USE OF ELECTROACTIVE THIOLS TO STUDY THE FORMATION AND EXCHANGE OF ALKANETHIOL MONOLAYERS ON GOLD

Treatment of mixed monolayers of hexadecanethiol and 16-(ferrocenylcarbonyloxy)hexadecanethiol on gold with solutions of alkanethiols results in the replacement of approximately one-third of the electroactive thiol. This exchange can be monitored by integration of the cyclic voltammetric wave. If this exchange is carried out with a second electroactive thiol, the signal from this species indicates adsorption, and diminution of the original signal represents desorption during exchange. Subsequent treatment of the three-component monolayer with a nonelectroactive thiol results in loss of the signal from the second electroactive species without loss of the original species. These results are consistent with exchange of thiols from defect sites, which are immobile over extended periods.