Electrochemical control of the second harmonic generation property of self-assembled monolayers containing a trans-ferrocenyl-nitrophenyl ethylene group on gold

Results of a study revealed that the second harmonic (SH) intensity at gold electrodes modified with self-assembled monolayers (SAMs) of two novel molecules, which have trans-ferrocenyl-nitrophenyl ethylene and thiol groups as the second harmonic generation and surface-attached groups, was dependent on the oxidation state of the ferrocene group. The SH intensity rose when the ferrocene moiety of the SAMs was oxidized to the ferricenium cation. The molecular orientation change in each SAM upon reduction/oxidation of the ferrocene moiety was also studied by Fourier transform infrared reflection.