes were evaluated and compared to data obtained for similar compounds. The full width at half-maximum (FWHM), ΔEp's, formal potentials, degree of chemical and electrochemical reversibility, heterogenous electron transfer rate constants, and surface coverages were determined for the inner and outer ferrocenes. A low ration (8%) of surface coverage for the outer compared to the inner ferrocene was observed. The possible factors that may have led to the electrochemical inaccessibility of the outer ferrocene are discussed.