Effects of Ring Substitution on the Binding and Oxidation of Cyanophenols on Au(111) Electrodes

Abstract

The behavior of 2-, 3-, and 4-cyanophenol adsorbed on Au(111) has been studied using electrochemistry, potential difference FTIR, and in situ scanning tunneling microscopy (STM). Cyclic voltammetry displays a decreased oxidation current for cyanophenols substituted at the 2 or 4 positions on the ring. Surface FTIR bands are observed for 4-cyanophenol, while the 2- and 3-substituted molecules display no bands in the ring-stretching region. STM shows that 4-cyanophenol forms an ordered structure similar to that seen for phenol, while 3-cyanophenol does not appear to adopt an ordered structure on the Au(111) surface. These different behaviors relate to the different packing abilities of the differently substituted cyanophenols.