Synthesis and surface-confined electrochemistry of dimethoxynaphthalene fused through rigid norbornylogous spacers to thiolate, dithiolate, and disulfide groups

A series of compounds (1-8) has been prepared in which a 1,4-dimethoxynaphthalene (DMN) group and either two thiol groups or a disulfide moiety are attached to the respective termini of rigid ''norbornylogous'' hydrocarbon bridges. 3, 5, 7, 9, and 13 bonds in length. Each of the the molecules forms an adsorbate monolayer when its CH2Cl2 solutions are exposed to etched gold. Chemically reversible one-electron oxidation of the DMN group is observed in CH2Cl2 or CH3CN at potentials of 0.54-0.67 V vs ferrocene. Repeated potential cycling demonstates less monolayer degradation (a) in CH2Cl2 compared to CH3CN and (b) at subambient temperatures. Fast cyclic voltammetry experiments establish that the electron-transfer rates between the naphthalene group and the electrode surface are very fast (> 10(8) s(-1)).