Synthesis and electrochemistry of self-assembled monolayers containing quinone derivatives with varying electronic conjugation

We describe a new strategy for the generation of self-assembled monolayers of three different quinones from derivatives each containing a short oligo(phenylene vinylene) (OPV) bridge with a methyl protected aryl thiol at the base and 2,5-dimethoxybenzene as the headgroup connected through either a single, double or triple bond. After partial deprotection of both −SCH3 and −OCH3 groups using t-BuSNa as a dealkylation agent, self-assembled monolayers (SAMs) of each compound were formed on gold. Complete deprotection of the headgroup to generate the hydroquinone/quinone redox couple was accomplished electrochemically in 0.1 M H2SO4 using cyclic voltammetry. Electrochemical characterization as a function of the different bridging groups for the generated hydroquinone/quinone redox couple revealed formal potentials and redox reaction rates dramatically affected by small structural changes near the headgroup.